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SubjectRe: [PATCH v2 4/4] media: tc358746: add Toshiba TC358746 Parallel to CSI-2 bridge driver
Hi Marco,

Thank you for the patch.

On Fri, Sep 16, 2022 at 03:45:35PM +0200, Marco Felsch wrote:
> Adding support for the TC358746 parallel <-> MIPI CSI bridge. This chip
> supports two operating modes:
> 1st) parallel-in -> mipi-csi out
> 2nd) mipi-csi in -> parallel out
>
> This patch only adds the support for the 1st mode.
>
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
> Changelog:
>
> v2:
> - use the correct CID_LINK_FREQ control to query the sensor_pclk_rate
> - remove now not needed tc358746_link_setup() and
> struct v4l2_ctrl sensor_pclk_ctrl
> - call v4l2_subdev_link_validate_default() during link validation
> - remove MEDIA_BUS_FMT_GBR888_1X24/YUV444 format support
> - use subdev active_state API
> - replace own .get_fmt with v4l2_subdev_get_fmt
> - remove unnecessary pad checks
> - restructure tc358746_get_format_by_code() if-case
> - move apply_dphy_config|apply_misc_config from resume intos s_stream
> - use goto in s_stream enable case
> - fix error handling in suspend/resume
> - split probe() into more sub-functions
> - use dev_dbg() for printing successful probe
>
> drivers/media/i2c/Kconfig | 17 +
> drivers/media/i2c/Makefile | 1 +
> drivers/media/i2c/tc358746.c | 1682 ++++++++++++++++++++++++++++++++++
> 3 files changed, 1700 insertions(+)
> create mode 100644 drivers/media/i2c/tc358746.c
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 7806d4b81716..aefb9c9e0c08 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -1272,6 +1272,23 @@ config VIDEO_TC358743_CEC
> When selected the tc358743 will support the optional
> HDMI CEC feature.
>
> +config VIDEO_TC358746
> + tristate "Toshiba TC358746 parallel-CSI2 bridge"
> + depends on VIDEO_DEV && I2C
> + select VIDEO_V4L2_SUBDEV_API
> + select MEDIA_CONTROLLER
> + select V4L2_FWNODE
> + select GENERIC_PHY_MIPI_DPHY
> + select REGMAP_I2C
> + select COMMON_CLK
> + help
> + Support for the Toshiba TC358746 parallel to MIPI CSI-2 bridge.
> + The bridge can work in both directions but currently only the
> + parallel-in / csi-out path is supported.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called tc358746.
> +
> config VIDEO_TVP514X
> tristate "Texas Instruments TVP514x video decoder"
> depends on VIDEO_DEV && I2C
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index 0a2933103dd9..d1096c2ab480 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -118,6 +118,7 @@ obj-$(CONFIG_VIDEO_SONY_BTF_MPX) += sony-btf-mpx.o
> obj-$(CONFIG_VIDEO_SR030PC30) += sr030pc30.o
> obj-$(CONFIG_VIDEO_ST_MIPID02) += st-mipid02.o
> obj-$(CONFIG_VIDEO_TC358743) += tc358743.o
> +obj-$(CONFIG_VIDEO_TC358746) += tc358746.o
> obj-$(CONFIG_VIDEO_TDA1997X) += tda1997x.o
> obj-$(CONFIG_VIDEO_TDA7432) += tda7432.o
> obj-$(CONFIG_VIDEO_TDA9840) += tda9840.o
> diff --git a/drivers/media/i2c/tc358746.c b/drivers/media/i2c/tc358746.c
> new file mode 100644
> index 000000000000..4f1a809b9fc3
> --- /dev/null
> +++ b/drivers/media/i2c/tc358746.c
> @@ -0,0 +1,1682 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * TC358746 - Parallel <-> CSI-2 Bridge
> + *
> + * Copyright 2022 Marco Felsch <kernel@pengutronix.de>
> + *
> + * Notes:
> + * - Currently only 'Parallel-in -> CSI-out' mode is supported!
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/phy/phy-mipi-dphy.h>
> +#include <linux/property.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-mc.h>
> +
> +/* 16-bit registers */
> +#define CHIPID_REG 0x0000
> +#define CHIPID GENMASK(15, 8)
> +
> +#define SYSCTL_REG 0x0002
> +#define SRESET BIT(0)
> +
> +#define CONFCTL_REG 0x0004
> +#define PDATAF_MASK GENMASK(9, 8)
> +#define PDATAF_MODE0 0
> +#define PDATAF_MODE1 1
> +#define PDATAF_MODE2 2
> +#define PDATAF(val) FIELD_PREP(PDATAF_MASK, (val))
> +#define PPEN BIT(6)
> +#define DATALANE_MASK GENMASK(1, 0)
> +
> +#define FIFOCTL_REG 0x0006
> +#define DATAFMT_REG 0x0008
> +#define PDFMT(val) FIELD_PREP(GENMASK(7, 4), (val))
> +
> +#define MCLKCTL_REG 0x000c
> +#define MCLK_HIGH_MASK GENMASK(15, 8)
> +#define MCLK_LOW_MASK GENMASK(7, 0)
> +#define MCLK_HIGH(val) FIELD_PREP(MCLK_HIGH_MASK, (val))
> +#define MCLK_LOW(val) FIELD_PREP(MCLK_LOW_MASK, (val))
> +
> +#define PLLCTL0_REG 0x0016
> +#define PLL_PRD_MASK GENMASK(15, 12)
> +#define PLL_PRD(val) FIELD_PREP(PLL_PRD_MASK, (val))
> +#define PLL_FBD_MASK GENMASK(8, 0)
> +#define PLL_FBD(val) FIELD_PREP(PLL_FBD_MASK, (val))
> +
> +#define PLLCTL1_REG 0x0018
> +#define PLL_FRS_MASK GENMASK(11, 10)
> +#define PLL_FRS(val) FIELD_PREP(PLL_FRS_MASK, (val))
> +#define CKEN BIT(4)
> +#define RESETB BIT(1)
> +#define PLL_EN BIT(0)
> +
> +#define CLKCTL_REG 0x0020
> +#define MCLKDIV_MASK GENMASK(3, 2)
> +#define MCLKDIV(val) FIELD_PREP(MCLKDIV_MASK, (val))
> +#define MCLKDIV_8 0
> +#define MCLKDIV_4 1
> +#define MCLKDIV_2 2
> +
> +#define WORDCNT_REG 0x0022
> +#define PP_MISC_REG 0x0032
> +#define FRMSTOP BIT(15)
> +#define RSTPTR BIT(14)
> +
> +/* 32-bit registers */
> +#define CLW_DPHYCONTTX_REG 0x0100
> +#define CLW_CNTRL_REG 0x0140
> +#define D0W_CNTRL_REG 0x0144
> +#define LANEDISABLE BIT(0)
> +
> +#define STARTCNTRL_REG 0x0204
> +#define START BIT(0)
> +
> +#define LINEINITCNT_REG 0x0210
> +#define LPTXTIMECNT_REG 0x0214
> +#define TCLK_HEADERCNT_REG 0x0218
> +#define TCLK_ZEROCNT(val) FIELD_PREP(GENMASK(15, 8), (val))
> +#define TCLK_PREPARECNT(val) FIELD_PREP(GENMASK(6, 0), (val))
> +
> +#define TCLK_TRAILCNT_REG 0x021C
> +#define THS_HEADERCNT_REG 0x0220
> +#define THS_ZEROCNT(val) FIELD_PREP(GENMASK(14, 8), (val))
> +#define THS_PREPARECNT(val) FIELD_PREP(GENMASK(6, 0), (val))
> +
> +#define TWAKEUP_REG 0x0224
> +#define TCLK_POSTCNT_REG 0x0228
> +#define THS_TRAILCNT_REG 0x022C
> +#define HSTXVREGEN_REG 0x0234
> +#define TXOPTIONCNTRL_REG 0x0238
> +#define CSI_CONTROL_REG 0x040C
> +#define CSI_MODE BIT(15)
> +#define TXHSMD BIT(7)
> +#define NOL(val) FIELD_PREP(GENMASK(2, 1), (val))
> +
> +#define CSI_CONFW_REG 0x0500
> +#define MODE(val) FIELD_PREP(GENMASK(31, 29), (val))
> +#define MODE_SET 0x5
> +#define ADDRESS(val) FIELD_PREP(GENMASK(28, 24), (val))
> +#define CSI_CONTROL_ADDRESS 0x3
> +#define DATA(val) FIELD_PREP(GENMASK(15, 0), (val))
> +
> +#define CSI_START_REG 0x0518
> +#define STRT BIT(0)
> +
> +static const struct v4l2_mbus_framefmt tc358746_def_fmt = {
> + .width = 640,
> + .height = 480,
> + .code = MEDIA_BUS_FMT_UYVY8_2X8,
> + .field = V4L2_FIELD_NONE,
> + .colorspace = V4L2_COLORSPACE_DEFAULT,
> + .ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT,
> + .quantization = V4L2_QUANTIZATION_DEFAULT,
> + .xfer_func = V4L2_XFER_FUNC_DEFAULT,
> +};
> +
> +static const char * const tc358746_supplies[] = {
> + "vddc", "vddio", "vddmipi"
> +};
> +
> +enum {
> + TC358746_SINK,
> + TC358746_SOURCE,
> + TC358746_NR_PADS
> +};
> +
> +struct tc358746 {
> + struct v4l2_subdev sd;
> + struct media_pad pads[TC358746_NR_PADS];
> + struct v4l2_async_notifier notifier;
> + struct v4l2_fwnode_endpoint csi_vep;
> +
> + struct v4l2_ctrl_handler ctrl_hdl;
> +
> + struct regmap *regmap;
> + struct clk *refclk;
> + struct gpio_desc *reset_gpio;
> + struct regulator_bulk_data supplies[ARRAY_SIZE(tc358746_supplies)];
> +
> + struct clk_hw mclk_hw;
> + unsigned long mclk_rate;
> + u8 mclk_prediv;
> + u16 mclk_postdiv;
> +
> + unsigned long pll_rate;
> + u8 pll_post_div;
> + u16 pll_pre_div;
> + u16 pll_mul;
> +
> +#define TC358746_VB_MAX_SIZE (511 * 32)
> +#define TC358746_VB_DEFAULT_SIZE (1 * 32)
> + unsigned int vb_size; /* Video buffer size in bits */
> +
> + struct phy_configure_opts_mipi_dphy dphy_cfg;
> +};
> +
> +static inline struct tc358746 *to_tc358746(struct v4l2_subdev *sd)
> +{
> + return container_of(sd, struct tc358746, sd);
> +}
> +
> +static inline struct tc358746 *clk_hw_to_tc358746(struct clk_hw *hw)
> +{
> + return container_of(hw, struct tc358746, mclk_hw);
> +}
> +
> +struct tc358746_format {
> + u32 code;
> + bool csi_format;
> + unsigned char bus_width;
> + unsigned char bpp;
> + /* Register values */
> + u8 pdformat; /* Peripheral Data Format */
> + u8 pdataf; /* Parallel Data Format Option */
> +};
> +
> +enum {
> + PDFORMAT_RAW8 = 0,
> + PDFORMAT_RAW10,
> + PDFORMAT_RAW12,
> + PDFORMAT_RGB888,
> + PDFORMAT_RGB666,
> + PDFORMAT_RGB565,
> + PDFORMAT_YUV422_8BIT,
> + /* RESERVED = 7 */
> + PDFORMAT_RAW14 = 8,
> + PDFORMAT_YUV422_10BIT,
> + PDFORMAT_YUV444,
> +};
> +
> +/* Check tc358746_src_mbus_code() if you add new formats */
> +static const struct tc358746_format tc358746_formats[] = {
> + {
> + .code = MEDIA_BUS_FMT_UYVY8_2X8,
> + .bus_width = 8,
> + .bpp = 16,
> + .pdformat = PDFORMAT_YUV422_8BIT,
> + .pdataf = PDATAF_MODE0,
> + }, {
> + .code = MEDIA_BUS_FMT_UYVY8_1X16,
> + .csi_format = true,
> + .bus_width = 16,
> + .bpp = 16,
> + .pdformat = PDFORMAT_YUV422_8BIT,
> + .pdataf = PDATAF_MODE1,
> + }, {
> + .code = MEDIA_BUS_FMT_YUYV8_1X16,
> + .csi_format = true,
> + .bus_width = 16,
> + .bpp = 16,
> + .pdformat = PDFORMAT_YUV422_8BIT,
> + .pdataf = PDATAF_MODE2,
> + }, {
> + .code = MEDIA_BUS_FMT_UYVY10_2X10,
> + .bus_width = 10,
> + .bpp = 20,
> + .pdformat = PDFORMAT_YUV422_10BIT,
> + .pdataf = PDATAF_MODE0, /* don't care */
> + }
> +};
> +
> +/* Get n-th format for pad */
> +static const struct tc358746_format *
> +tc358746_get_format_by_idx(unsigned int pad, unsigned int index)
> +{
> + unsigned int idx = 0;
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(tc358746_formats); i++) {
> + const struct tc358746_format *fmt = &tc358746_formats[i];
> +
> + if ((pad == TC358746_SOURCE && fmt->csi_format) ||
> + (pad == TC358746_SINK)) {
> + if (idx == index)
> + return fmt;
> + idx++;
> + }
> + }
> +
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static const struct tc358746_format *
> +tc358746_get_format_by_code(unsigned int pad, u32 code)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < ARRAY_SIZE(tc358746_formats); i++) {
> + const struct tc358746_format *fmt = &tc358746_formats[i];
> +
> + if (pad == TC358746_SINK && fmt->code == code)
> + return fmt;
> +
> + if (pad == TC358746_SOURCE && !fmt->csi_format)
> + continue;
> +
> + if (fmt->code == code)
> + return fmt;
> + }
> +
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static u32 tc358746_src_mbus_code(u32 code)
> +{
> + switch (code) {
> + case MEDIA_BUS_FMT_UYVY8_2X8:
> + return MEDIA_BUS_FMT_UYVY8_1X16;
> + case MEDIA_BUS_FMT_UYVY10_2X10:
> + return MEDIA_BUS_FMT_UYVY10_1X20;
> + default:
> + return code;
> + }
> +}
> +
> +static bool tc358746_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case SYSCTL_REG ... CSI_START_REG:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static bool tc358746_readable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case CHIPID_REG ... CSI_START_REG:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static const struct regmap_config tc358746_regmap_config = {
> + .name = "tc358746",
> + .reg_bits = 16,
> + .val_bits = 16,
> + .max_register = CSI_START_REG,
> + .writeable_reg = tc358746_writeable_reg,
> + .readable_reg = tc358746_readable_reg,
> + .reg_format_endian = REGMAP_ENDIAN_BIG,
> + .val_format_endian = REGMAP_ENDIAN_BIG,
> +};
> +
> +static int tc358746_write(struct tc358746 *tc358746, u32 reg, u32 val)
> +{
> + size_t count;
> +
> + /* 32-bit registers starting from CLW_DPHYCONTTX */
> + count = reg < CLW_DPHYCONTTX_REG ? 1 : 2;
> +
> + return regmap_bulk_write(tc358746->regmap, reg, &val, count);
> +}
> +
> +static int tc358746_read(struct tc358746 *tc358746, u32 reg, u32 *val)
> +{
> + size_t count;
> +
> + /* 32-bit registers starting from CLW_DPHYCONTTX */
> + count = reg < CLW_DPHYCONTTX_REG ? 1 : 2;
> + *val = 0;
> +
> + return regmap_bulk_read(tc358746->regmap, reg, val, count);
> +}
> +
> +static int
> +tc358746_update_bits(struct tc358746 *tc358746, u32 reg, u32 mask, u32 val)
> +{
> + u32 tmp, orig;
> + int err;
> +
> + err = tc358746_read(tc358746, reg, &orig);
> + if (err)
> + return err;
> +
> + tmp = orig & ~mask;
> + tmp |= val & mask;
> +
> + return tc358746_write(tc358746, reg, tmp);
> +}
> +
> +static int tc358746_set_bits(struct tc358746 *tc358746, u32 reg, u32 bits)
> +{
> + return tc358746_update_bits(tc358746, reg, bits, bits);
> +}
> +
> +static int tc358746_clear_bits(struct tc358746 *tc358746, u32 reg, u32 bits)
> +{
> + return tc358746_update_bits(tc358746, reg, bits, 0);
> +}
> +
> +static int tc358746_sw_reset(struct tc358746 *tc358746)
> +{
> + int err;
> +
> + err = tc358746_set_bits(tc358746, SYSCTL_REG, SRESET);
> + if (err)
> + return err;
> +
> + udelay(10);
> +
> + return tc358746_clear_bits(tc358746, SYSCTL_REG, SRESET);
> +}
> +
> +static int
> +tc358746_apply_pll_config(struct tc358746 *tc358746)
> +{
> + u8 post = tc358746->pll_post_div;
> + u16 pre = tc358746->pll_pre_div;
> + u16 mul = tc358746->pll_mul;
> + u32 val, mask;
> + int err;
> +
> + err = tc358746_read(tc358746, PLLCTL1_REG, &val);
> + if (err)
> + return err;
> +
> + /* Don't touch the PLL if running */
> + if (FIELD_GET(PLL_EN, val) == 1)
> + return 0;
> +
> + /* Pre-div and Multiplicator have a internal +1 logic */
> + val = PLL_PRD(pre - 1) | PLL_FBD(mul - 1);
> + mask = PLL_PRD_MASK | PLL_FBD_MASK;
> + err = tc358746_update_bits(tc358746, PLLCTL0_REG, mask, val);
> + if (err)
> + return err;
> +
> + val = PLL_FRS(ilog2(post)) | RESETB | PLL_EN;
> + mask = PLL_FRS_MASK | RESETB | PLL_EN;
> + tc358746_update_bits(tc358746, PLLCTL1_REG, mask, val);
> + if (err)
> + return err;
> +
> + udelay(1000);
> +
> + return tc358746_set_bits(tc358746, PLLCTL1_REG, CKEN);
> +}
> +
> +static int tc358746_apply_misc_config(struct tc358746 *tc358746)
> +{
> + struct v4l2_subdev *sd = &tc358746->sd;
> + struct v4l2_subdev_state *sink_state;
> + struct v4l2_mbus_framefmt *mbusfmt;

This can be const.

> + const struct tc358746_format *fmt;
> + struct device *dev = sd->dev;
> + u32 val;
> + int err;
> +
> + sink_state = v4l2_subdev_lock_and_get_active_state(sd);
> + mbusfmt = v4l2_subdev_get_pad_format(sd, sink_state, TC358746_SINK);
> + v4l2_subdev_unlock_state(sink_state);

You should keep the state locked until the end of this function,
otherwise the format could change.

> +
> + fmt = tc358746_get_format_by_code(TC358746_SINK, mbusfmt->code);
> +
> + /* Self defined CSI user data type id's are not supported yet */
> + val = PDFMT(fmt->pdformat);
> + dev_dbg(dev, "DATAFMT: 0x%x\n", val);
> + err = tc358746_write(tc358746, DATAFMT_REG, val);
> + if (err)
> + return err;
> +
> + val = PDATAF(fmt->pdataf);
> + dev_dbg(dev, "CONFCTL[PDATAF]: 0x%x\n", fmt->pdataf);
> + err = tc358746_update_bits(tc358746, CONFCTL_REG, PDATAF_MASK, val);
> + if (err)
> + return err;
> +
> + val = tc358746->vb_size / 32;
> + dev_dbg(dev, "FIFOCTL: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, FIFOCTL_REG, val);
> + if (err)
> + return err;
> +
> + /* Total number of bytes for each line/width */
> + val = mbusfmt->width * fmt->bpp / 8;
> + dev_dbg(dev, "WORDCNT: %u (0x%x)\n", val, val);
> + return tc358746_write(tc358746, WORDCNT_REG, val);
> +}
> +
> +#ifndef MHZ
> +#define MHZ (1000 * 1000)
> +#endif
> +
> +/* Use MHz as base so the div needs no u64 */
> +static u32 tc358746_cfg_to_cnt(unsigned int cfg_val,
> + unsigned int clk_mhz,
> + unsigned int time_base)
> +{
> + return DIV_ROUND_UP(cfg_val * clk_mhz, time_base);
> +}
> +
> +static u32 tc358746_ps_to_cnt(unsigned int cfg_val,
> + unsigned int clk_mhz)
> +{
> + return tc358746_cfg_to_cnt(cfg_val, clk_mhz, USEC_PER_SEC);
> +}
> +
> +static u32 tc358746_us_to_cnt(unsigned int cfg_val,
> + unsigned int clk_mhz)
> +{
> + return tc358746_cfg_to_cnt(cfg_val, clk_mhz, 1);
> +}
> +
> +static int tc358746_apply_dphy_config(struct tc358746 *tc358746)
> +{
> + struct phy_configure_opts_mipi_dphy *cfg = &tc358746->dphy_cfg;
> + bool non_cont_clk = !!(tc358746->csi_vep.bus.mipi_csi2.flags &
> + V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK);
> + struct device *dev = tc358746->sd.dev;
> + unsigned long hs_byte_clk, hf_clk;
> + u32 val, val2, lptxcnt;
> + int err;
> +
> + /* The hs_byte_clk is also called SYSCLK in the excel sheet */
> + hs_byte_clk = cfg->hs_clk_rate / 8;
> + hs_byte_clk /= MHZ;
> + hf_clk = hs_byte_clk / 2;
> +
> + val = tc358746_us_to_cnt(cfg->init, hf_clk) - 1;
> + dev_dbg(dev, "LINEINITCNT: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, LINEINITCNT_REG, val);
> + if (err)
> + return err;
> +
> + val = tc358746_ps_to_cnt(cfg->lpx, hs_byte_clk) - 1;
> + lptxcnt = val;
> + dev_dbg(dev, "LPTXTIMECNT: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, LPTXTIMECNT_REG, val);
> + if (err)
> + return err;
> +
> + val = tc358746_ps_to_cnt(cfg->clk_prepare, hs_byte_clk) - 1;
> + val2 = tc358746_ps_to_cnt(cfg->clk_zero, hs_byte_clk) - 1;
> + dev_dbg(dev, "TCLK_PREPARECNT: %u (0x%x)\n", val, val);
> + dev_dbg(dev, "TCLK_ZEROCNT: %u (0x%x)\n", val2, val2);
> + dev_dbg(dev, "TCLK_HEADERCNT: 0x%x\n",
> + (u32)(TCLK_PREPARECNT(val) | TCLK_ZEROCNT(val2)));
> + err = tc358746_write(tc358746, TCLK_HEADERCNT_REG,
> + TCLK_PREPARECNT(val) | TCLK_ZEROCNT(val2));
> + if (err)
> + return err;
> +
> + val = tc358746_ps_to_cnt(cfg->clk_trail, hs_byte_clk);
> + dev_dbg(dev, "TCLK_TRAILCNT: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, TCLK_TRAILCNT_REG, val);
> + if (err)
> + return err;
> +
> + val = tc358746_ps_to_cnt(cfg->hs_prepare, hs_byte_clk) - 1;
> + val2 = tc358746_ps_to_cnt(cfg->hs_zero, hs_byte_clk) - 1;
> + dev_dbg(dev, "THS_PREPARECNT: %u (0x%x)\n", val, val);
> + dev_dbg(dev, "THS_ZEROCNT: %u (0x%x)\n", val2, val2);
> + dev_dbg(dev, "THS_HEADERCNT: 0x%x\n",
> + (u32)(THS_PREPARECNT(val) | THS_ZEROCNT(val2)));
> + err = tc358746_write(tc358746, THS_HEADERCNT_REG,
> + THS_PREPARECNT(val) | THS_ZEROCNT(val2));
> + if (err)
> + return err;
> +
> + /* TWAKEUP > 1ms in lptxcnt steps */
> + val = tc358746_us_to_cnt(cfg->wakeup, hs_byte_clk);
> + val = val / (lptxcnt + 1) - 1;
> + dev_dbg(dev, "TWAKEUP: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, TWAKEUP_REG, val);
> + if (err)
> + return err;
> +
> + val = tc358746_ps_to_cnt(cfg->clk_post, hs_byte_clk);
> + dev_dbg(dev, "TCLK_POSTCNT: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, TCLK_POSTCNT_REG, val);
> + if (err)
> + return err;
> +
> + val = tc358746_ps_to_cnt(cfg->hs_trail, hs_byte_clk);
> + dev_dbg(dev, "THS_TRAILCNT: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, THS_TRAILCNT_REG, val);
> + if (err)
> + return err;
> +
> + dev_dbg(dev, "CONTCLKMODE: %u", non_cont_clk ? 0 : 1);
> + return tc358746_write(tc358746, TXOPTIONCNTRL_REG, non_cont_clk ? 0 : 1);
> +}
> +
> +#define MAX_DATA_LANES 4
> +
> +static int tc358746_enable_csi_lanes(struct tc358746 *tc358746, int enable)
> +{
> + unsigned int lanes = tc358746->dphy_cfg.lanes;
> + unsigned int lane;
> + u32 reg, val;
> + int err;
> +
> + err = tc358746_update_bits(tc358746, CONFCTL_REG, DATALANE_MASK,
> + lanes - 1);
> + if (err)
> + return err;
> +
> + /* Clock lane */
> + val = enable ? 0 : LANEDISABLE;
> + dev_dbg(tc358746->sd.dev, "CLW_CNTRL: 0x%x\n", val);
> + err = tc358746_write(tc358746, CLW_CNTRL_REG, val);
> + if (err)
> + return err;
> +
> + for (lane = 0; lane < MAX_DATA_LANES; lane++) {
> + /* Data lanes */
> + reg = D0W_CNTRL_REG + lane * 0x4;
> + val = (enable && lane < lanes) ? 0 : LANEDISABLE;
> +
> + dev_dbg(tc358746->sd.dev, "D%uW_CNTRL: 0x%x\n", lane, val);
> + err = tc358746_write(tc358746, reg, val);
> + if (err)
> + return err;
> + }
> +
> + val = 0;
> + if (enable) {
> + /* Clock lane */
> + val |= BIT(0);
> +
> + /* Data lanes */
> + for (lane = 1; lane <= lanes; lane++)
> + val |= BIT(lane);
> + }
> +
> + dev_dbg(tc358746->sd.dev, "HSTXVREGEN: 0x%x\n", val);
> + return tc358746_write(tc358746, HSTXVREGEN_REG, val);
> +}
> +
> +static int tc358746_enable_csi_module(struct tc358746 *tc358746, int enable)
> +{
> + unsigned int lanes = tc358746->dphy_cfg.lanes;
> + int err;
> +
> + /*
> + * START and STRT are only reseted/disabled by sw reset. This is
> + * required to put the lane state back into LP-11 state. The sw reset
> + * don't reset register values.
> + */
> + if (!enable)
> + return tc358746_sw_reset(tc358746);
> +
> + err = tc358746_write(tc358746, STARTCNTRL_REG, START);
> + if (err)
> + return err;
> +
> + err = tc358746_write(tc358746, CSI_START_REG, STRT);
> + if (err)
> + return err;
> +
> + /* CSI_CONTROL_REG is only indirect accessible */
> + return tc358746_write(tc358746, CSI_CONFW_REG,
> + MODE(MODE_SET) |
> + ADDRESS(CSI_CONTROL_ADDRESS) |
> + DATA(CSI_MODE | TXHSMD | NOL(lanes - 1)));
> +}
> +
> +static int tc358746_enable_parallel_port(struct tc358746 *tc358746, int enable)
> +{
> + int err;
> +
> + if (enable) {
> + err = tc358746_write(tc358746, PP_MISC_REG, 0);
> + if (err)
> + return err;
> +
> + return tc358746_set_bits(tc358746, CONFCTL_REG, PPEN);
> + }
> +
> + err = tc358746_set_bits(tc358746, PP_MISC_REG, FRMSTOP);
> + if (err)
> + return err;
> +
> + err = tc358746_clear_bits(tc358746, CONFCTL_REG, PPEN);
> + if (err)
> + return err;
> +
> + return tc358746_set_bits(tc358746, PP_MISC_REG, RSTPTR);
> +}
> +
> +static inline struct v4l2_subdev *tc358746_get_remote_sd(struct media_pad *pad)
> +{
> + pad = media_pad_remote_pad_first(pad);
> + if (!pad)
> + return NULL;
> +
> + return media_entity_to_v4l2_subdev(pad->entity);
> +}
> +
> +static int tc358746_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> + struct tc358746 *tc358746 = to_tc358746(sd);
> + struct v4l2_subdev *src;
> + int err;
> +
> + dev_dbg(sd->dev, "%sable\n", enable ? "en" : "dis");
> +
> + src = tc358746_get_remote_sd(&tc358746->pads[TC358746_SINK]);
> + if (!src)
> + return -EPIPE;
> +
> + if (enable) {
> + err = pm_runtime_resume_and_get(sd->dev);
> + if (err)
> + return err;
> +
> + err = tc358746_apply_dphy_config(tc358746);
> + if (err)
> + goto err_out;
> +
> + err = tc358746_apply_misc_config(tc358746);
> + if (err)
> + goto err_out;
> +
> + err = tc358746_enable_csi_lanes(tc358746, 1);
> + if (err)
> + goto err_out;
> +
> + err = tc358746_enable_csi_module(tc358746, 1);
> + if (err)
> + goto err_out;
> +
> + err = tc358746_enable_parallel_port(tc358746, 1);
> + if (err)
> + goto err_out;
> +
> + err = v4l2_subdev_call(src, video, s_stream, 1);
> + if (err)
> + goto err_out;
> +
> + return err;
> +
> +err_out:
> + pm_runtime_mark_last_busy(sd->dev);
> + pm_runtime_put_sync_autosuspend(sd->dev);
> +
> + return err;
> + }
> +
> + /*
> + * Lane disable trigger state change from LP-11 to LP-00
> + * therefore it must happen before the CSI modile is disabled.
> + */
> + err = tc358746_enable_csi_lanes(tc358746, 0);
> + if (err)
> + return err;
> +
> + err = tc358746_enable_csi_module(tc358746, 0);
> + if (err)
> + return err;
> +
> + err = tc358746_enable_parallel_port(tc358746, 0);
> + if (err)
> + return err;
> +
> + pm_runtime_mark_last_busy(sd->dev);
> + pm_runtime_put_sync_autosuspend(sd->dev);
> +
> + return v4l2_subdev_call(src, video, s_stream, 0);
> +}
> +
> +static int tc358746_init_cfg(struct v4l2_subdev *sd,
> + struct v4l2_subdev_state *state)
> +{
> + struct v4l2_mbus_framefmt *fmt;
> +
> + fmt = v4l2_subdev_get_pad_format(sd, state, TC358746_SINK);
> + *fmt = tc358746_def_fmt;
> +
> + fmt = v4l2_subdev_get_pad_format(sd, state, TC358746_SOURCE);
> + *fmt = tc358746_def_fmt;
> + fmt->code = tc358746_src_mbus_code(tc358746_def_fmt.code);
> +
> + return 0;
> +}
> +
> +static int tc358746_enum_mbus_code(struct v4l2_subdev *sd,
> + struct v4l2_subdev_state *sd_state,
> + struct v4l2_subdev_mbus_code_enum *code)
> +{
> + const struct tc358746_format *fmt;
> +
> + fmt = tc358746_get_format_by_idx(code->pad, code->index);
> + if (IS_ERR(fmt))
> + return PTR_ERR(fmt);
> +
> + code->code = fmt->code;
> +
> + return 0;
> +}
> +
> +static int tc358746_set_fmt(struct v4l2_subdev *sd,
> + struct v4l2_subdev_state *sd_state,
> + struct v4l2_subdev_format *format)
> +{
> + struct v4l2_mbus_framefmt *src_fmt, *sink_fmt;
> + const struct tc358746_format *fmt;
> +
> + /* Source follows the sink */
> + if (format->pad == TC358746_SOURCE)
> + return 0;

You need to get the source pad format here and copy it to format,
otherwise userspace will think whatever format it has passed has been
accepted.

> +
> + sink_fmt = v4l2_subdev_get_pad_format(sd, sd_state, TC358746_SINK);
> +
> + fmt = tc358746_get_format_by_code(format->pad, format->format.code);
> + if (IS_ERR(fmt))
> + fmt = tc358746_get_format_by_code(format->pad, tc358746_def_fmt.code);
> +
> + format->format.code = fmt->code;
> + format->format.field = V4L2_FIELD_NONE;
> +

Is there no constraint at all on the width and height ? I would expect
zero width or height to be invalid for instance, and the width to be
required to be a multiple of 2 for YUV 4:2:2 formats.

> + dev_dbg(sd->dev, "Update format: %ux%u code:0x%x -> %ux%u code:0x%x",
> + sink_fmt->width, sink_fmt->height, sink_fmt->code,
> + format->format.width, format->format.height, format->format.code);
> +
> + *sink_fmt = format->format;
> +
> + src_fmt = v4l2_subdev_get_pad_format(sd, sd_state, TC358746_SOURCE);
> + *src_fmt = *sink_fmt;
> + src_fmt->code = tc358746_src_mbus_code(sink_fmt->code);
> +
> + return 0;
> +}
> +
> +static unsigned long tc358746_find_pll_settings(struct tc358746 *tc358746,
> + unsigned long refclk,
> + unsigned long fout)
> +
> +{
> + struct device *dev = tc358746->sd.dev;
> + unsigned long best_freq = 0;
> + u32 min_delta = 0xffffffff;
> + u16 prediv_max = 17;
> + u16 prediv_min = 1;
> + u16 m_best, mul;
> + u16 p_best, p;
> + u8 postdiv;
> +
> + if (fout > 1000 * MHZ) {
> + dev_err(dev, "HS-Clock above 1 Ghz are not supported\n");
> + return 0;
> + } else if (fout >= 500 * MHZ)

If one branch of an if uses curly braces, all should. You can work
around this by turning this else if into an if.

> + postdiv = 1;
> + else if (fout >= 250 * MHZ)
> + postdiv = 2;
> + else if (fout >= 125 * MHZ)
> + postdiv = 4;
> + else
> + postdiv = 8;
> +
> + for (p = prediv_min; p <= prediv_max; p++) {
> + unsigned long delta, fin;
> + u64 tmp;
> +
> + fin = DIV_ROUND_CLOSEST(refclk, p);
> + if (fin < 4 * MHZ || fin > 40 * MHZ)
> + continue;
> +
> + tmp = fout * p * postdiv;
> + do_div(tmp, fin);
> + mul = tmp;
> + if (mul > 511)
> + continue;
> +
> + tmp = mul * fin;
> + do_div(tmp, p * postdiv);
> +
> + delta = abs(fout - tmp);
> + if (delta < min_delta) {
> + p_best = p;
> + m_best = mul;
> + min_delta = delta;
> + best_freq = tmp;
> + };
> +
> + if (delta == 0)
> + break;
> + };
> +
> + if (!best_freq) {
> + dev_err(dev, "Failed find PLL frequency\n");
> + return 0;
> + }
> +
> + tc358746->pll_post_div = postdiv;
> + tc358746->pll_pre_div = p_best;
> + tc358746->pll_mul = m_best;
> +
> + if (best_freq != fout)
> + dev_warn(dev, "Request PLL freq:%lu, found PLL freq:%lu\n",
> + fout, best_freq);
> +
> + dev_dbg(dev, "Found PLL settings: freq:%lu prediv:%u multi:%u postdiv:%u\n",
> + best_freq, p_best, m_best, postdiv);
> +
> + return best_freq;
> +}
> +
> +#define TC358746_PRECISION 10
> +
> +static int
> +tc358746_link_validate(struct v4l2_subdev *sd, struct media_link *link,
> + struct v4l2_subdev_format *source_fmt,
> + struct v4l2_subdev_format *sink_fmt)
> +{
> + struct tc358746 *tc358746 = to_tc358746(sd);
> + unsigned long csi_bitrate, sensor_bitrate;
> + struct v4l2_subdev_state *sink_state;
> + struct v4l2_mbus_framefmt *mbusfmt;
> + const struct tc358746_format *fmt;
> + unsigned int fifo_sz, tmp, n;
> + struct v4l2_subdev *sensor;
> + s64 sensor_pclk_rate;
> + int err;
> +
> + err = v4l2_subdev_link_validate_default(sd, link, source_fmt, sink_fmt);
> + if (err)
> + return err;
> +
> + sink_state = v4l2_subdev_lock_and_get_active_state(sd);

This makes me thinkg we should pass the state to this function. Not
something that needs to be addressed in this patch of course.

> + mbusfmt = v4l2_subdev_get_pad_format(sd, sink_state, TC358746_SINK);
> + v4l2_subdev_unlock_state(sink_state);

I'd release the lock at the end of the function, to make sure the format
won't change during validation. This is also a race condition in the
subdev core and should be fixed there, I'd be fine if you ignored it
here for now.

> +
> + /* Check the FIFO settings */
> + fmt = tc358746_get_format_by_code(TC358746_SINK, mbusfmt->code);
> + if (IS_ERR(fmt))
> + return PTR_ERR(fmt);

Can this happen if the format has been validate at set_fmt time ?

> +
> + sensor = media_entity_to_v4l2_subdev(link->source->entity);
> + sensor_pclk_rate = v4l2_get_link_freq(sensor->ctrl_handler, 0, 0);

Shouldn't you set the last two arguments to non-zero values, to support
sources that only implement the V4L2_CID_PIXEL_RATE control ?

I'd also name the variable source_link_freq, as it may not be a sensor,
and it's a link frequency, not a pixel clock rate.

> + if (sensor_pclk_rate <= 0) {
> + dev_err(tc358746->sd.dev,
> + "Failed to query or invalid sensor link frequency\n");
> + /* Return -EINVAL in case of sensor_pclk_rate is 0 */
> + return sensor_pclk_rate ? : -EINVAL;
> + }
> + sensor_bitrate = sensor_pclk_rate * fmt->bus_width;
> +
> + csi_bitrate = tc358746->dphy_cfg.lanes * tc358746->pll_rate;
> +
> + dev_dbg(tc358746->sd.dev,
> + "Fifo settings params: sensor-bitrate:%lu csi-bitrate:%lu",
> + sensor_bitrate, csi_bitrate);
> +
> + /* Avoid possible FIFO overflows */
> + if (csi_bitrate < sensor_bitrate) {
> + dev_err(sd->dev,
> + "Link validation failed csi-bitrate:%lu < sensor-bitrate:%lu\n",
> + csi_bitrate, sensor_bitrate);

As this can be triggered by userspace, I'd make it a dev_dbg().

> + return -EINVAL;
> + }
> +
> + /* Best case */
> + if (csi_bitrate == sensor_bitrate) {
> + tc358746->vb_size = TC358746_VB_DEFAULT_SIZE;
> + goto out;
> + }
> +
> + /*
> + * Avoid possible FIFO underflow in case of
> + * csi_bitrate > sensor_bitrate. For such case the chip has a internal
> + * fifo which can be used to delay the line output.
> + *
> + * Fifo size calculation:
> + *
> + * fifo-sz, image-width - in bits
> + * sbr - sensor_bitrate in bits/s
> + * csir - csi_bitrate in bits/s
> + *
> + * 1 1 1
> + * image-width * --- + fifo-sz --- >= ---- * image-width
> + * sbr sbr csir

Given that csir > sbr, 1/csir < 1 sbr, so this will always be true,
even with fifo-sz set to 0. Am I missing something ?

> + *
> + * fifo-sz >= abs(sbr/csir * image-width - image-width)
> + * `-----´
> + * n

The n variable doesn't store sbr/csir but csir/sbr (multiplied by a
precision factor). And do I understand correctly that, as sbr < csir,
this would be equal to the following ?

* fifo-sz >= image-width - sbr/csir * image-width

> + *
> + */
> +
> + sensor_bitrate /= TC358746_PRECISION;
> + n = csi_bitrate / sensor_bitrate;
> + tmp = (mbusfmt->width * TC358746_PRECISION) / n;
> + fifo_sz = mbusfmt->width - tmp;
> + fifo_sz *= fmt->bpp;
> + tc358746->vb_size = round_up(fifo_sz, 32);
> +
> +out:
> + dev_dbg(tc358746->sd.dev,
> + "Found FIFO size[bits]:%u -> aligned to size[bits]:%u\n",
> + fifo_sz, tc358746->vb_size);
> +
> + return tc358746->vb_size > TC358746_VB_MAX_SIZE ? -EINVAL : 0;
> +}
> +
> +static int tc358746_get_mbus_config(struct v4l2_subdev *sd, unsigned int pad,
> + struct v4l2_mbus_config *config)
> +{
> + struct tc358746 *tc358746 = to_tc358746(sd);
> +
> + if (pad != TC358746_SOURCE)
> + return -EINVAL;
> +
> + config->type = V4L2_MBUS_CSI2_DPHY;
> + config->bus.mipi_csi2 = tc358746->csi_vep.bus.mipi_csi2;
> +
> + return 0;
> +}
> +
> +int __maybe_unused

As reported by the buildbot, this should be static. Same for s_register.

> +tc358746_g_register(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg)
> +{
> + struct tc358746 *tc358746 = to_tc358746(sd);
> +
> + /* 32-bit registers starting from CLW_DPHYCONTTX */
> + reg->size = reg->reg < CLW_DPHYCONTTX_REG ? 2 : 4;
> +
> + if (pm_runtime_resume_and_get(sd->dev)) {
> + dev_err(sd->dev, "Failed to resume the device\n");
> + return 0;
> + }

Is there a point in powering the hardware on here if it's off, in order
to read a register that will have been reset due to the power cycle ?
pm_runtime_get_if_in_use() seems better. Same in .s_register().

> +
> + tc358746_read(tc358746, reg->reg, (u32 *)&reg->val);
> +
> + pm_runtime_mark_last_busy(sd->dev);
> + pm_runtime_put_sync_autosuspend(sd->dev);
> +
> + return 0;
> +}
> +
> +int __maybe_unused
> +tc358746_s_register(struct v4l2_subdev *sd, const struct v4l2_dbg_register *reg)
> +{
> + struct tc358746 *tc358746 = to_tc358746(sd);
> +
> + if (pm_runtime_resume_and_get(sd->dev)) {
> + dev_err(sd->dev, "Failed to resume the device\n");
> + return 0;
> + }
> +
> + tc358746_write(tc358746, (u32)reg->reg, (u32)reg->val);
> +
> + pm_runtime_mark_last_busy(sd->dev);
> + pm_runtime_put_sync_autosuspend(sd->dev);
> +
> + return 0;
> +}
> +
> +static const struct v4l2_subdev_core_ops tc358746_core_ops = {
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> + .g_register = tc358746_g_register,
> + .s_register = tc358746_s_register,
> +#endif
> +};
> +
> +static const struct v4l2_subdev_video_ops tc358746_video_ops = {
> + .s_stream = tc358746_s_stream,
> +};
> +
> +static const struct v4l2_subdev_pad_ops tc358746_pad_ops = {
> + .init_cfg = tc358746_init_cfg,
> + .enum_mbus_code = tc358746_enum_mbus_code,
> + .set_fmt = tc358746_set_fmt,
> + .get_fmt = v4l2_subdev_get_fmt,
> + .link_validate = tc358746_link_validate,
> + .get_mbus_config = tc358746_get_mbus_config,
> +};
> +
> +static const struct v4l2_subdev_ops tc358746_ops = {
> + .core = &tc358746_core_ops,
> + .video = &tc358746_video_ops,
> + .pad = &tc358746_pad_ops,
> +};
> +
> +static const struct media_entity_operations tc358746_entity_ops = {
> + .get_fwnode_pad = v4l2_subdev_get_fwnode_pad_1_to_1,
> + .link_validate = v4l2_subdev_link_validate,
> +};
> +
> +static int tc358746_mclk_enable(struct clk_hw *hw)
> +{
> + struct tc358746 *tc358746 = clk_hw_to_tc358746(hw);
> + unsigned int div;
> + u32 val;
> + int err;
> +
> + div = tc358746->mclk_postdiv / 2;
> + val = MCLK_HIGH(div - 1) | MCLK_LOW(div - 1);
> + dev_dbg(tc358746->sd.dev, "MCLKCTL: %u (0x%x)\n", val, val);
> + err = tc358746_write(tc358746, MCLKCTL_REG, val);
> + if (err)
> + return err;
> +
> + if (tc358746->mclk_prediv == 8)
> + val = MCLKDIV(MCLKDIV_8);
> + else if (tc358746->mclk_prediv == 4)
> + val = MCLKDIV(MCLKDIV_4);
> + else
> + val = MCLKDIV(MCLKDIV_2);
> +
> + dev_dbg(tc358746->sd.dev, "CLKCTL[MCLKDIV]: %u (0x%x)\n", val, val);
> + return tc358746_update_bits(tc358746, CLKCTL_REG, MCLKDIV_MASK, val);
> +}
> +
> +static void tc358746_mclk_disable(struct clk_hw *hw)
> +{
> + struct tc358746 *tc358746 = clk_hw_to_tc358746(hw);
> +
> + tc358746_write(tc358746, MCLKCTL_REG, 0);
> +}
> +
> +static long
> +tc358746_find_mclk_settings(struct tc358746 *tc358746, unsigned long mclk_rate)
> +{
> + unsigned long pll_rate = tc358746->pll_rate;
> + const unsigned char prediv[] = { 2, 4, 8 };
> + unsigned int mclk_prediv, mclk_postdiv;
> + struct device *dev = tc358746->sd.dev;
> + unsigned int postdiv, mclkdiv;
> + unsigned long best_mclk_rate;
> + unsigned int i;
> +
> + /*
> + * MCLK-Div
> + * -------------------´`---------------------
> + * ´ `
> + * +-------------+ +------------------------+
> + * | MCLK-PreDiv | | MCLK-PostDiv |
> + * PLL --> | (2/4/8) | --> | (mclk_low + mclk_high) | --> MCLK
> + * +-------------+ +------------------------+
> + *
> + * The register value of mclk_low/high is mclk_low/high+1, i.e.:
> + * mclk_low/high = 1 --> 2 MCLK-Ref Counts
> + * mclk_low/high = 255 --> 256 MCLK-Ref Counts == max.
> + * If mclk_low and mclk_high are 0 then MCLK is disabled.
> + *
> + * Keep it simple and support 50/50 duty cycles only for now,
> + * so the calc will be:
> + *
> + * MCLK = PLL / (MCLK-PreDiv * 2 * MCLK-PostDiv)
> + */
> +
> + if (mclk_rate == tc358746->mclk_rate)
> + return mclk_rate;
> +
> + /* Highest possible rate */
> + mclkdiv = pll_rate / mclk_rate;
> + if (mclkdiv <= 8) {
> + mclk_prediv = 2;
> + mclk_postdiv = 4;
> + best_mclk_rate = pll_rate / (2 * 4);
> + goto out;
> + }
> +
> + /* First check the prediv */
> + for (i = 0; i < ARRAY_SIZE(prediv); i++) {
> + postdiv = mclkdiv / prediv[i];
> +
> + if (postdiv % 2)
> + continue;
> +
> + if (postdiv >= 4 && postdiv <= 512) {
> + mclk_prediv = prediv[i];
> + mclk_postdiv = postdiv;
> + best_mclk_rate = pll_rate / (prediv[i] * postdiv);
> + goto out;
> + }
> + }
> +
> + /* No suitable prediv found, so try to adjust the postdiv */
> + for (postdiv = 4; postdiv <= 512; postdiv += 2) {
> + unsigned int pre;
> +
> + pre = mclkdiv / postdiv;
> + if (pre == 2 || pre == 4 || pre == 8) {
> + mclk_prediv = pre;
> + mclk_postdiv = postdiv;
> + best_mclk_rate = pll_rate / (pre * postdiv);
> + goto out;
> + }
> + }
> +
> + /* The MCLK <-> PLL gap is to high -> use largest possible div */
> + mclk_prediv = 8;
> + mclk_postdiv = 512;
> + best_mclk_rate = pll_rate / (8 * 512);
> +
> +out:
> + tc358746->mclk_prediv = mclk_prediv;
> + tc358746->mclk_postdiv = mclk_postdiv;
> + tc358746->mclk_rate = best_mclk_rate;
> +
> + if (best_mclk_rate != mclk_rate)
> + dev_warn(dev, "Request MCLK freq:%lu, found MCLK freq:%lu\n",
> + mclk_rate, best_mclk_rate);
> +
> + dev_dbg(dev, "Found MCLK settings: freq:%lu prediv:%u postdiv:%u\n",
> + best_mclk_rate, mclk_prediv, mclk_postdiv);
> +
> + return best_mclk_rate;
> +}
> +
> +unsigned long tc358746_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
> +{
> + struct tc358746 *tc358746 = clk_hw_to_tc358746(hw);
> + unsigned int prediv, postdiv;
> + u32 val;
> + int err;
> +
> + err = tc358746_read(tc358746, MCLKCTL_REG, &val);
> + if (err)
> + return 0;
> +
> + postdiv = FIELD_GET(MCLK_LOW_MASK, val) + 1;
> + postdiv += FIELD_GET(MCLK_HIGH_MASK, val) + 1;
> +
> + err = tc358746_read(tc358746, CLKCTL_REG, &val);
> + if (err)
> + return 0;
> +
> + prediv = FIELD_GET(MCLKDIV_MASK, val);
> + if (prediv == MCLKDIV_8)
> + prediv = 8;
> + else if (prediv == MCLKDIV_4)
> + prediv = 4;
> + else
> + prediv = 2;
> +
> + return tc358746->pll_rate / (prediv * postdiv);
> +}
> +
> +static long tc358746_mclk_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + struct tc358746 *tc358746 = clk_hw_to_tc358746(hw);
> +
> + *parent_rate = tc358746->pll_rate;
> +
> + return tc358746_find_mclk_settings(tc358746, rate);
> +}
> +
> +static int tc358746_mclk_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct tc358746 *tc358746 = clk_hw_to_tc358746(hw);
> +
> + tc358746_find_mclk_settings(tc358746, rate);
> +
> + return tc358746_mclk_enable(hw);
> +}
> +
> +static const struct clk_ops tc358746_mclk_ops = {
> + .enable = tc358746_mclk_enable,
> + .disable = tc358746_mclk_disable,
> + .recalc_rate = tc358746_recalc_rate,
> + .round_rate = tc358746_mclk_round_rate,
> + .set_rate = tc358746_mclk_set_rate,
> +};
> +
> +static int
> +tc358746_init_subdev(struct tc358746 *tc358746, struct i2c_client *client)
> +{
> + struct v4l2_subdev *sd;
> + int err;
> +
> + sd = &tc358746->sd;

You could initialize the variable when declaring it.

> + v4l2_i2c_subdev_init(sd, client, &tc358746_ops);
> + sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> + sd->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> + sd->entity.ops = &tc358746_entity_ops;
> +
> + tc358746->pads[TC358746_SINK].flags = MEDIA_PAD_FL_SINK;
> + tc358746->pads[TC358746_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
> + err = media_entity_pads_init(&sd->entity, TC358746_NR_PADS,
> + tc358746->pads);
> + if (err)
> + return err;
> +
> + err = v4l2_subdev_init_finalize(sd);
> + if (err)
> + media_entity_cleanup(&sd->entity);
> +
> + return err;
> +}
> +
> +static int
> +tc358746_init_output_port(struct tc358746 *tc358746, unsigned long refclk)
> +{
> + struct device *dev = tc358746->sd.dev;
> + struct v4l2_fwnode_endpoint *vep;
> + unsigned long csi_link_rate;
> + struct fwnode_handle *ep;
> + unsigned char csi_lanes;
> + int err;
> +
> + ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), TC358746_SOURCE,
> + 0, 0);
> + if (!ep) {
> + dev_err(dev, "Missing endpoint node\n");
> + return -EINVAL;
> + }
> +
> + /* Currently we only support 'parallel in' -> 'csi out' */
> + vep = &tc358746->csi_vep;
> + vep->bus_type = V4L2_MBUS_CSI2_DPHY;
> + err = v4l2_fwnode_endpoint_alloc_parse(ep, vep);
> + fwnode_handle_put(ep);
> + if (err) {
> + dev_err(dev, "Failed to parse source endpoint\n");
> + return err;
> + }
> +
> + csi_lanes = vep->bus.mipi_csi2.num_data_lanes;
> + if (csi_lanes == 0 || csi_lanes > 4 ||
> + vep->nr_of_link_frequencies == 0) {
> + dev_err(dev, "error: Invalid CSI-2 settings\n");
> + err = -EINVAL;
> + goto err;
> + }
> +
> + /* TODO: Add support to handle multiple link frequencies */
> + csi_link_rate = (unsigned long)vep->link_frequencies[0];
> + tc358746->pll_rate = tc358746_find_pll_settings(tc358746, refclk,
> + csi_link_rate * 2);
> + if (!tc358746->pll_rate) {
> + err = -EINVAL;
> + goto err;
> + }
> +
> + err = phy_mipi_dphy_get_default_config_for_hsclk(tc358746->pll_rate,
> + csi_lanes, &tc358746->dphy_cfg);
> + if (err)
> + goto err;
> +
> + tc358746->vb_size = TC358746_VB_DEFAULT_SIZE;
> +
> + return 0;
> +
> +err:
> + v4l2_fwnode_endpoint_free(vep);
> +
> + return err;
> +}
> +
> +static int tc358746_init_hw(struct tc358746 *tc358746)
> +{
> + struct device *dev = tc358746->sd.dev;
> + unsigned int chipid;
> + u32 val;
> + int err;
> +
> + err = pm_runtime_resume_and_get(dev);
> + if (err < 0) {
> + dev_err(dev, "Failed to resume the device\n");
> + return err;
> + }
> +
> + /* Ensure that CSI interface is put into LP-11 state */
> + err = tc358746_sw_reset(tc358746);
> + if (err) {
> + pm_runtime_put_noidle(dev);

Don't you need a regular put (possibly with autosuspend) here ?
Otherwise a reset failure will decrement the runtime PM use count but
leave the decide powered.

> + dev_err(dev, "Failed to reset the device\n");
> + return err;
> + }
> +
> + err = tc358746_read(tc358746, CHIPID_REG, &val);
> + pm_runtime_mark_last_busy(dev);
> + pm_runtime_put_sync_autosuspend(dev);
> + if (err) {
> + dev_err(dev, "Failed to read chipid\n");

How about moving the read failure message to tc358746_read() ? It's
useful to get error messages for all failures, not just this one. Or do
we get a message from regmap already ? If we do, then we could just drop
this.

> + return -ENODEV;
> + }
> +
> + chipid = FIELD_GET(CHIPID, val);
> + if (chipid != 0x44) {
> + dev_err(dev, "Invalid chipid 0x%02x\n", chipid);
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> +static int tc358746_setup_mclk_provider(struct tc358746 *tc358746)

I'd move this right after tc358746_mclk_ops as they're related.

> +{
> + struct clk_init_data mclk_initdata = { };
> + struct device *dev = tc358746->sd.dev;
> + const char *mclk_name;
> + int err;
> +
> + /* MCLK clk provider support is optional */
> + if (!device_property_present(dev, "#clock-cells"))
> + return 0;
> +
> + /* Init to highest possibel MCLK */
> + tc358746->mclk_postdiv = 512;
> + tc358746->mclk_prediv = 8;
> +
> + mclk_name = "tc358746-mclk";
> + device_property_read_string(dev, "clock-output-names",
> + &mclk_name);

This holds on a single line.

> +
> + mclk_initdata.name = mclk_name;
> + mclk_initdata.ops = &tc358746_mclk_ops;
> + tc358746->mclk_hw.init = &mclk_initdata;
> +
> + err = devm_clk_hw_register(dev, &tc358746->mclk_hw);
> + if (err) {
> + dev_err(dev, "Failed to register mclk provider\n");
> + return err;
> + }
> +
> + err = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
> + &tc358746->mclk_hw);
> + if (err)
> + dev_err(dev, "Failed to add mclk provider\n");
> +
> + return err;
> +}
> +
> +static int tc358746_init_controls(struct tc358746 *tc358746)
> +{
> + u64 *link_frequencies = tc358746->csi_vep.link_frequencies;
> + struct v4l2_ctrl *ctrl;
> + int err;
> +
> + err = v4l2_ctrl_handler_init(&tc358746->ctrl_hdl, 1);
> + if (err)
> + return err;
> +
> + ctrl = v4l2_ctrl_new_int_menu(&tc358746->ctrl_hdl, NULL,
> + V4L2_CID_LINK_FREQ, 0, 0,

Shouldn't the max argument be set to the number of items minus 1 ?

> + link_frequencies);
> + if (ctrl)
> + ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> + tc358746->sd.ctrl_handler = &tc358746->ctrl_hdl;
> + if (tc358746->ctrl_hdl.error)
> + return tc358746->ctrl_hdl.error;

You need to call v4l2_ctrl_handler_free() in the failure paths.

> +
> + return v4l2_ctrl_handler_setup(&tc358746->ctrl_hdl);

This can be skipped I think, as the only supported control is read-only.

> +}
> +
> +static int tc358746_notify_bound(struct v4l2_async_notifier *notifier,
> + struct v4l2_subdev *sd,
> + struct v4l2_async_subdev *asd)
> +{
> + struct tc358746 *tc358746 =
> + container_of(notifier, struct tc358746, notifier);
> + struct media_pad *sink = &tc358746->pads[TC358746_SINK];
> +
> + return v4l2_create_fwnode_links_to_pad(sd, sink, MEDIA_LNK_FL_ENABLED);

I'd make the link immutable too, as only one source subdev is supported.

> +}
> +
> +static const struct v4l2_async_notifier_operations tc358746_notify_ops = {
> + .bound = tc358746_notify_bound,
> +};
> +
> +static int tc358746_async_register(struct tc358746 *tc358746)
> +{
> + struct v4l2_fwnode_endpoint vep = {
> + .bus_type = V4L2_MBUS_PARALLEL,
> + };
> + struct v4l2_async_subdev *asd;
> + struct fwnode_handle *ep;
> + int err;
> +
> + ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(tc358746->sd.dev),
> + TC358746_SINK, 0, 0);
> + if (!ep)
> + return -ENOTCONN;
> +
> + err = v4l2_fwnode_endpoint_parse(ep, &vep);
> + if (err) {
> + fwnode_handle_put(ep);
> + return err;
> + }
> +
> + v4l2_async_nf_init(&tc358746->notifier);
> + asd = v4l2_async_nf_add_fwnode_remote(&tc358746->notifier, ep,
> + struct v4l2_async_subdev);
> + if (IS_ERR(asd)) {
> + fwnode_handle_put(ep);

You can move this before the error check and drop the next one.

> + return PTR_ERR(asd);

Shouldn't v4l2_async_nf_cleanup() be called here ?

> + }
> +
> + fwnode_handle_put(ep);
> +
> + tc358746->notifier.ops = &tc358746_notify_ops;
> +
> + err = v4l2_async_subdev_nf_register(&tc358746->sd, &tc358746->notifier);
> + if (err) {
> + v4l2_async_nf_cleanup(&tc358746->notifier);
> + return err;
> + }
> +
> + tc358746->sd.fwnode = fwnode_graph_get_endpoint_by_id(
> + dev_fwnode(tc358746->sd.dev), TC358746_SOURCE, 0, 0);

Where is this reference dropped ?

> +
> + err = v4l2_async_register_subdev(&tc358746->sd);
> + if (err) {
> + v4l2_async_nf_unregister(&tc358746->notifier);
> + v4l2_async_nf_cleanup(&tc358746->notifier);
> + }
> +
> + return err;

return 0;

> +}
> +
> +static int tc358746_probe(struct i2c_client *client)
> +{
> + struct device *dev = &client->dev;
> + struct tc358746 *tc358746;
> + unsigned long refclk;
> + unsigned int i;
> + int err;
> +
> + tc358746 = devm_kzalloc(&client->dev, sizeof(*tc358746), GFP_KERNEL);
> + if (!tc358746)
> + return -ENOMEM;
> +
> + tc358746->regmap = devm_regmap_init_i2c(client, &tc358746_regmap_config);
> + if (IS_ERR(tc358746->regmap))
> + return dev_err_probe(dev, PTR_ERR(tc358746->regmap),
> + "Failed to init regmap\n");
> +
> + tc358746->refclk = devm_clk_get(dev, "refclk");
> + if (IS_ERR(tc358746->refclk))
> + return dev_err_probe(dev, PTR_ERR(tc358746->refclk),
> + "Failed to get refclk\n");
> +
> + err = clk_prepare_enable(tc358746->refclk);
> + if (err)
> + return dev_err_probe(dev, err,
> + "Failed to enable refclk\n");
> +
> + refclk = clk_get_rate(tc358746->refclk);
> + clk_disable_unprepare(tc358746->refclk);
> +
> + if (refclk < 6 * MHZ || refclk > 40 * MHZ)
> + return dev_err_probe(dev, -EINVAL, "Invalid refclk range\n");
> +
> + for (i = 0; i < ARRAY_SIZE(tc358746_supplies); i++)
> + tc358746->supplies[i].supply = tc358746_supplies[i];
> +
> + err = devm_regulator_bulk_get(dev, ARRAY_SIZE(tc358746_supplies),
> + tc358746->supplies);
> + if (err)
> + return dev_err_probe(dev, err, "Failed to get supplies\n");
> +
> + tc358746->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(tc358746->reset_gpio))
> + return dev_err_probe(dev, PTR_ERR(tc358746->reset_gpio),
> + "Failed to get reset-gpios\n");
> +
> + err = tc358746_init_subdev(tc358746, client);
> + if (err)
> + return dev_err_probe(dev, err, "Failed to init subdev\n");
> +
> + err = tc358746_init_output_port(tc358746, refclk);
> + if (err)
> + goto err_subdev;
> +
> + /*
> + * Keep this order since we need the output port link-frequencies
> + * information.
> + */
> + err = tc358746_init_controls(tc358746);
> + if (err)
> + goto err_fwnode;
> +
> + dev_set_drvdata(dev, tc358746);
> + pm_runtime_set_autosuspend_delay(dev, 200);

200ms may be a bit short for a complete stop/restart cycle. How about
1s ?

> + pm_runtime_use_autosuspend(dev);
> + pm_runtime_enable(dev);
> +
> + err = tc358746_init_hw(tc358746);
> + if (err)
> + goto err_pm;
> +
> + err = tc358746_setup_mclk_provider(tc358746);
> + if (err)
> + goto err_pm;
> +
> + err = tc358746_async_register(tc358746);
> + if (err < 0)
> + goto err_pm;
> +
> + dev_dbg(dev, "%s found @ 0x%x (%s)\n", client->name,
> + client->addr, client->adapter->name);
> +
> + return 0;
> +
> +err_pm:
> + pm_runtime_disable(dev);
> + pm_runtime_set_suspended(dev);
> + pm_runtime_dont_use_autosuspend(dev);
> + v4l2_ctrl_handler_free(&tc358746->ctrl_hdl);
> +err_fwnode:
> + v4l2_fwnode_endpoint_free(&tc358746->csi_vep);
> +err_subdev:
> + v4l2_subdev_cleanup(&tc358746->sd);
> + media_entity_cleanup(&tc358746->sd.entity);
> +
> + return err;
> +}
> +
> +static int tc358746_remove(struct i2c_client *client)
> +{
> + struct v4l2_subdev *sd = i2c_get_clientdata(client);
> + struct tc358746 *tc358746 = to_tc358746(sd);
> +
> + v4l2_subdev_cleanup(sd);
> + v4l2_ctrl_handler_free(&tc358746->ctrl_hdl);
> + v4l2_fwnode_endpoint_free(&tc358746->csi_vep);
> + v4l2_async_nf_unregister(&tc358746->notifier);
> + v4l2_async_nf_cleanup(&tc358746->notifier);
> + v4l2_async_unregister_subdev(sd);
> + media_entity_cleanup(&sd->entity);
> +
> + pm_runtime_disable(sd->dev);
> + pm_runtime_set_suspended(sd->dev);
> + pm_runtime_dont_use_autosuspend(sd->dev);
> +
> + return 0;
> +}
> +
> +static int tc358746_suspend(struct device *dev)
> +{
> + struct tc358746 *tc358746 = dev_get_drvdata(dev);
> + int err;
> +
> + clk_disable_unprepare(tc358746->refclk);
> +
> + err = regulator_bulk_disable(ARRAY_SIZE(tc358746_supplies),
> + tc358746->supplies);
> + if (err)
> + clk_prepare_enable(tc358746->refclk);
> +
> + return err;
> +}
> +
> +static int tc358746_resume(struct device *dev)
> +{
> + struct tc358746 *tc358746 = dev_get_drvdata(dev);
> + int err;
> +
> + gpiod_set_value(tc358746->reset_gpio, 1);
> +
> + err = regulator_bulk_enable(ARRAY_SIZE(tc358746_supplies),
> + tc358746->supplies);
> + if (err)
> + return err;
> +
> + /* min. 200ns */
> + usleep_range(10, 20);
> +
> + gpiod_set_value(tc358746->reset_gpio, 0);
> +
> + err = clk_prepare_enable(tc358746->refclk);
> + if (err)
> + goto err;
> +
> + /* min. 700us ... 1ms */
> + usleep_range(1000, 1500);
> +
> + /*
> + * Enable the PLL here since it can be called by the clk-framework or by
> + * the .s_stream() callback. So this is the common place for both.
> + */
> + err = tc358746_apply_pll_config(tc358746);
> + if (err)
> + goto err_clk;
> +
> + return 0;
> +
> +err_clk:
> + clk_disable_unprepare(tc358746->refclk);
> +err:
> + regulator_bulk_disable(ARRAY_SIZE(tc358746_supplies),
> + tc358746->supplies);
> + return err;
> +}
> +
> +DEFINE_RUNTIME_DEV_PM_OPS(tc358746_pm_ops, tc358746_suspend,
> + tc358746_resume, NULL);
> +
> +static const struct of_device_id __maybe_unused tc358746_of_match[] = {
> + { .compatible = "toshiba,tc358746" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, tc358746_of_match);
> +
> +static struct i2c_driver tc358746_driver = {
> + .driver = {
> + .name = "tc358746",
> + .pm = pm_ptr(&tc358746_pm_ops),
> + .of_match_table = tc358746_of_match,
> + },
> + .probe_new = tc358746_probe,
> + .remove = tc358746_remove,
> +};
> +
> +module_i2c_driver(tc358746_driver);
> +
> +MODULE_DESCRIPTION("Toshiba TC358746 Parallel to CSI-2 bridge driver");
> +MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>");
> +MODULE_LICENSE("GPL");

--
Regards,

Laurent Pinchart

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