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Subject[PATCH v6 1/4] phy: cadence: Add Cadence D-PHY Rx driver
Date
The Cadence D-PHY can be configured in Tx (DSI) mode or Rx (CSI) mode.
Both modes have a different programming sequence and share little among
them. In addition, a PHY configured in Tx mode cannot be used in Rx mode
and vice versa. For this reason, create a separate driver for the Rx
mode to make it easier to read and maintain.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>

---

Changes in v6:
- Move to a separate driver.

Changes in v5:
- Use the new cdns_dphy_info to specify PHY ops.
- Re-order include in alphabetical order.
- Make bands const.
- Drop num_bands.
- Make i, lanes unsigned.
- Drop the maximum check in cdns_dphy_rx_get_band_ctrl(). Let the loop
complete and return -EOPNOTSUPP when we reach the end.
- Drop the "rate < bands[i].min_rate" check since the bands are in
ascending order.
- Move data_lane_ctrl to start of function and make it static const.

Changes in v4:
- Drop the submode parts. Use a different compatible for the Rx ops.
- Make bands and num_bands static.

Changes in v3:
- Use a table to select the band.
- Use a table to poll the data lane ready bits.
- Multiply the DPHY HS clock rate by 2 to get the bit rate since the
clock is DDR.

drivers/phy/cadence/Kconfig | 8 +
drivers/phy/cadence/Makefile | 1 +
drivers/phy/cadence/cdns-dphy-rx.c | 250 +++++++++++++++++++++++++++++
3 files changed, 259 insertions(+)
create mode 100644 drivers/phy/cadence/cdns-dphy-rx.c

diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
index a62910ff5591..1adde2d99ae7 100644
--- a/drivers/phy/cadence/Kconfig
+++ b/drivers/phy/cadence/Kconfig
@@ -22,6 +22,14 @@ config PHY_CADENCE_DPHY
system. If M is selected, the module will be called
cdns-dphy.

+config PHY_CADENCE_DPHY_RX
+ tristate "Cadence D-PHY Rx Support"
+ depends on HAS_IOMEM && OF
+ select GENERIC_PHY
+ select GENERIC_PHY_MIPI_DPHY
+ help
+ Support for Cadence D-PHY in Rx configuration.
+
config PHY_CADENCE_SIERRA
tristate "Cadence Sierra PHY Driver"
depends on OF && HAS_IOMEM && RESET_CONTROLLER
diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
index 26e16bd34efe..e17f035ddece 100644
--- a/drivers/phy/cadence/Makefile
+++ b/drivers/phy/cadence/Makefile
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_PHY_CADENCE_TORRENT) += phy-cadence-torrent.o
obj-$(CONFIG_PHY_CADENCE_DPHY) += cdns-dphy.o
+obj-$(CONFIG_PHY_CADENCE_DPHY_RX) += cdns-dphy-rx.o
obj-$(CONFIG_PHY_CADENCE_SIERRA) += phy-cadence-sierra.o
obj-$(CONFIG_PHY_CADENCE_SALVO) += phy-cadence-salvo.o
diff --git a/drivers/phy/cadence/cdns-dphy-rx.c b/drivers/phy/cadence/cdns-dphy-rx.c
new file mode 100644
index 000000000000..fb75e645e662
--- /dev/null
+++ b/drivers/phy/cadence/cdns-dphy-rx.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Texas Instruments Incorporated - https://www.ti.com/
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/phy/phy.h>
+#include <linux/phy/phy-mipi-dphy.h>
+#include <linux/platform_device.h>
+
+#define DPHY_PMA_CMN(reg) (reg)
+#define DPHY_PCS(reg) (0xb00 + (reg))
+#define DPHY_ISO(reg) (0xc00 + (reg))
+
+#define DPHY_CMN_SSM DPHY_PMA_CMN(0x20)
+#define DPHY_CMN_RX_MODE_EN BIT(10)
+#define DPHY_CMN_RX_BANDGAP_TIMER_MASK GENMASK(8, 1)
+#define DPHY_CMN_SSM_EN BIT(0)
+
+#define DPHY_CMN_RX_BANDGAP_TIMER 0x14
+
+#define DPHY_BAND_CFG DPHY_PCS(0x0)
+#define DPHY_BAND_CFG_RIGHT_BAND GENMASK(9, 5)
+#define DPHY_BAND_CFG_LEFT_BAND GENMASK(4, 0)
+
+#define DPHY_POWER_ISLAND_EN_DATA DPHY_PCS(0x8)
+#define DPHY_POWER_ISLAND_EN_DATA_VAL 0xaaaaaaaa
+
+#define DPHY_POWER_ISLAND_EN_CLK DPHY_PCS(0xc)
+#define DPHY_POWER_ISLAND_EN_CLK_VAL 0xaa
+
+#define DPHY_ISO_CL_CTRL_L DPHY_ISO(0x10)
+#define DPHY_ISO_DL_CTRL_L0 DPHY_ISO(0x14)
+#define DPHY_ISO_DL_CTRL_L1 DPHY_ISO(0x20)
+#define DPHY_ISO_DL_CTRL_L2 DPHY_ISO(0x30)
+#define DPHY_ISO_DL_CTRL_L3 DPHY_ISO(0x3c)
+
+#define DPHY_ISO_LANE_READY_BIT 0
+#define DPHY_ISO_LANE_READY_TIMEOUT_MS 100UL
+
+#define DPHY_LANES_MIN 1
+#define DPHY_LANES_MAX 4
+
+struct cdns_dphy_rx {
+ void __iomem *regs;
+ struct device *dev;
+ struct phy *phy;
+};
+
+struct cdns_dphy_rx_band {
+ /* Rates are in Mbps. */
+ unsigned int min_rate;
+ unsigned int max_rate;
+};
+
+/* Order of bands is important since the index is the band number. */
+static const struct cdns_dphy_rx_band bands[] = {
+ {80, 100}, {100, 120}, {120, 160}, {160, 200}, {200, 240},
+ {240, 280}, {280, 320}, {320, 360}, {360, 400}, {400, 480},
+ {480, 560}, {560, 640}, {640, 720}, {720, 800}, {800, 880},
+ {880, 1040}, {1040, 1200}, {1200, 1350}, {1350, 1500}, {1500, 1750},
+ {1750, 2000}, {2000, 2250}, {2250, 2500}
+};
+
+static int cdns_dphy_rx_power_on(struct phy *phy)
+{
+ struct cdns_dphy_rx *dphy = phy_get_drvdata(phy);
+
+ /* Start RX state machine. */
+ writel(DPHY_CMN_SSM_EN | DPHY_CMN_RX_MODE_EN |
+ FIELD_PREP(DPHY_CMN_RX_BANDGAP_TIMER_MASK,
+ DPHY_CMN_RX_BANDGAP_TIMER),
+ dphy->regs + DPHY_CMN_SSM);
+
+ return 0;
+}
+
+static int cdns_dphy_rx_power_off(struct phy *phy)
+{
+ struct cdns_dphy_rx *dphy = phy_get_drvdata(phy);
+
+ writel(0, dphy->regs + DPHY_CMN_SSM);
+
+ return 0;
+}
+
+static int cdns_dphy_rx_get_band_ctrl(unsigned long hs_clk_rate)
+{
+ unsigned int rate, i;
+
+ rate = hs_clk_rate / 1000000UL;
+ /* Since CSI-2 clock is DDR, the bit rate is twice the clock rate. */
+ rate *= 2;
+
+ if (rate < bands[0].min_rate)
+ return -EOPNOTSUPP;
+
+ for (i = 0; i < ARRAY_SIZE(bands); i++) {
+ if (rate < bands[i].max_rate)
+ return i;
+ }
+
+ return -EOPNOTSUPP;
+}
+
+static int cdns_dphy_rx_wait_for_bit(void __iomem *addr, unsigned int bit)
+{
+ u32 val;
+
+ return readl_relaxed_poll_timeout(addr, val, val & BIT(bit), 10,
+ DPHY_ISO_LANE_READY_TIMEOUT_MS * 1000);
+}
+
+static int cdns_dphy_rx_wait_lane_ready(struct cdns_dphy_rx *dphy,
+ unsigned int lanes)
+{
+ static const u32 data_lane_ctrl[] = {DPHY_ISO_DL_CTRL_L0,
+ DPHY_ISO_DL_CTRL_L1,
+ DPHY_ISO_DL_CTRL_L2,
+ DPHY_ISO_DL_CTRL_L3};
+ void __iomem *reg = dphy->regs;
+ unsigned int i;
+ int ret;
+
+ /* Data lanes. Minimum one lane is mandatory. */
+ if (lanes < DPHY_LANES_MIN || lanes > DPHY_LANES_MAX)
+ return -EINVAL;
+
+ /* Clock lane */
+ ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_CL_CTRL_L,
+ DPHY_ISO_LANE_READY_BIT);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < lanes; i++) {
+ ret = cdns_dphy_rx_wait_for_bit(reg + data_lane_ctrl[i],
+ DPHY_ISO_LANE_READY_BIT);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int cdns_dphy_rx_configure(struct phy *phy,
+ union phy_configure_opts *opts)
+{
+ struct cdns_dphy_rx *dphy = phy_get_drvdata(phy);
+ unsigned int reg;
+ int band_ctrl, ret;
+
+ band_ctrl = cdns_dphy_rx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+ if (band_ctrl < 0)
+ return band_ctrl;
+
+ reg = FIELD_PREP(DPHY_BAND_CFG_LEFT_BAND, band_ctrl) |
+ FIELD_PREP(DPHY_BAND_CFG_RIGHT_BAND, band_ctrl);
+ writel(reg, dphy->regs + DPHY_BAND_CFG);
+
+ /*
+ * Set the required power island phase 2 time. This is mandated by DPHY
+ * specs.
+ */
+ reg = DPHY_POWER_ISLAND_EN_DATA_VAL;
+ writel(reg, dphy->regs + DPHY_POWER_ISLAND_EN_DATA);
+ reg = DPHY_POWER_ISLAND_EN_CLK_VAL;
+ writel(reg, dphy->regs + DPHY_POWER_ISLAND_EN_CLK);
+
+ ret = cdns_dphy_rx_wait_lane_ready(dphy, opts->mipi_dphy.lanes);
+ if (ret) {
+ dev_err(dphy->dev, "DPHY wait for lane ready timeout\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int cdns_dphy_rx_validate(struct phy *phy, enum phy_mode mode,
+ int submode, union phy_configure_opts *opts)
+{
+ int ret;
+
+ if (mode != PHY_MODE_MIPI_DPHY)
+ return -EINVAL;
+
+ ret = cdns_dphy_rx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+ if (ret < 0)
+ return ret;
+
+ return phy_mipi_dphy_config_validate(&opts->mipi_dphy);
+}
+
+static const struct phy_ops cdns_dphy_rx_ops = {
+ .power_on = cdns_dphy_rx_power_on,
+ .power_off = cdns_dphy_rx_power_off,
+ .configure = cdns_dphy_rx_configure,
+ .validate = cdns_dphy_rx_validate,
+};
+
+static int cdns_dphy_rx_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct phy_provider *provider;
+ struct cdns_dphy_rx *dphy;
+
+ dphy = devm_kzalloc(dev, sizeof(*dphy), GFP_KERNEL);
+ if (!dphy)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, dphy);
+ dphy->dev = dev;
+
+ dphy->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(dphy->regs))
+ return PTR_ERR(dphy->regs);
+
+ dphy->phy = devm_phy_create(dev, NULL, &cdns_dphy_rx_ops);
+ if (IS_ERR(dphy->phy)) {
+ dev_err(dev, "Failed to create PHY: %d\n", PTR_ERR(dphy->phy));
+ return PTR_ERR(dphy->phy);
+ }
+
+ phy_set_drvdata(dphy->phy, dphy);
+ provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+ return PTR_ERR_OR_ZERO(provider);
+}
+
+static const struct of_device_id cdns_dphy_rx_of_match[] = {
+ { .compatible = "cdns,dphy-rx" },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cdns_dphy_rx_of_match);
+
+static struct platform_driver cdns_dphy_rx_platform_driver = {
+ .probe = cdns_dphy_rx_probe,
+ .driver = {
+ .name = "cdns-mipi-dphy-rx",
+ .of_match_table = cdns_dphy_rx_of_match,
+ },
+};
+module_platform_driver(cdns_dphy_rx_platform_driver);
+
+MODULE_AUTHOR("Pratyush Yadav <p.yadav@ti.com>");
+MODULE_DESCRIPTION("Cadence D-PHY Rx Driver");
+MODULE_LICENSE("GPL v2");
--
2.33.1.835.ge9e5ba39a7
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