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SubjectRe: [PATCH v1 1/4] fbtft: Unorphan the driver
From
Hi

Am 31.01.22 um 09:29 schrieb Javier Martinez Canillas:
> On 1/26/22 15:15, Javier Martinez Canillas wrote:
>> On 1/26/22 15:10, Andy Shevchenko wrote:
>>> On Wed, Jan 26, 2022 at 04:08:32PM +0200, Andy Shevchenko wrote:
>>>> On Wed, Jan 26, 2022 at 02:46:08PM +0100, Javier Martinez Canillas wrote:
>>>>> On 1/26/22 14:12, Andy Shevchenko wrote:
>>>
>>> ...
>>>
>>>>> I've just bought a SSD1306 (I2C) based one and will attempt to write a DRM
>>>>> driver using drivers/staging/fbtft/fb_ssd1306.c as a reference.
>>>>
>>>> You should take ssd1307fb.c instead. And basically create a MIPI based driver
>>>> for I2C. Then we won't go same road again for other similar devices.
>>>
>>> For the record it supports your device:
>>>
>>> static const struct i2c_device_id ssd1307fb_i2c_id[] = {
>>> { "ssd1305fb", 0 },
>>> { "ssd1306fb", 0 },
>>> { "ssd1307fb", 0 },
>>> { "ssd1309fb", 0 },
>>>
>>>
>>
>> Thanks a lot for the pointer. I was only looking at drivers/staging
>> and didn't check drivers/video. I'll try to convert that one then
>> once I get the display.
>>
>
> I got some time this weekend and was able to port the ssd1306 fbdev driver
> to DRM [0]. I'm not that familiar with the simple display pipe helpers, so
> there may be some wrong things there. But it does work and all the fbtests
> from https://git.kernel.org/pub/scm/linux/kernel/git/geert/fbtest.git pass.

Awesome!

>
> There are some hacks in the driver though. For example it exposes an XRGB8888
> format even thought the OLED display is monochromatic and has 1 bit per pixel.
>
> The driver then goes and converts the XRGB8888 pixels first to grayscale and
> then to reverse mono. I took that idea from the repaper driver but that gives
> us the multiple copies that Geert was complaining about.

This requires to update the console code for 1-bit BW output. The fbcon
side already supports this AFAIK. DRM's fbdev needs a few more branches
and something like a DRM_FORMAT_C1 fourcc. The XRGB8888 is really a
userspace requirement that is imposed by modern desktops. If DRM's
console has been updated, you could leave it out entirely.

I could imagine that some simple userspace, such as Weston, comes with
support for palette formats and BW. Or there could be an entirely
separate program that puts graphics onto these displays.

Best regards
Thomas

>
> Another hack is that I am just hardcoding the {width, height}_mm, but I don't
> know what DPI could be used for these panels nor how I could calculate the mm.
>
> Best regards,
> Javier
>
> [0]:
> From 5ec4b468b66022d4c48ae6bec8a68926a01a6785 Mon Sep 17 00:00:00 2001
> From: Javier Martinez Canillas <javierm@redhat.com>
> Date: Sun, 30 Jan 2022 12:16:34 +0100
> Subject: [RFC] drm/tiny: Add driver for Solomon SSD130X OLED displays
>
> Add a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon OLED
> controllers that can be programmed via an I2C interface. This is a port
> of the ssd1307fb driver that already supports these devices.
>
> A Device Tree binding is not added because the DRM driver is compatible
> with the existing binding for the ssd1307fb driver.
>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> ---
> MAINTAINERS | 7 +
> drivers/gpu/drm/tiny/Kconfig | 12 +
> drivers/gpu/drm/tiny/Makefile | 1 +
> drivers/gpu/drm/tiny/ssd130x.c | 944 +++++++++++++++++++++++++++++++++
> 4 files changed, 964 insertions(+)
> create mode 100644 drivers/gpu/drm/tiny/ssd130x.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d03ad8da1f36..87334676ce07 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6102,6 +6102,13 @@ T: git git://anongit.freedesktop.org/drm/drm-misc
> F: Documentation/devicetree/bindings/display/repaper.txt
> F: drivers/gpu/drm/tiny/repaper.c
>
> +DRM DRIVER FOR SOLOMON SSD130X DISPLAYS
> +M: Javier Martinez Canillas <javierm@redhat.com>
> +S: Maintained
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +F: Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> +F: drivers/gpu/drm/tiny/ssd130x.c
> +
> DRM DRIVER FOR QEMU'S CIRRUS DEVICE
> M: Dave Airlie <airlied@redhat.com>
> M: Gerd Hoffmann <kraxel@redhat.com>
> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
> index 712e0004e96e..358ceb7354f5 100644
> --- a/drivers/gpu/drm/tiny/Kconfig
> +++ b/drivers/gpu/drm/tiny/Kconfig
> @@ -157,6 +157,18 @@ config TINYDRM_REPAPER
>
> If M is selected the module will be called repaper.
>
> +config TINYDRM_SSD130X
> + tristate "DRM support for Solomon SSD130X OLED displays"
> + depends on DRM && OF && I2C
> + select DRM_KMS_HELPER
> + select DRM_GEM_SHMEM_HELPER
> + select BACKLIGHT_CLASS_DEVICE
> + help
> + DRM driver for the SSD1305, SSD1306, SSD1307 and SSD1309 Solomon
> + OLED controllers that can be programmed via an I2C interface.
> +
> + If M is selected the module will be called ssd130x.
> +
> config TINYDRM_ST7586
> tristate "DRM support for Sitronix ST7586 display panels"
> depends on DRM && SPI
> diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
> index 5d5505d40e7b..93a1d70155f0 100644
> --- a/drivers/gpu/drm/tiny/Makefile
> +++ b/drivers/gpu/drm/tiny/Makefile
> @@ -12,5 +12,6 @@ obj-$(CONFIG_TINYDRM_ILI9341) += ili9341.o
> obj-$(CONFIG_TINYDRM_ILI9486) += ili9486.o
> obj-$(CONFIG_TINYDRM_MI0283QT) += mi0283qt.o
> obj-$(CONFIG_TINYDRM_REPAPER) += repaper.o
> +obj-$(CONFIG_TINYDRM_SSD130X) += ssd130x.o
> obj-$(CONFIG_TINYDRM_ST7586) += st7586.o
> obj-$(CONFIG_TINYDRM_ST7735R) += st7735r.o
> diff --git a/drivers/gpu/drm/tiny/ssd130x.c b/drivers/gpu/drm/tiny/ssd130x.c
> new file mode 100644
> index 000000000000..88d88caeb37d
> --- /dev/null
> +++ b/drivers/gpu/drm/tiny/ssd130x.c
> @@ -0,0 +1,944 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * DRM driver for Solomon SSD130X OLED displays
> + *
> + * Copyright 2022 Red Hat Inc.
> + *
> + * Based on drivers/video/fbdev/ssd1307fb.c
> + * Copyright 2012 Free Electrons
> + *
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/pwm.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_damage_helper.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_fb_cma_helper.h>
> +#include <drm/drm_fb_helper.h>
> +#include <drm/drm_format_helper.h>
> +#include <drm/drm_gem_atomic_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
> +#include <drm/drm_managed.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_rect.h>
> +#include <drm/drm_probe_helper.h>
> +#include <drm/drm_simple_kms_helper.h>
> +
> +#define DRIVER_NAME "ssd130x"
> +#define DRIVER_DESC "DRM driver for Solomon SSD130X OLED displays"
> +#define DRIVER_DATE "20220130"
> +#define DRIVER_MAJOR 1
> +#define DRIVER_MINOR 0
> +
> +#define SSD130X_DATA 0x40
> +#define SSD130X_COMMAND 0x80
> +
> +#define SSD130X_SET_ADDRESS_MODE 0x20
> +#define SSD130X_SET_ADDRESS_MODE_HORIZONTAL (0x00)
> +#define SSD130X_SET_ADDRESS_MODE_VERTICAL (0x01)
> +#define SSD130X_SET_ADDRESS_MODE_PAGE (0x02)
> +#define SSD130X_SET_COL_RANGE 0x21
> +#define SSD130X_SET_PAGE_RANGE 0x22
> +#define SSD130X_CONTRAST 0x81
> +#define SSD130X_SET_LOOKUP_TABLE 0x91
> +#define SSD130X_CHARGE_PUMP 0x8d
> +#define SSD130X_SEG_REMAP_ON 0xa1
> +#define SSD130X_DISPLAY_OFF 0xae
> +#define SSD130X_SET_MULTIPLEX_RATIO 0xa8
> +#define SSD130X_DISPLAY_ON 0xaf
> +#define SSD130X_START_PAGE_ADDRESS 0xb0
> +#define SSD130X_SET_DISPLAY_OFFSET 0xd3
> +#define SSD130X_SET_CLOCK_FREQ 0xd5
> +#define SSD130X_SET_AREA_COLOR_MODE 0xd8
> +#define SSD130X_SET_PRECHARGE_PERIOD 0xd9
> +#define SSD130X_SET_COM_PINS_CONFIG 0xda
> +#define SSD130X_SET_VCOMH 0xdb
> +
> +#define MAX_CONTRAST 255
> +
> +struct ssd130x_deviceinfo {
> + u32 default_vcomh;
> + u32 default_dclk_div;
> + u32 default_dclk_frq;
> + int need_pwm;
> + int need_chargepump;
> +};
> +
> +struct ssd130x_device {
> + struct drm_device drm;
> + struct drm_simple_display_pipe pipe;
> + struct drm_display_mode mode;
> + struct drm_connector connector;
> + struct i2c_client *client;
> +
> + const struct ssd130x_deviceinfo *device_info;
> +
> + unsigned area_color_enable : 1;
> + unsigned com_invdir : 1;
> + unsigned com_lrremap : 1;
> + unsigned com_seq : 1;
> + unsigned lookup_table_set : 1;
> + unsigned low_power : 1;
> + unsigned seg_remap : 1;
> + u32 com_offset;
> + u32 contrast;
> + u32 dclk_div;
> + u32 dclk_frq;
> + u32 height;
> + u8 lookup_table[4];
> + u32 page_offset;
> + u32 col_offset;
> + u32 prechargep1;
> + u32 prechargep2;
> +
> + struct backlight_device *bl_dev;
> + struct pwm_device *pwm;
> + struct gpio_desc *reset;
> + struct regulator *vbat_reg;
> + u32 vcomh;
> + u32 width;
> + /* Cached address ranges */
> + u8 col_start;
> + u8 col_end;
> + u8 page_start;
> + u8 page_end;
> +};
> +
> +struct ssd130x_array {
> + u8 type;
> + u8 data[];
> +};
> +
> +static inline struct ssd130x_device *drm_to_ssd130x(struct drm_device *drm)
> +{
> + return container_of(drm, struct ssd130x_device, drm);
> +}
> +
> +static struct ssd130x_array *ssd130x_alloc_array(u32 len, u8 type)
> +{
> + struct ssd130x_array *array;
> +
> + array = kzalloc(sizeof(struct ssd130x_array) + len, GFP_KERNEL);
> + if (!array)
> + return NULL;
> +
> + array->type = type;
> +
> + return array;
> +}
> +
> +static int ssd130x_write_array(struct i2c_client *client,
> + struct ssd130x_array *array, u32 len)
> +{
> + int ret;
> +
> + len += sizeof(struct ssd130x_array);
> +
> + ret = i2c_master_send(client, (u8 *)array, len);
> + if (ret != len) {
> + dev_err(&client->dev, "Couldn't send I2C command.\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static inline int ssd130x_write_cmd(struct i2c_client *client, u8 cmd)
> +{
> + struct ssd130x_array *array;
> + int ret;
> +
> + array = ssd130x_alloc_array(1, SSD130X_COMMAND);
> + if (!array)
> + return -ENOMEM;
> +
> + array->data[0] = cmd;
> +
> + ret = ssd130x_write_array(client, array, 1);
> + kfree(array);
> +
> + return ret;
> +}
> +
> +static int ssd130x_set_col_range(struct ssd130x_device *ssd130x,
> + u8 col_start, u8 cols)
> +{
> + u8 col_end = col_start + cols - 1;
> + int ret;
> +
> + if (col_start == ssd130x->col_start && col_end == ssd130x->col_end)
> + return 0;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_COL_RANGE);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, col_start);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, col_end);
> + if (ret < 0)
> + return ret;
> +
> + ssd130x->col_start = col_start;
> + ssd130x->col_end = col_end;
> + return 0;
> +}
> +
> +static int ssd130x_set_page_range(struct ssd130x_device *ssd130x,
> + u8 page_start, u8 pages)
> +{
> + u8 page_end = page_start + pages - 1;
> + int ret;
> +
> + if (page_start == ssd130x->page_start && page_end == ssd130x->page_end)
> + return 0;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_PAGE_RANGE);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, page_start);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, page_end);
> + if (ret < 0)
> + return ret;
> +
> + ssd130x->page_start = page_start;
> + ssd130x->page_end = page_end;
> + return 0;
> +}
> +
> +static int ssd130x_update_display(struct ssd130x_device *ssd130x, u8 *buf,
> + u32 width, u32 height)
> +{
> + struct ssd130x_array *array;
> + unsigned int line_length = DIV_ROUND_UP(width, 8);
> + unsigned int pages = DIV_ROUND_UP(height, 8);
> + u32 array_idx = 0;
> + int ret, i, j, k;
> +
> + array = ssd130x_alloc_array(width * pages, SSD130X_DATA);
> + if (!array)
> + return -ENOMEM;
> +
> + /*
> + * The screen is divided in pages, each having a height of 8
> + * pixels, and the width of the screen. When sending a byte of
> + * data to the controller, it gives the 8 bits for the current
> + * column. I.e, the first byte are the 8 bits of the first
> + * column, then the 8 bits for the second column, etc.
> + *
> + *
> + * Representation of the screen, assuming it is 5 bits
> + * wide. Each letter-number combination is a bit that controls
> + * one pixel.
> + *
> + * A0 A1 A2 A3 A4
> + * B0 B1 B2 B3 B4
> + * C0 C1 C2 C3 C4
> + * D0 D1 D2 D3 D4
> + * E0 E1 E2 E3 E4
> + * F0 F1 F2 F3 F4
> + * G0 G1 G2 G3 G4
> + * H0 H1 H2 H3 H4
> + *
> + * If you want to update this screen, you need to send 5 bytes:
> + * (1) A0 B0 C0 D0 E0 F0 G0 H0
> + * (2) A1 B1 C1 D1 E1 F1 G1 H1
> + * (3) A2 B2 C2 D2 E2 F2 G2 H2
> + * (4) A3 B3 C3 D3 E3 F3 G3 H3
> + * (5) A4 B4 C4 D4 E4 F4 G4 H4
> + */
> +
> + ret = ssd130x_set_col_range(ssd130x, ssd130x->col_offset, width);
> + if (ret < 0)
> + goto out_free;
> +
> + ret = ssd130x_set_page_range(ssd130x, ssd130x->page_offset / 8, pages);
> + if (ret < 0)
> + goto out_free;
> +
> + for (i = 0; i < pages; i++) {
> + int m = 8;
> +
> + /* Last page may be partial */
> + if (8 * (i + 1) > ssd130x->height)
> + m = ssd130x->height % 8;
> + for (j = 0; j < width; j++) {
> + u8 data = 0;
> +
> + for (k = 0; k < m; k++) {
> + u8 byte = buf[(8 * i + k) * line_length +
> + j / 8];
> + u8 bit = (byte >> (j % 8)) & 1;
> +
> + data |= bit << k;
> + }
> + array->data[array_idx++] = data;
> + }
> + }
> +
> + ret = ssd130x_write_array(ssd130x->client, array, width * pages);
> +
> +out_free:
> + kfree(array);
> + return ret;
> +}
> +
> +static void ssd130x_gray8_to_mono_reversed(u8 *buf, u32 width, u32 height)
> +{
> + u8 *gray8 = buf, *mono = buf;
> + int y, xb, i;
> +
> + for (y = 0; y < height; y++)
> + for (xb = 0; xb < width / 8; xb++) {
> + u8 byte = 0x00;
> +
> + for (i = 0; i < 8; i++) {
> + int x = xb * 8 + i;
> +
> + byte >>= 1;
> + if (gray8[y * width + x] >> 7)
> + byte |= BIT(7);
> + }
> + *mono++ = byte;
> + }
> +}
> +
> +static int ssd130x_fb_blit_rect(struct drm_framebuffer *fb, const struct dma_buf_map *map,
> + struct drm_rect *rect)
> +{
> + struct ssd130x_device *ssd130x = drm_to_ssd130x(fb->dev);
> + void *vmap = map->vaddr; /* TODO: Use mapping abstraction properly */
> + int idx, ret = 0;
> + u8 *buf = NULL;
> +
> + if (!drm_dev_enter(fb->dev, &idx))
> + return -ENODEV;
> +
> + buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
> + if (!buf) {
> + ret = -ENOMEM;
> + goto out_exit;
> + }
> +
> + drm_fb_xrgb8888_to_gray8(buf, 0, vmap, fb, rect);
> +
> + ssd130x_gray8_to_mono_reversed(buf, fb->width, fb->height);
> +
> + ssd130x_update_display(ssd130x, buf, fb->width, fb->height);
> +
> + kfree(buf);
> +out_exit:
> + drm_dev_exit(idx);
> +
> + return ret;
> +}
> +
> +static void ssd130x_display_pipe_enable(struct drm_simple_display_pipe *pipe,
> + struct drm_crtc_state *crtc_state,
> + struct drm_plane_state *plane_state)
> +{
> + struct ssd130x_device *ssd130x = drm_to_ssd130x(pipe->crtc.dev);
> + int idx;
> +
> + if (!drm_dev_enter(pipe->crtc.dev, &idx))
> + return;
> +
> + backlight_enable(ssd130x->bl_dev);
> +
> + ssd130x_write_cmd(ssd130x->client, SSD130X_DISPLAY_ON);
> +}
> +
> +static void ssd130x_display_pipe_disable(struct drm_simple_display_pipe *pipe)
> +{
> + struct ssd130x_device *ssd130x = drm_to_ssd130x(pipe->crtc.dev);
> +
> + ssd130x_write_cmd(ssd130x->client, SSD130X_DISPLAY_OFF);
> +
> + backlight_disable(ssd130x->bl_dev);
> +}
> +
> +static void ssd130x_display_pipe_update(struct drm_simple_display_pipe *pipe,
> + struct drm_plane_state *old_plane_state)
> +{
> + struct drm_plane_state *state = pipe->plane.state;
> + struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
> + struct drm_rect rect;
> +
> + if (!pipe->crtc.state->active)
> + return;
> +
> + if (drm_atomic_helper_damage_merged(old_plane_state, state, &rect))
> + ssd130x_fb_blit_rect(state->fb, &shadow_plane_state->data[0], &rect);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs ssd130x_pipe_funcs = {
> + .enable = ssd130x_display_pipe_enable,
> + .disable = ssd130x_display_pipe_disable,
> + .update = ssd130x_display_pipe_update,
> + DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
> +};
> +
> +static int ssd130x_connector_get_modes(struct drm_connector *connector)
> +{
> + struct ssd130x_device *ssd130x = drm_to_ssd130x(connector->dev);
> + struct drm_display_mode *mode;
> +
> + mode = drm_mode_duplicate(connector->dev, &ssd130x->mode);
> + if (!mode) {
> + DRM_ERROR("Failed to duplicate mode\n");
> + return 0;
> + }
> +
> + connector->display_info.width_mm = mode->width_mm;
> + connector->display_info.height_mm = mode->height_mm;
> + connector->display_info.bpc = 32;
> +
> + drm_mode_set_name(mode);
> + mode->type |= DRM_MODE_TYPE_PREFERRED;
> + drm_mode_probed_add(connector, mode);
> +
> + return 1;
> +}
> +
> +static const struct drm_connector_helper_funcs ssd130x_connector_helper_funcs = {
> + .get_modes = ssd130x_connector_get_modes,
> +};
> +
> +static const struct drm_connector_funcs ssd130x_connector_funcs = {
> + .reset = drm_atomic_helper_connector_reset,
> + .fill_modes = drm_helper_probe_single_connector_modes,
> + .destroy = drm_connector_cleanup,
> + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +};
> +
> +static const struct drm_mode_config_funcs ssd130x_mode_config_funcs = {
> + .fb_create = drm_gem_fb_create_with_dirty,
> + .atomic_check = drm_atomic_helper_check,
> + .atomic_commit = drm_atomic_helper_commit,
> +};
> +
> +static const uint32_t ssd130x_formats[] = {
> + DRM_FORMAT_XRGB8888,
> +};
> +
> +DEFINE_DRM_GEM_FOPS(ssd130x_fops);
> +
> +static const struct drm_driver ssd130x_drm_driver = {
> + DRM_GEM_SHMEM_DRIVER_OPS,
> + .name = DRIVER_NAME,
> + .desc = DRIVER_DESC,
> + .date = DRIVER_DATE,
> + .major = DRIVER_MAJOR,
> + .minor = DRIVER_MINOR,
> + .driver_features = DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
> + .fops = &ssd130x_fops,
> +};
> +
> +static int ssd130x_pwm_enable(struct ssd130x_device *ssd130x)
> +{
> + struct pwm_state pwmstate;
> +
> + ssd130x->pwm = pwm_get(&ssd130x->client->dev, NULL);
> + if (IS_ERR(ssd130x->pwm)) {
> + dev_err(&ssd130x->client->dev, "Could not get PWM from device tree!\n");
> + return PTR_ERR(ssd130x->pwm);
> + }
> +
> + pwm_init_state(ssd130x->pwm, &pwmstate);
> + pwm_set_relative_duty_cycle(&pwmstate, 50, 100);
> + pwm_apply_state(ssd130x->pwm, &pwmstate);
> +
> + /* Enable the PWM */
> + pwm_enable(ssd130x->pwm);
> +
> + dev_dbg(&ssd130x->client->dev, "Using PWM%d with a %lluns period.\n",
> + ssd130x->pwm->pwm, pwm_get_period(ssd130x->pwm));
> +
> + return 0;
> +}
> +
> +static int ssd130x_init(struct ssd130x_device *ssd130x)
> +{
> + u32 precharge, dclk, com_invdir, compins;
> + int ret;
> +
> + /* Set initial contrast */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_CONTRAST);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, ssd130x->contrast);
> + if (ret < 0)
> + return ret;
> +
> + /* Set segment re-map */
> + if (ssd130x->seg_remap) {
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SEG_REMAP_ON);
> + if (ret < 0)
> + return ret;
> + }
> +
> + /* Set COM direction */
> + com_invdir = 0xc0 | ssd130x->com_invdir << 3;
> + ret = ssd130x_write_cmd(ssd130x->client, com_invdir);
> + if (ret < 0)
> + return ret;
> +
> + /* Set multiplex ratio value */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_MULTIPLEX_RATIO);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, ssd130x->height - 1);
> + if (ret < 0)
> + return ret;
> +
> + /* set display offset value */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_DISPLAY_OFFSET);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, ssd130x->com_offset);
> + if (ret < 0)
> + return ret;
> +
> + /* Set clock frequency */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_CLOCK_FREQ);
> + if (ret < 0)
> + return ret;
> +
> + dclk = ((ssd130x->dclk_div - 1) & 0xf) | (ssd130x->dclk_frq & 0xf) << 4;
> + ret = ssd130x_write_cmd(ssd130x->client, dclk);
> + if (ret < 0)
> + return ret;
> +
> + /* Set Area Color Mode ON/OFF & Low Power Display Mode */
> + if (ssd130x->area_color_enable || ssd130x->low_power) {
> + u32 mode;
> +
> + ret = ssd130x_write_cmd(ssd130x->client,
> + SSD130X_SET_AREA_COLOR_MODE);
> + if (ret < 0)
> + return ret;
> +
> + mode = (ssd130x->area_color_enable ? 0x30 : 0) |
> + (ssd130x->low_power ? 5 : 0);
> + ret = ssd130x_write_cmd(ssd130x->client, mode);
> + if (ret < 0)
> + return ret;
> + }
> +
> + /* Set precharge period in number of ticks from the internal clock */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_PRECHARGE_PERIOD);
> + if (ret < 0)
> + return ret;
> +
> + precharge = (ssd130x->prechargep1 & 0xf) | (ssd130x->prechargep2 & 0xf) << 4;
> + ret = ssd130x_write_cmd(ssd130x->client, precharge);
> + if (ret < 0)
> + return ret;
> +
> + /* Set COM pins configuration */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_COM_PINS_CONFIG);
> + if (ret < 0)
> + return ret;
> +
> + compins = 0x02 | !ssd130x->com_seq << 4 | ssd130x->com_lrremap << 5;
> + ret = ssd130x_write_cmd(ssd130x->client, compins);
> + if (ret < 0)
> + return ret;
> +
> + /* Set VCOMH */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_VCOMH);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, ssd130x->vcomh);
> + if (ret < 0)
> + return ret;
> +
> + /* Turn on the DC-DC Charge Pump */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_CHARGE_PUMP);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client,
> + BIT(4) | (ssd130x->device_info->need_chargepump ? BIT(2) : 0));
> + if (ret < 0)
> + return ret;
> +
> + /* Set lookup table */
> + if (ssd130x->lookup_table_set) {
> + int i;
> +
> + ret = ssd130x_write_cmd(ssd130x->client,
> + SSD130X_SET_LOOKUP_TABLE);
> + if (ret < 0)
> + return ret;
> +
> + for (i = 0; i < ARRAY_SIZE(ssd130x->lookup_table); ++i) {
> + u8 val = ssd130x->lookup_table[i];
> +
> + if (val < 31 || val > 63)
> + dev_warn(&ssd130x->client->dev,
> + "lookup table index %d value out of range 31 <= %d <= 63\n",
> + i, val);
> + ret = ssd130x_write_cmd(ssd130x->client, val);
> + if (ret < 0)
> + return ret;
> + }
> + }
> +
> + /* Switch to horizontal addressing mode */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_SET_ADDRESS_MODE);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client,
> + SSD130X_SET_ADDRESS_MODE_HORIZONTAL);
> + if (ret < 0)
> + return ret;
> +
> + /* Turn on the display */
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_DISPLAY_ON);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int ssd130x_update_bl(struct backlight_device *bdev)
> +{
> + struct ssd130x_device *ssd130x = bl_get_data(bdev);
> + int brightness = bdev->props.brightness;
> + int ret;
> +
> + ssd130x->contrast = brightness;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, SSD130X_CONTRAST);
> + if (ret < 0)
> + return ret;
> +
> + ret = ssd130x_write_cmd(ssd130x->client, ssd130x->contrast);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int ssd130x_get_brightness(struct backlight_device *bdev)
> +{
> + struct ssd130x_device *ssd130x = bl_get_data(bdev);
> +
> + return ssd130x->contrast;
> +}
> +
> +static const struct backlight_ops ssd130xfb_bl_ops = {
> + .update_status = ssd130x_update_bl,
> + .get_brightness = ssd130x_get_brightness,
> +};
> +
> +static void ssd130x_reset(struct ssd130x_device *ssd130x)
> +{
> + /* Reset the screen */
> + gpiod_set_value_cansleep(ssd130x->reset, 1);
> + udelay(4);
> + gpiod_set_value_cansleep(ssd130x->reset, 0);
> + udelay(4);
> +}
> +
> +static void ssd130x_parse_properties(struct ssd130x_device *ssd130x)
> +{
> + struct device *dev = &ssd130x->client->dev;
> +
> + if (device_property_read_u32(dev, "solomon,width", &ssd130x->width))
> + ssd130x->width = 96;
> +
> + if (device_property_read_u32(dev, "solomon,height", &ssd130x->height))
> + ssd130x->height = 16;
> +
> + if (device_property_read_u32(dev, "solomon,page-offset", &ssd130x->page_offset))
> + ssd130x->page_offset = 1;
> +
> + if (device_property_read_u32(dev, "solomon,col-offset", &ssd130x->col_offset))
> + ssd130x->col_offset = 0;
> +
> + if (device_property_read_u32(dev, "solomon,com-offset", &ssd130x->com_offset))
> + ssd130x->com_offset = 0;
> +
> + if (device_property_read_u32(dev, "solomon,prechargep1", &ssd130x->prechargep1))
> + ssd130x->prechargep1 = 2;
> +
> + if (device_property_read_u32(dev, "solomon,prechargep2", &ssd130x->prechargep2))
> + ssd130x->prechargep2 = 2;
> +
> + if (!device_property_read_u8_array(dev, "solomon,lookup-table",
> + ssd130x->lookup_table,
> + ARRAY_SIZE(ssd130x->lookup_table)))
> + ssd130x->lookup_table_set = 1;
> +
> + ssd130x->seg_remap = !device_property_read_bool(dev, "solomon,segment-no-remap");
> + ssd130x->com_seq = device_property_read_bool(dev, "solomon,com-seq");
> + ssd130x->com_lrremap = device_property_read_bool(dev, "solomon,com-lrremap");
> + ssd130x->com_invdir = device_property_read_bool(dev, "solomon,com-invdir");
> + ssd130x->area_color_enable =
> + device_property_read_bool(dev, "solomon,area-color-enable");
> + ssd130x->low_power = device_property_read_bool(dev, "solomon,low-power");
> +
> + ssd130x->contrast = 127;
> + ssd130x->vcomh = ssd130x->device_info->default_vcomh;
> +
> + /* Setup display timing */
> + if (device_property_read_u32(dev, "solomon,dclk-div", &ssd130x->dclk_div))
> + ssd130x->dclk_div = ssd130x->device_info->default_dclk_div;
> + if (device_property_read_u32(dev, "solomon,dclk-frq", &ssd130x->dclk_frq))
> + ssd130x->dclk_frq = ssd130x->device_info->default_dclk_frq;
> +}
> +
> +static void ssd130x_set_mode(struct ssd130x_device *ssd130x)
> +{
> + struct drm_display_mode *mode = &ssd130x->mode;
> + struct drm_device *drm = &ssd130x->drm;
> +
> + mode->type = DRM_MODE_TYPE_DRIVER;
> + mode->clock = 1;
> + mode->hdisplay = mode->htotal = ssd130x->width;
> + mode->hsync_start = mode->hsync_end = ssd130x->width;
> + mode->vdisplay = mode->vtotal = ssd130x->height;
> + mode->vsync_start = mode->vsync_end = ssd130x->height;
> + mode->width_mm = 27;
> + mode->height_mm = 27;
> +
> + drm->mode_config.min_width = ssd130x->width;
> + drm->mode_config.max_width = ssd130x->width;
> + drm->mode_config.min_height = ssd130x->height;
> + drm->mode_config.max_height = ssd130x->height;
> + drm->mode_config.preferred_depth = 32;
> + drm->mode_config.funcs = &ssd130x_mode_config_funcs;
> +}
> +
> +static int ssd130x_probe(struct i2c_client *client)
> +{
> + struct device *dev = &client->dev;
> + struct ssd130x_device *ssd130x;
> + struct backlight_device *bl;
> + struct drm_device *drm;
> + char bl_name[12];
> + int ret;
> +
> + ssd130x = devm_drm_dev_alloc(dev, &ssd130x_drm_driver,
> + struct ssd130x_device, drm);
> + if (IS_ERR(ssd130x))
> + return PTR_ERR(ssd130x);
> +
> + drm = &ssd130x->drm;
> +
> + ret = drmm_mode_config_init(drm);
> + if (ret)
> + return ret;
> +
> + ssd130x->client = client;
> +
> + ssd130x->device_info = device_get_match_data(dev);
> +
> + ssd130x_parse_properties(ssd130x);
> +
> + ssd130x_set_mode(ssd130x);
> +
> + ssd130x->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> + if (IS_ERR(ssd130x->reset)) {
> + dev_err(dev, "failed to get reset gpio: %ld\n",
> + PTR_ERR(ssd130x->reset));
> + return PTR_ERR(ssd130x->reset);
> + }
> +
> + ssd130x->vbat_reg = devm_regulator_get_optional(dev, "vbat");
> + if (IS_ERR(ssd130x->vbat_reg)) {
> + ret = PTR_ERR(ssd130x->vbat_reg);
> + if (ret == -ENODEV) {
> + ssd130x->vbat_reg = NULL;
> + } else {
> + dev_err(dev, "failed to get VBAT regulator: %d\n", ret);
> + return ret;
> + }
> + }
> +
> + drm_connector_helper_add(&ssd130x->connector, &ssd130x_connector_helper_funcs);
> + ret = drm_connector_init(drm, &ssd130x->connector, &ssd130x_connector_funcs,
> + DRM_MODE_CONNECTOR_Unknown);
> + if (ret)
> + return ret;
> +
> + i2c_set_clientdata(client, ssd130x);
> +
> + if (ssd130x->reset)
> + ssd130x_reset(ssd130x);
> +
> + if (ssd130x->vbat_reg) {
> + ret = regulator_enable(ssd130x->vbat_reg);
> + if (ret) {
> + dev_err(dev, "failed to enable VBAT: %d\n", ret);
> + return ret;
> + }
> + }
> +
> + ret = ssd130x_init(ssd130x);
> + if (ret)
> + goto regulator_disable;
> +
> + if (ssd130x->device_info->need_pwm) {
> + ret = ssd130x_pwm_enable(ssd130x);
> + if (ret)
> + goto regulator_disable;
> + }
> +
> + snprintf(bl_name, sizeof(bl_name), "ssd130x%d", drm->primary->index);
> + bl = backlight_device_register(bl_name, dev, ssd130x, &ssd130xfb_bl_ops,
> + NULL);
> + if (IS_ERR(bl)) {
> + ret = PTR_ERR(bl);
> + dev_err(dev, "unable to register backlight device: %d\n", ret);
> + goto pwm_disable;
> + }
> +
> + bl->props.brightness = ssd130x->contrast;
> + bl->props.max_brightness = MAX_CONTRAST;
> + ssd130x->bl_dev = bl;
> +
> + ret = drm_simple_display_pipe_init(drm, &ssd130x->pipe, &ssd130x_pipe_funcs,
> + ssd130x_formats, ARRAY_SIZE(ssd130x_formats),
> + NULL, &ssd130x->connector);
> + if (ret)
> + goto pwm_disable;
> +
> + drm_plane_enable_fb_damage_clips(&ssd130x->pipe.plane);
> +
> + drm_mode_config_reset(drm);
> +
> + ret = drm_dev_register(drm, 0);
> + if (ret)
> + goto backlight_unregister;
> +
> + drm_fbdev_generic_setup(drm, 0);
> +
> + return 0;
> +
> +backlight_unregister:
> + backlight_device_unregister(ssd130x->bl_dev);
> +pwm_disable:
> + if (ssd130x->device_info->need_pwm) {
> + pwm_disable(ssd130x->pwm);
> + pwm_put(ssd130x->pwm);
> + }
> +regulator_disable:
> + if (ssd130x->vbat_reg)
> + regulator_disable(ssd130x->vbat_reg);
> + return ret;
> +}
> +
> +static int ssd130x_remove(struct i2c_client *client)
> +{
> + struct ssd130x_device *ssd130x = i2c_get_clientdata(client);
> +
> + drm_dev_unplug(&ssd130x->drm);
> +
> + ssd130x_write_cmd(ssd130x->client, SSD130X_DISPLAY_OFF);
> +
> + backlight_device_unregister(ssd130x->bl_dev);
> +
> + if (ssd130x->device_info->need_pwm) {
> + pwm_disable(ssd130x->pwm);
> + pwm_put(ssd130x->pwm);
> + }
> + if (ssd130x->vbat_reg)
> + regulator_disable(ssd130x->vbat_reg);
> +
> + return 0;
> +}
> +
> +static void ssd130x_shutdown(struct i2c_client *client)
> +{
> + struct ssd130x_device *ssd130x = i2c_get_clientdata(client);
> +
> + drm_atomic_helper_shutdown(&ssd130x->drm);
> +}
> +
> +static struct ssd130x_deviceinfo ssd130x_ssd1305_deviceinfo = {
> + .default_vcomh = 0x34,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 7,
> +};
> +
> +static struct ssd130x_deviceinfo ssd130x_ssd1306_deviceinfo = {
> + .default_vcomh = 0x20,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 8,
> + .need_chargepump = 1,
> +};
> +
> +static struct ssd130x_deviceinfo ssd130x_ssd1307_deviceinfo = {
> + .default_vcomh = 0x20,
> + .default_dclk_div = 2,
> + .default_dclk_frq = 12,
> + .need_pwm = 1,
> +};
> +
> +static struct ssd130x_deviceinfo ssd130x_ssd1309_deviceinfo = {
> + .default_vcomh = 0x34,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 10,
> +};
> +
> +static const struct of_device_id ssd130x_of_match[] = {
> + {
> + .compatible = "solomon,ssd1305fb-i2c",
> + .data = (void *)&ssd130x_ssd1305_deviceinfo,
> + },
> + {
> + .compatible = "solomon,ssd1306fb-i2c",
> + .data = (void *)&ssd130x_ssd1306_deviceinfo,
> + },
> + {
> + .compatible = "solomon,ssd1307fb-i2c",
> + .data = (void *)&ssd130x_ssd1307_deviceinfo,
> + },
> + {
> + .compatible = "solomon,ssd1309fb-i2c",
> + .data = (void *)&ssd130x_ssd1309_deviceinfo,
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, ssd130x_of_match);
> +
> +
> +static struct i2c_driver ssd130x_i2c_driver = {
> + .driver = {
> + .name = DRIVER_NAME,
> + .of_match_table = ssd130x_of_match,
> + },
> + .probe_new = ssd130x_probe,
> + .remove = ssd130x_remove,
> + .shutdown = ssd130x_shutdown,
> +};
> +
> +module_i2c_driver(ssd130x_i2c_driver);
> +
> +MODULE_DESCRIPTION(DRIVER_DESC);
> +MODULE_AUTHOR("Javier Martinez Canillas <javierm@redhat.com>");
> +MODULE_LICENSE("GPL v2");
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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