Re: [PATCH v3 2/2] drm/panel: Add driver for Samsung S6E63M0 panel

Andrzej Hajda
2019-02-11T15:35:29Z

On 02.02.2019 15:27, Paweł Chmiel wrote:
> This patch adds Samsung S6E63M0 AMOLED LCD panel driver, connected over
> spi. It's based on already removed, non dt s6e63m0 driver and
> panel-samsung-ld9040. It can be found for example in some of Samsung
> Aries based phones.
>
> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> ---
> Changes from v2:
> - VIDEOMODE_HELPERS is not needed in Kconfig
> - Added help text to Kconfig
> - Remove unneeded videomode includes/fields
> - Add sentinel comment in s6e63m0_of_match struct
> - Handle errors during registration of backlight device. We shouldn't
> register panel if we fail to register backlight device
> - Added Reviewed-by
>
> Changes from v1:
> - Correct order of Kconfig/Makefile entry
> - Fix SPDX tag, so it matches value of MODULE_LICENSE
> - Remove inclusion of drmP.h
> - Fix code formatting
> - Use DRM_DEV_ERROR/DEBUG
> - Extract hardcoded values
> - Remove possibility to change gamma through sysfs, leaving only one
> gamma table values
> - Fix reset_gpio handling, so it'll be asserted in power_on and
> deasserted in power_off. Also do it before turning voltage on.
> - Disable backlight and enter sleep mode in disable callback.
> Previously it was done in unprepare
> - Enable display and backlight in enable callback. Previously it was
> done in prepare
> - Hardcode display timings and delays. Previously they were readed
> from device tree
> - We're using SPDX, so we don't need to have license body
> - Use MIPI_DCS_EXIT_SLEEP_MODE and MIPI_DCS_SET_DISPLAY_ON
> - Rename MAX_GAMMA_LEVEL to NUM_GAMMA_LEVELS
> - Ommit get_brightness callback
> - Use backlight_enable/disable API, like it's done in other panel
> drivers (for example panel-simple)
> - Make set_brightness called only from backlight api, like it's done
> in other panel drivers (for example panel-simple).
> - Reset gpio should be set to GPIOD_OUT_HIGH. It's declared as active
> low in device tree
> - Don't call power_off in remove callback
> ---
> drivers/gpu/drm/panel/Kconfig | 9 +
> drivers/gpu/drm/panel/Makefile | 1 +
> drivers/gpu/drm/panel/panel-samsung-s6e63m0.c | 517 ++++++++++++++++++
> 3 files changed, 527 insertions(+)
> create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e63m0.c
>
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 3f3537719beb..45e9ab4b7857 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -158,6 +158,15 @@ config DRM_PANEL_SAMSUNG_S6E63J0X03
> depends on BACKLIGHT_CLASS_DEVICE
> select VIDEOMODE_HELPERS
>
> +config DRM_PANEL_SAMSUNG_S6E63M0
> + tristate "Samsung S6E63M0 RGB/SPI panel"
> + depends on OF
> + depends on SPI
> + depends on BACKLIGHT_CLASS_DEVICE
> + help
> + Say Y here if you want to enable support for Samsung s6e63m0
> + AMOLED LCD panel.
> +
> config DRM_PANEL_SAMSUNG_S6E8AA0
> tristate "Samsung S6E8AA0 DSI video mode panel"
> depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 4396658a7996..4507a2d253ac 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o
> obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6D16D0) += panel-samsung-s6d16d0.o
> obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E3HA2) += panel-samsung-s6e3ha2.o
> obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o
> +obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0) += panel-samsung-s6e63m0.o
> obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
> obj-$(CONFIG_DRM_PANEL_SEIKO_43WVF1G) += panel-seiko-43wvf1g.o
> obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o
> diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c b/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c
> new file mode 100644
> index 000000000000..4312aa3e4386
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c
> @@ -0,0 +1,517 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * S6E63M0 AMOLED LCD drm_panel driver.
> + *
> + * Copyright (C) 2019 Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
> + * Derived from drivers/gpu/drm/panel-samsung-ld9040.c
> + *
> + * Andrzej Hajda <a.hajda@samsung.com>
> + */
> +
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#include <video/mipi_display.h>
> +
> +/* Manufacturer Command Set */
> +#define MCS_ELVSS_ON 0xb1
> +#define MCS_ACL_CTRL 0xc0
> +#define MCS_DISPLAY_CONDITION 0xf2
> +#define MCS_ETC_CONDITION 0xf6
> +#define MCS_PANEL_CONDITION 0xF8
> +#define MCS_GAMMA_CTRL 0xfa
> +
> +#define NUM_GAMMA_LEVELS 11
> +#define GAMMA_TABLE_COUNT 23
> +
> +#define DATA_MASK 0x100
> +
> +#define MAX_BRIGHTNESS (NUM_GAMMA_LEVELS - 1)
> +
> +/* array of gamma tables for gamma value 2.2 */
> +static u8 const s6e63m0_gamma_22[NUM_GAMMA_LEVELS][GAMMA_TABLE_COUNT] = {
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x78, 0xEC, 0x3D, 0xC8,
> + 0xC2, 0xB6, 0xC4, 0xC7, 0xB6, 0xD5, 0xD7,
> + 0xCC, 0x00, 0x39, 0x00, 0x36, 0x00, 0x51 },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x73, 0x4A, 0x3D, 0xC0,
> + 0xC2, 0xB1, 0xBB, 0xBE, 0xAC, 0xCE, 0xCF,
> + 0xC5, 0x00, 0x5D, 0x00, 0x5E, 0x00, 0x82 },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x70, 0x51, 0x3E, 0xBF,
> + 0xC1, 0xAF, 0xB9, 0xBC, 0xAB, 0xCC, 0xCC,
> + 0xC2, 0x00, 0x65, 0x00, 0x67, 0x00, 0x8D },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x6C, 0x54, 0x3A, 0xBC,
> + 0xBF, 0xAC, 0xB7, 0xBB, 0xA9, 0xC9, 0xC9,
> + 0xBE, 0x00, 0x71, 0x00, 0x73, 0x00, 0x9E },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x69, 0x54, 0x37, 0xBB,
> + 0xBE, 0xAC, 0xB4, 0xB7, 0xA6, 0xC7, 0xC8,
> + 0xBC, 0x00, 0x7B, 0x00, 0x7E, 0x00, 0xAB },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x66, 0x55, 0x34, 0xBA,
> + 0xBD, 0xAB, 0xB1, 0xB5, 0xA3, 0xC5, 0xC6,
> + 0xB9, 0x00, 0x85, 0x00, 0x88, 0x00, 0xBA },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x63, 0x53, 0x31, 0xB8,
> + 0xBC, 0xA9, 0xB0, 0xB5, 0xA2, 0xC4, 0xC4,
> + 0xB8, 0x00, 0x8B, 0x00, 0x8E, 0x00, 0xC2 },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x62, 0x54, 0x30, 0xB9,
> + 0xBB, 0xA9, 0xB0, 0xB3, 0xA1, 0xC1, 0xC3,
> + 0xB7, 0x00, 0x91, 0x00, 0x95, 0x00, 0xDA },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x66, 0x58, 0x34, 0xB6,
> + 0xBA, 0xA7, 0xAF, 0xB3, 0xA0, 0xC1, 0xC2,
> + 0xB7, 0x00, 0x97, 0x00, 0x9A, 0x00, 0xD1 },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x64, 0x56, 0x33, 0xB6,
> + 0xBA, 0xA8, 0xAC, 0xB1, 0x9D, 0xC1, 0xC1,
> + 0xB7, 0x00, 0x9C, 0x00, 0x9F, 0x00, 0xD6 },
> + { MCS_GAMMA_CTRL, 0x00,
> + 0x18, 0x08, 0x24, 0x5f, 0x50, 0x2d, 0xB6,
> + 0xB9, 0xA7, 0xAd, 0xB1, 0x9f, 0xbe, 0xC0,
> + 0xB5, 0x00, 0xa0, 0x00, 0xa4, 0x00, 0xdb },
> +};
> +
> +struct s6e63m0 {
> + struct device *dev;
> + struct drm_panel panel;
> + struct backlight_device *bl_dev;
> +
> + struct regulator_bulk_data supplies[2];
> + struct gpio_desc *reset_gpio;
> +
> + bool prepared;
> + bool enabled;
> +
> + /*
> + * This field is tested by functions directly accessing bus before
> + * transfer, transfer is skipped if it is set. In case of transfer
> + * failure or unexpected response the field is set to error value.
> + * Such construct allows to eliminate many checks in higher level
> + * functions.
> + */
> + int error;
> +};
> +
> +static const struct drm_display_mode default_mode = {
> + .clock = 25628,
> + .hdisplay = 480,
> + .hsync_start = 480 + 16,
> + .hsync_end = 480 + 16 + 2,
> + .htotal = 480 + 16 + 2 + 16,
> + .vdisplay = 800,
> + .vsync_start = 800 + 28,
> + .vsync_end = 800 + 28 + 2,
> + .vtotal = 800 + 28 + 2 + 1,
> + .vrefresh = 60,
> + .width_mm = 53,
> + .height_mm = 89,
> + .flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
> +};
> +
> +static inline struct s6e63m0 *panel_to_s6e63m0(struct drm_panel *panel)
> +{
> + return container_of(panel, struct s6e63m0, panel);
> +}
> +
> +static int s6e63m0_clear_error(struct s6e63m0 *ctx)
> +{
> + int ret = ctx->error;
> +
> + ctx->error = 0;
> + return ret;
> +}
> +
> +static int s6e63m0_spi_write_word(struct s6e63m0 *ctx, u16 data)
> +{
> + struct spi_device *spi = to_spi_device(ctx->dev);
> + struct spi_transfer xfer = {
> + .len = 2,
> + .tx_buf = &data,
> + };
> + struct spi_message msg;
> +
> + spi_message_init(&msg);
> + spi_message_add_tail(&xfer, &msg);
> +
> + return spi_sync(spi, &msg);
> +}
> +
> +static void s6e63m0_dcs_write(struct s6e63m0 *ctx, const u8 *data, size_t len)
> +{
> + int ret = 0;
> +
> + if (ctx->error < 0 || len == 0)
> + return;
> +
> + DRM_DEV_DEBUG(ctx->dev, "writing dcs seq: %*ph\n", (int)len, data);
> + ret = s6e63m0_spi_write_word(ctx, *data);
> +
> + while (!ret && --len) {
> + ++data;
> + ret = s6e63m0_spi_write_word(ctx, *data | DATA_MASK);
> + }
> +
> + if (ret) {
> + DRM_DEV_ERROR(ctx->dev, "error %d writing dcs seq: %*ph\n", ret,
> + (int)len, data);
> + ctx->error = ret;
> + }
> +
> + usleep_range(300, 310);
> +}
> +
> +#define s6e63m0_dcs_write_seq_static(ctx, seq ...) \
> + ({ \
> + static const u8 d[] = { seq }; \
> + s6e63m0_dcs_write(ctx, d, ARRAY_SIZE(d)); \
> + })
> +
> +static void s6e63m0_brightness_set(struct s6e63m0 *ctx)
> +{
> + int brightness = ctx->bl_dev->props.brightness;
> +
> + /* disable and set new gamma */
> + s6e63m0_dcs_write(ctx, s6e63m0_gamma_22[brightness],
> + ARRAY_SIZE(s6e63m0_gamma_22[brightness]));
> +
> + /* update gamma table. */
> + s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_CTRL, 0x01);
> +}

I guess you can squash this callback into s6e63m0_set_brightness.
Moreover you performs transfer here unconditionally, regardless of panel
power state, it will fail when drm device is disabled (using echo 255
>/sys/class/backlight/...) - panel is also disabled - making transfer to
disabled panel by panel driver looks odd, moreover it could be little
bit racy. But in practice it could work.

Moreover I do not see usage of backlight_properties.power,
backlight_properties.state, but I do not understand how exactly
backlight interface should work, if someone can point out to proper
docs/usage of backlight API I will be glad.

> +
> +static void s6e63m0_init(struct s6e63m0 *ctx)
> +{
> + s6e63m0_dcs_write_seq_static(ctx, MCS_PANEL_CONDITION,
> + 0x01, 0x27, 0x27, 0x07, 0x07, 0x54, 0x9f,
> + 0x63, 0x86, 0x1a, 0x33, 0x0d, 0x00, 0x00);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MCS_DISPLAY_CONDITION,
> + 0x02, 0x03, 0x1c, 0x10, 0x10);
> + s6e63m0_dcs_write_seq_static(ctx, 0xf7,
> + 0x03, 0x00, 0x00);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_CTRL,
> + 0x00, 0x18, 0x08, 0x24, 0x64, 0x56, 0x33,
> + 0xb6, 0xba, 0xa8, 0xac, 0xb1, 0x9d, 0xc1,
> + 0xc1, 0xb7, 0x00, 0x9c, 0x00, 0x9f, 0x00,
> + 0xd6);
> + s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_CTRL,
> + 0x01);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MCS_ETC_CONDITION,
> + 0x00, 0x8c, 0x07);
> + s6e63m0_dcs_write_seq_static(ctx, 0xb3,
> + 0xc);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xb5,
> + 0x2c, 0x12, 0x0c, 0x0a, 0x10, 0x0e, 0x17,
> + 0x13, 0x1f, 0x1a, 0x2a, 0x24, 0x1f, 0x1b,
> + 0x1a, 0x17, 0x2b, 0x26, 0x22, 0x20, 0x3a,
> + 0x34, 0x30, 0x2c, 0x29, 0x26, 0x25, 0x23,
> + 0x21, 0x20, 0x1e, 0x1e);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xb6,
> + 0x00, 0x00, 0x11, 0x22, 0x33, 0x44, 0x44,
> + 0x44, 0x55, 0x55, 0x66, 0x66, 0x66, 0x66,
> + 0x66, 0x66);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xb7,
> + 0x2c, 0x12, 0x0c, 0x0a, 0x10, 0x0e, 0x17,
> + 0x13, 0x1f, 0x1a, 0x2a, 0x24, 0x1f, 0x1b,
> + 0x1a, 0x17, 0x2b, 0x26, 0x22, 0x20, 0x3a,
> + 0x34, 0x30, 0x2c, 0x29, 0x26, 0x25, 0x23,
> + 0x21, 0x20, 0x1e, 0x1e, 0x00, 0x00, 0x11,
> + 0x22, 0x33, 0x44, 0x44, 0x44, 0x55, 0x55,
> + 0x66, 0x66, 0x66, 0x66, 0x66, 0x66);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xb9,
> + 0x2c, 0x12, 0x0c, 0x0a, 0x10, 0x0e, 0x17,
> + 0x13, 0x1f, 0x1a, 0x2a, 0x24, 0x1f, 0x1b,
> + 0x1a, 0x17, 0x2b, 0x26, 0x22, 0x20, 0x3a,
> + 0x34, 0x30, 0x2c, 0x29, 0x26, 0x25, 0x23,
> + 0x21, 0x20, 0x1e, 0x1e);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xba,
> + 0x00, 0x00, 0x11, 0x22, 0x33, 0x44, 0x44,
> + 0x44, 0x55, 0x55, 0x66, 0x66, 0x66, 0x66,
> + 0x66, 0x66);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xc1,
> + 0x4d, 0x96, 0x1d, 0x00, 0x00, 0x01, 0xdf,
> + 0x00, 0x00, 0x03, 0x1f, 0x00, 0x00, 0x00,
> + 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x06,
> + 0x09, 0x0d, 0x0f, 0x12, 0x15, 0x18);
> +
> + s6e63m0_dcs_write_seq_static(ctx, 0xb2,
> + 0x10, 0x10, 0x0b, 0x05);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MCS_ACL_CTRL,
> + 0x01);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MCS_ELVSS_ON,
> + 0x0b);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MIPI_DCS_EXIT_SLEEP_MODE);
> +}
> +
> +static int s6e63m0_power_on(struct s6e63m0 *ctx)
> +{
> + int ret;
> +
> + gpiod_set_value(ctx->reset_gpio, 0);
> + msleep(120);
> +
> + ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> + if (ret < 0)
> + return ret;

Are you sure gpios before regulators, from my experience usually it is
reverse.

> +
> + msleep(25);
> +
> + return 0;
> +}
> +
> +static int s6e63m0_power_off(struct s6e63m0 *ctx)
> +{
> + int ret;
> +
> + ret = regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> + if (ret < 0)
> + return ret;
> +
> + gpiod_set_value(ctx->reset_gpio, 1);

Ditto.

> + msleep(120);

What is the point of this msleep?

I guess, the answer for above comments can be difficult, since datasheet
is not available, so if you just followed vendor code please feel free
to add:

Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>

--

Regards
Andrzej

> +
> + return 0;
> +}
> +
> +static int s6e63m0_disable(struct drm_panel *panel)
> +{
> + struct s6e63m0 *ctx = panel_to_s6e63m0(panel);
> +
> + if (!ctx->enabled)
> + return 0;
> +
> + backlight_disable(ctx->bl_dev);
> +
> + s6e63m0_dcs_write_seq_static(ctx, MIPI_DCS_ENTER_SLEEP_MODE);
> + msleep(200);
> +
> + ctx->enabled = false;
> +
> + return 0;
> +}
> +
> +static int s6e63m0_unprepare(struct drm_panel *panel)
> +{
> + struct s6e63m0 *ctx = panel_to_s6e63m0(panel);
> + int ret;
> +
> + if (!ctx->prepared)
> + return 0;
> +
> + s6e63m0_clear_error(ctx);
> +
> + ret = s6e63m0_power_off(ctx);
> + if (ret < 0)
> + return ret;
> +
> + ctx->prepared = false;
> +
> + return 0;
> +}
> +
> +static int s6e63m0_prepare(struct drm_panel *panel)
> +{
> + struct s6e63m0 *ctx = panel_to_s6e63m0(panel);
> + int ret;
> +
> + if (ctx->prepared)
> + return 0;
> +
> + ret = s6e63m0_power_on(ctx);
> + if (ret < 0)
> + return ret;
> +
> + s6e63m0_init(ctx);
> +
> + ret = s6e63m0_clear_error(ctx);
> +
> + if (ret < 0)
> + s6e63m0_unprepare(panel);
> +
> + ctx->prepared = true;
> +
> + return ret;
> +}
> +
> +static int s6e63m0_enable(struct drm_panel *panel)
> +{
> + struct s6e63m0 *ctx = panel_to_s6e63m0(panel);
> +
> + if (ctx->enabled)
> + return 0;
> +
> + s6e63m0_dcs_write_seq_static(ctx, MIPI_DCS_SET_DISPLAY_ON);
> +
> + backlight_enable(ctx->bl_dev);
> +
> + ctx->enabled = true;
> +
> + return 0;
> +}
> +
> +static int s6e63m0_get_modes(struct drm_panel *panel)
> +{
> + struct drm_connector *connector = panel->connector;
> + struct drm_display_mode *mode;
> +
> + mode = drm_mode_duplicate(panel->drm, &default_mode);
> + if (!mode) {
> + DRM_ERROR("failed to add mode %ux%ux@%u\n",
> + default_mode.hdisplay, default_mode.vdisplay,
> + default_mode.vrefresh);
> + return -ENOMEM;
> + }
> +
> + drm_mode_set_name(mode);
> +
> + mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> + drm_mode_probed_add(connector, mode);
> +
> + return 1;
> +}
> +
> +static const struct drm_panel_funcs s6e63m0_drm_funcs = {
> + .disable = s6e63m0_disable,
> + .unprepare = s6e63m0_unprepare,
> + .prepare = s6e63m0_prepare,
> + .enable = s6e63m0_enable,
> + .get_modes = s6e63m0_get_modes,
> +};
> +
> +static int s6e63m0_set_brightness(struct backlight_device *bd)
> +{
> + struct s6e63m0 *ctx = bl_get_data(bd);
> +
> + s6e63m0_brightness_set(ctx);
> +
> + return s6e63m0_clear_error(ctx);
> +}
> +
> +static const struct backlight_ops s6e63m0_backlight_ops = {
> + .update_status = s6e63m0_set_brightness,
> +};
> +
> +static int s6e63m0_backlight_register(struct s6e63m0 *ctx)
> +{
> + struct backlight_properties props = {
> + .type = BACKLIGHT_RAW,
> + .brightness = MAX_BRIGHTNESS,
> + .max_brightness = MAX_BRIGHTNESS
> + };
> + struct device *dev = ctx->dev;
> + int ret = 0;
> +
> + ctx->bl_dev = devm_backlight_device_register(dev, "panel", dev, ctx,
> + &s6e63m0_backlight_ops,
> + &props);
> + if (IS_ERR(ctx->bl_dev)) {
> + ret = PTR_ERR(ctx->bl_dev);
> + DRM_DEV_ERROR(dev, "error registering backlight device (%d)\n",
> + ret);
> + }
> +
> + return ret;
> +}
> +
> +static int s6e63m0_probe(struct spi_device *spi)
> +{
> + struct device *dev = &spi->dev;
> + struct s6e63m0 *ctx;
> + int ret;
> +
> + ctx = devm_kzalloc(dev, sizeof(struct s6e63m0), GFP_KERNEL);
> + if (!ctx)
> + return -ENOMEM;
> +
> + spi_set_drvdata(spi, ctx);
> +
> + ctx->dev = dev;
> + ctx->enabled = false;
> + ctx->prepared = false;
> +
> + ctx->supplies[0].supply = "vdd3";
> + ctx->supplies[1].supply = "vci";
> + ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ctx->supplies),
> + ctx->supplies);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "failed to get regulators: %d\n", ret);
> + return ret;
> + }
> +
> + ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(ctx->reset_gpio)) {
> + DRM_DEV_ERROR(dev, "cannot get reset-gpios %ld\n",
> + PTR_ERR(ctx->reset_gpio));
> + return PTR_ERR(ctx->reset_gpio);
> + }
> +
> + spi->bits_per_word = 9;
> + spi->mode = SPI_MODE_3;
> + ret = spi_setup(spi);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "spi setup failed.\n");
> + return ret;
> + }
> +
> + drm_panel_init(&ctx->panel);
> + ctx->panel.dev = dev;
> + ctx->panel.funcs = &s6e63m0_drm_funcs;
> +
> + ret = s6e63m0_backlight_register(ctx);
> + if (ret < 0)
> + return ret;
> +
> + return drm_panel_add(&ctx->panel);
> +}
> +
> +static int s6e63m0_remove(struct spi_device *spi)
> +{
> + struct s6e63m0 *ctx = spi_get_drvdata(spi);
> +
> + drm_panel_remove(&ctx->panel);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id s6e63m0_of_match[] = {
> + { .compatible = "samsung,s6e63m0" },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, s6e63m0_of_match);
> +
> +static struct spi_driver s6e63m0_driver = {
> + .probe = s6e63m0_probe,
> + .remove = s6e63m0_remove,
> + .driver = {
> + .name = "panel-samsung-s6e63m0",
> + .of_match_table = s6e63m0_of_match,
> + },
> +};
> +module_spi_driver(s6e63m0_driver);
> +
> +MODULE_AUTHOR("Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>");
> +MODULE_DESCRIPTION("s6e63m0 LCD Driver");
> +MODULE_LICENSE("GPL v2");