Re: [PATCH 2/2] drm/panel: Add a driver for Samsung s6e88a0-ams452ef01 panel

[Sam Ravnborg <sam@ravnborg.org>]

Hi Michael.

Thanks for submitting this driver.

The main feedback is that there is changes in the code,
and you need to base it on top of drm-misc-next.

The rest are small nits.

	Sam

On Sun, Jan 26, 2020 at 07:39:11PM +0100, michael.srba@seznam.cz wrote:
> From: Michael Srba <Michael.Srba@seznam.cz>
> 
> Add a driver for Samsung AMS452EF01 AMOLED panel, which makes use of their
> S6E88A0 controller. Basic functionality is supported, with the only notable 
> feature missing being backlight control. Backlight control on these panels is 
> complex and hard to make look nice, mainly courtesy of magic look up tables. If
> it is to be added, it should be with a separate patch.
> 
> Signed-off-by: Michael Srba <Michael.Srba@seznam.cz>
> ---
>  drivers/gpu/drm/panel/Kconfig                 |   6 +
>  drivers/gpu/drm/panel/Makefile                |   1 +
>  .../panel/panel-samsung-s6e88a0-ams452ef01.c  | 299 ++++++++++++++++++
>  3 files changed, 306 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index ae44ac2ec106..0c7d61f32b0e 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -275,6 +275,12 @@ config DRM_PANEL_SAMSUNG_S6E63M0
>  	  Say Y here if you want to enable support for Samsung S6E63M0
>  	  AMOLED LCD panel.
> 
> +config DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01
> +	tristate "Samsung AMS452EF01 panel with S6E88A0 DSI video mode controller"
> +	depends on OF
> +	select DRM_MIPI_DSI
> +	select VIDEOMODE_HELPERS
> +
>  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 7c4d3c581fd4..5b622fbe4014 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -28,6 +28,7 @@ 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-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01) += panel-samsung-s6e88a0-ams452ef01.o
>  obj-$(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-s6e88a0-ams452ef01.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c
> new file mode 100644
> index 000000000000..10eb1ffc1bba
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c
> @@ -0,0 +1,299 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +// Copyright (C) 2019, Michael Srba
> +
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +#include <video/mipi_display.h>

Order includes like this:

#include <linux/*>

#include <video/*>

#include <drm/drm_*>

Separate each block with a whitespace, and sort the lines alphabetically in ecah block.



> +
> +struct s6e88a0_ams452ef01 {
> +	struct drm_panel panel;
> +	struct mipi_dsi_device *dsi;
> +	struct regulator_bulk_data supplies[2];
> +	struct gpio_desc *reset_gpio;
> +
> +	bool prepared;
> +};
> +
> +static inline struct s6e88a0_ams452ef01 *to_s6e88a0_ams452ef01(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct s6e88a0_ams452ef01, panel);
> +}
> +
> +#define dsi_dcs_write_seq(dsi, seq...) do {				\
> +		static const u8 d[] = { seq };				\
> +		int ret;						\
> +		ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d));	\
> +		if (ret < 0)						\
> +			return ret;					\
> +	} while (0)
> +
> +static void s6e88a0_ams452ef01_reset(struct s6e88a0_ams452ef01 *ctx)
> +{
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	usleep_range(5000, 6000);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	usleep_range(1000, 2000);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	usleep_range(10000, 11000);
> +}
> +
> +static int s6e88a0_ams452ef01_on(struct s6e88a0_ams452ef01 *ctx)
> +{
> +	struct mipi_dsi_device *dsi = ctx->dsi;
> +	struct device *dev = &dsi->dev;
> +	int ret;
> +
> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	dsi_dcs_write_seq(dsi, 0xf0, 0x5a, 0x5a); // enable LEVEL2 commands
> +	dsi_dcs_write_seq(dsi, 0xcc, 0x4c); // set Pixel Clock Divider polarity
> +
> +	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to exit sleep mode: %d\n", ret);
> +		return ret;
> +	}
> +	msleep(120);
> +
> +	// set default brightness/gama
> +	dsi_dcs_write_seq(dsi, 0xca,
> +			  0x01, 0x00, 0x01, 0x00, 0x01, 0x00,	// V255 RR,GG,BB
> +			  0x80, 0x80, 0x80,			// V203 R,G,B
> +			  0x80, 0x80, 0x80,			// V151 R,G,B
> +			  0x80, 0x80, 0x80,			// V87  R,G,B
> +			  0x80, 0x80, 0x80,			// V51  R,G,B
> +			  0x80, 0x80, 0x80,			// V35  R,G,B
> +			  0x80, 0x80, 0x80,			// V23  R,G,B
> +			  0x80, 0x80, 0x80,			// V11  R,G,B
> +			  0x6b, 0x68, 0x71,			// V3   R,G,B
> +			  0x00, 0x00, 0x00);			// V1   R,G,B
> +	dsi_dcs_write_seq(dsi, 0xb2, 0x40, 0x0a, 0x17, 0x00, 0x0a); // set default Amoled Off Ratio
> +	dsi_dcs_write_seq(dsi, 0xb6, 0x2c, 0x0b); // set default elvss voltage
> +	dsi_dcs_write_seq(dsi, MIPI_DCS_WRITE_POWER_SAVE, 0x00);
> +	dsi_dcs_write_seq(dsi, 0xf7, 0x03); // gamma/aor update
> +	dsi_dcs_write_seq(dsi, 0xf0, 0xa5, 0xa5); // disable LEVEL2 commands
> +
> +	ret = mipi_dsi_dcs_set_display_on(dsi);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to set display on: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int s6e88a0_ams452ef01_off(struct s6e88a0_ams452ef01 *ctx)
> +{
> +	struct mipi_dsi_device *dsi = ctx->dsi;
> +	struct device *dev = &dsi->dev;
> +	int ret;
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	ret = mipi_dsi_dcs_set_display_off(dsi);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to set display off: %d\n", ret);
> +		return ret;
> +	}
> +	msleep(35);
> +
> +	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enter sleep mode: %d\n", ret);
> +		return ret;
> +	}
> +	msleep(120);
> +
> +	return 0;
> +}
> +
> +static int s6e88a0_ams452ef01_prepare(struct drm_panel *panel)
> +{
> +	struct s6e88a0_ams452ef01 *ctx = to_s6e88a0_ams452ef01(panel);
> +	struct device *dev = &ctx->dsi->dev;
> +	int ret;
> +
> +	if (ctx->prepared)
> +		return 0;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	s6e88a0_ams452ef01_reset(ctx);
> +
> +	ret = s6e88a0_ams452ef01_on(ctx);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to initialize panel: %d\n", ret);
> +		gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +		regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> +		return ret;
> +	}
> +
> +	ctx->prepared = true;
> +	return 0;
> +}
> +
> +static int s6e88a0_ams452ef01_unprepare(struct drm_panel *panel)
> +{
> +	struct s6e88a0_ams452ef01 *ctx = to_s6e88a0_ams452ef01(panel);
> +	struct device *dev = &ctx->dsi->dev;
> +	int ret;
> +
> +	if (!ctx->prepared)
> +		return 0;
> +
> +	ret = s6e88a0_ams452ef01_off(ctx);
> +	if (ret < 0)
> +		dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
> +
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> +
> +	ctx->prepared = false;
> +	return 0;
> +}
> +
> +static int s6e88a0_ams452ef01_enable(struct drm_panel *panel)
> +{
> +	return 0;
> +}
No need to add empty functions - drop it.

> +
> +static int s6e88a0_ams452ef01_disable(struct drm_panel *panel)
> +{
> +	return 0;
> +}
Ditto.

> +
> +static const struct drm_display_mode s6e88a0_ams452ef01_mode = {
> +	.clock = (540 + 88 + 4 + 20) * (960 + 14 + 2 + 8) * 60 / 1000,
> +	.hdisplay = 540,
> +	.hsync_start = 540 + 88,
> +	.hsync_end = 540 + 88 + 4,
> +	.htotal = 540 + 88 + 4 + 20,
> +	.vdisplay = 960,
> +	.vsync_start = 960 + 14,
> +	.vsync_end = 960 + 14 + 2,
> +	.vtotal = 960 + 14 + 2 + 8,
> +	.vrefresh = 60,
> +	.width_mm = 56,
> +	.height_mm = 100,
> +};
> +
> +static int s6e88a0_ams452ef01_get_modes(struct drm_panel *panel)
> +{
This will fail to build with drm-misc-next.
This functions now takes connector as argument.

> +	struct drm_display_mode *mode;
> +
> +	mode = drm_mode_duplicate(panel->drm, &s6e88a0_ams452ef01_mode);
panel->drm is gone. Use connector->dev

> +	if (!mode)
> +		return -ENOMEM;
> +
> +	drm_mode_set_name(mode);
> +
> +	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> +	panel->connector->display_info.width_mm = mode->width_mm;
> +	panel->connector->display_info.height_mm = mode->height_mm;
> +	drm_mode_probed_add(panel->connector, mode);
> +
> +	return 1;
> +}
> +
> +static const struct drm_panel_funcs s6e88a0_ams452ef01_panel_funcs = {
> +	.disable = s6e88a0_ams452ef01_disable,
> +	.unprepare = s6e88a0_ams452ef01_unprepare,
> +	.prepare = s6e88a0_ams452ef01_prepare,
> +	.enable = s6e88a0_ams452ef01_enable,
> +	.get_modes = s6e88a0_ams452ef01_get_modes,
> +};
> +
> +static int s6e88a0_ams452ef01_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	struct s6e88a0_ams452ef01 *ctx;
> +	int ret;
> +
> +	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +
> +	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) {
> +		dev_err(dev, "Failed to get regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(ctx->reset_gpio)) {
> +		ret = PTR_ERR(ctx->reset_gpio);
> +		dev_err(dev, "Failed to get reset-gpios: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ctx->dsi = dsi;
> +	mipi_dsi_set_drvdata(dsi, ctx);
> +
> +	dsi->lanes = 2;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST;
> +
> +	drm_panel_init(&ctx->panel, dev, &s6e88a0_ams452ef01_panel_funcs,
> +		       DRM_MODE_CONNECTOR_DSI);
> +
> +	ret = drm_panel_add(&ctx->panel);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to add panel: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = mipi_dsi_attach(dsi);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to attach to DSI host: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int s6e88a0_ams452ef01_remove(struct mipi_dsi_device *dsi)
> +{
> +	struct s6e88a0_ams452ef01 *ctx = mipi_dsi_get_drvdata(dsi);
> +	int ret;
> +
> +	ret = mipi_dsi_detach(dsi);
> +	if (ret < 0)
> +		dev_err(&dsi->dev, "Failed to detach from DSI host: %d\n", ret);
> +
> +	drm_panel_remove(&ctx->panel);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id s6e88a0_ams452ef01_of_match[] = {
> +	{ .compatible = "samsung,s6e88a0-ams452ef01" },
> +	{ }
Use:
	{ /* sentinel */ },


> +};
> +MODULE_DEVICE_TABLE(of, s6e88a0_ams452ef01_of_match);
> +
> +static struct mipi_dsi_driver s6e88a0_ams452ef01_driver = {
> +	.probe = s6e88a0_ams452ef01_probe,
> +	.remove = s6e88a0_ams452ef01_remove,
> +	.driver = {
> +		.name = "panel-s6e88a0-ams452ef01",
> +		.of_match_table = s6e88a0_ams452ef01_of_match,
> +	},
> +};
> +module_mipi_dsi_driver(s6e88a0_ams452ef01_driver);
> +
> +MODULE_AUTHOR("Michael Srba <Michael.Srba@seznam.cz>");
> +MODULE_DESCRIPTION("MIPI-DSI based Panel Driver for AMS452EF01 AMOLED LCD with a S6E88A0 controller");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.24.0
> 
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