Re: [PATCH v2 2/2] drm/panel: Add a driver for Samsung s6e88a0-ams452ef01 panel

[Sam Ravnborg <sam@ravnborg.org>]

Hi Michael.

On Thu, Jan 30, 2020 at 08:02:31PM +0100, Michael Srba wrote:
> Sending this with thunderbird, fingers crossed for no formatting issues
Readable...

> 
> Hi,
> I've taken about two weeks to send zinitix v2, and haven't heard about
> that or
> v3 yet, so combined with how easy it was to address the issues, I didn't
> want
> to risk that was the reason :)
> I'm not sure how I should make the subject shorter, it's already pretty
> barebones, so if it has to be done, I assume you would have a suggestion
> on what
> is not as important as it seems to me?
> I'm also not sure if splitting the comment on line 78 to three lines
> (two seem
> to not suffice) wouldn't be even worse than leaving it like this? Or
> should I
> have it more to the left so that it fits on just two lines?
> Similarly, I'm not sure what the convention for splitting would be on
> line 25,
> since I saw the line breaks placed mostly after a whole function parameter.
> Actually, for all of the above-80 lines except the one that I missed when
> updating it today I don't really know how to handle them... except maybe
> line
> 139, I guess I missed that since it's off-by-one

Address what you think needs to be addressed.
If I feel strong about some of the remaining warnings I
will fix when applying.
And let you know what I did if this is the case.

	Sam


> 
> On 30. 01. 20 19:28, Sam Ravnborg wrote:
> > Hi Micahel.
> >
> > Thanks for the quick feedback.
> >
> > Please address checkpatch warnings.
> >
> > be2b44c76320 (HEAD -> drm-misc-next) drm/panel: Add a driver for Samsung s6e88a0-ams452ef01 panel
> > -:7: WARNING:COMMIT_MESSAGE: Missing commit description - Add an appropriate one
> >
> > -:40: WARNING:FILE_PATH_CHANGES: added, moved or deleted file(s), does MAINTAINERS need updating?
> > #40: 
> > new file mode 100644
> >
> > -:69: WARNING:LONG_LINE: line over 80 characters
> > #69: FILE: drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c:25:
> > +static inline struct s6e88a0_ams452ef01 *to_s6e88a0_ams452ef01(struct drm_panel *panel)
> >
> > -:74: WARNING:MACRO_WITH_FLOW_CONTROL: Macros with flow control statements should be avoided
> > #74: FILE: drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c:30:
> > +#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)
> >
> > -:122: WARNING:LONG_LINE_COMMENT: line over 80 characters
> > #122: FILE: drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c:78:
> > +	dsi_dcs_write_seq(dsi, 0xb2, 0x40, 0x0a, 0x17, 0x00, 0x0a); // set default Amoled Off Ratio
> >
> > -:183: WARNING:LONG_LINE: line over 80 characters
> > #183: FILE: drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c:139:
> > +		regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> >
> > -:226: WARNING:LONG_LINE: line over 80 characters
> > #226: FILE: drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c:182:
> > +static int s6e88a0_ams452ef01_get_modes(struct drm_panel *panel, struct drm_connector *connector)
> >
> > total: 0 errors, 7 warnings, 0 checks, 308 lines checked
> >
> >
> >
> > Use: dim checkpatch" if you have dim.
> > Otherwise use checkpatch -q --emacs --strict --show-types
> >
> > Ignore the warning "MACRO_WITH_FLOW_CONTROL" - as this seems legit in this use-case.
> >
> > 	Sam
> >
> > On Thu, Jan 30, 2020 at 06:11:28PM +0100, michael.srba@seznam.cz wrote:
> >> From: Michael Srba <Michael.Srba@seznam.cz>
> >>
> >> Signed-off-by: Michael Srba <Michael.Srba@seznam.cz>
> >> ---
> >> Changes since v1: reorder includes; remove empty functions; fix after rebasing
> >> ---
> >>  drivers/gpu/drm/panel/Kconfig                 |   6 +
> >>  drivers/gpu/drm/panel/Makefile                |   1 +
> >>  .../panel/panel-samsung-s6e88a0-ams452ef01.c  | 289 ++++++++++++++++++
> >>  3 files changed, 296 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..49d3f6d0f137
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams452ef01.c
> >> @@ -0,0 +1,289 @@
> >> +// SPDX-License-Identifier: GPL-2.0-only
> >> +// Copyright (C) 2019, Michael Srba
> >> +
> >> +#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>
> >> +
> >> +#include <drm/drm_mipi_dsi.h>
> >> +#include <drm/drm_modes.h>
> >> +#include <drm/drm_panel.h>
> >> +
> >> +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 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, struct drm_connector *connector)
> >> +{
> >> +	struct drm_display_mode *mode;
> >> +
> >> +	mode = drm_mode_duplicate(connector->dev, &s6e88a0_ams452ef01_mode);
> >> +	if (!mode)
> >> +		return -ENOMEM;
> >> +
> >> +	drm_mode_set_name(mode);
> >> +
> >> +	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> >> +	connector->display_info.width_mm = mode->width_mm;
> >> +	connector->display_info.height_mm = mode->height_mm;
> >> +	drm_mode_probed_add(connector, mode);
> >> +
> >> +	return 1;
> >> +}
> >> +
> >> +static const struct drm_panel_funcs s6e88a0_ams452ef01_panel_funcs = {
> >> +	.unprepare = s6e88a0_ams452ef01_unprepare,
> >> +	.prepare = s6e88a0_ams452ef01_prepare,
> >> +	.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" },
> >> +	{ /* 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