Re: [PATCH 1/2] drm/panel: Add Ilitek ILI9341 parallel RGB panel driver

[Sam Ravnborg <sam@ravnborg.org>]

Hi Josef.

Thanks for the patch. A little late review follows.

Just a few thing, but please fix and resend.

	Sam

> +++ b/MAINTAINERS
> @@ -4800,6 +4800,12 @@ S:	Maintained
>  F:	drivers/gpu/drm/tinydrm/ili9225.c
>  F:	Documentation/devicetree/bindings/display/ilitek,ili9225.txt
>  
> +DRM DRIVER FOR ILITEK ILI9341 PANELS
> +M:	Josef Lusticky <josef@lusticky.cz>
> +S:	Maintained
> +F:	drivers/gpu/drm/panel/panel-ilitek-ili9341.c
> +F:	Documentation/devicetree/bindings/display/panel/ilitek,ili9341.txt
> +
>  DRM DRIVER FOR HX8357D PANELS
>  M:	Eric Anholt <eric@anholt.net>
>  T:	git git://anongit.freedesktop.org/drm/drm-misc

I recall entries in MAINTAINERS are supposed to be ordred alphabitically
after their title. So this needs to be fixed (H comes before I)

>  
> +config DRM_PANEL_ILITEK_IL9341
> +	tristate "Ilitek ILI9341 240x320 panels"
> +	depends on OF && SPI
> +	help
> +	  Say Y here if you want to enable support for Ilitek IL9341
> +	  QVGA (240x320) RGB panel.
The panel uses backlight - should it depens on BACKLIGHT?

> +
>  config DRM_PANEL_ILITEK_ILI9881C
>  	tristate "Ilitek ILI9881C-based panels"
>  	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index e7ab71968bbf..1df564018bc4 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_DRM_PANEL_ARM_VERSATILE) += panel-arm-versatile.o
>  obj-$(CONFIG_DRM_PANEL_LVDS) += panel-lvds.o
>  obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
>  obj-$(CONFIG_DRM_PANEL_ILITEK_IL9322) += panel-ilitek-ili9322.o
> +obj-$(CONFIG_DRM_PANEL_ILITEK_IL9341) += panel-ilitek-ili9341.o
>  obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
>  obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
>  obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9341.c b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
> new file mode 100644
> index 000000000000..51ed03140f8d
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
> @@ -0,0 +1,320 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Ilitek ILI9341 drm_panel driver
> + * 240RGBx320 dots resolution TFT LCD display
> + *
> + * This driver support the following panel configurations:
> + * - 18-bit parallel RGB interface
> + * - 8-bit SPI with Data/Command GPIO
> + *
> + * Copyright (C) 2019 Josef Lusticky <josef@lusticky.cz>
> + *
> + */
> +
> +#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/of_device.h>
> +#include <linux/spi/spi.h>
> +
> +#include <video/mipi_display.h>

Please include files in following blocks:

#include <linux/*>

#include <video/*>

#include <drm/*>

This matches what other panel drivers do today.
(It was only recently made the same for all drivers)


> +
> +/* ILI9341 extended register set */
> +#define ILI9341_IFMODE         0xB0 // clock polarity
> +#define ILI9341_IFCTL          0xF6 // interface conrol
> +#define ILI9341_PGAMCTRL       0xE0 // positive gamma control
> +#define ILI9341_NGAMCTRL       0xE1 // negative gamma control
> +
> +#define ILI9341_MADCTL_MV      BIT(5)
> +#define ILI9341_MADCTL_MX      BIT(6)
> +#define ILI9341_MADCTL_MY      BIT(7)
> +
> +/**
> + * struct ili9341_config - the display specific configuration
> + * @width_mm: physical panel width [mm]
> + * @height_mm: physical panel height [mm]
> + */
> +struct ili9341_config {
> +	u32 width_mm;
> +	u32 height_mm;
> +};
> +
> +struct ili9341 {
> +	const struct ili9341_config *conf;
> +	struct drm_panel panel;
> +	struct spi_device *spi;
> +	struct backlight_device *backlight;
> +	struct gpio_desc *dc_gpio;
> +	struct gpio_desc *reset_gpio;
> +};
No power-supply?
It is not in the binding, so likely not. But just wondering.

> +
> +static inline struct ili9341 *panel_to_ili9341(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct ili9341, panel);
> +}
> +
> +static int ili9341_spi_write_command(struct ili9341 *ili, u8 cmd)
> +{
> +	struct spi_transfer xfer = {
> +		.tx_buf = &cmd,
> +		.bits_per_word = 8,
> +		.len = 1
> +	};
> +	struct spi_message msg;
> +	spi_message_init(&msg);
> +	spi_message_add_tail(&xfer, &msg);
> +
> +	gpiod_set_value(ili->dc_gpio, 0);
> +
> +	return spi_sync(ili->spi, &msg);
> +}
> +
> +static int ili9341_spi_write_data(struct ili9341 *ili, u8 *data, size_t size)
> +{
> +	struct spi_transfer xfer = {
> +		.tx_buf = data,
> +		.bits_per_word = 8,
> +		.len = size
> +	};
> +
> +	struct spi_message msg;
> +	spi_message_init(&msg);
> +	spi_message_add_tail(&xfer, &msg);
> +
> +	gpiod_set_value(ili->dc_gpio, 1);
> +
> +	return spi_sync(ili->spi, &msg);
> +}
> +
> +#define ili9341_spi_write(ili, cmd, data...) \
> +({ \
> +	u8 d[] = { data }; \
> +	ili9341_spi_write_command(ili, cmd); \
> +	if (ARRAY_SIZE(d) > 0) \
> +		ili9341_spi_write_data(ili, d, ARRAY_SIZE(d)); \
> +})
> +
> +static int ili9341_deinit(struct drm_panel *panel, struct ili9341 *ili)
> +{
> +	ili9341_spi_write(ili, MIPI_DCS_SET_DISPLAY_OFF);
> +	ili9341_spi_write(ili, MIPI_DCS_ENTER_SLEEP_MODE);
> +	msleep(5);
> +	return 0;
> +}
> +
> +static int ili9341_init(struct drm_panel *panel, struct ili9341 *ili)
> +{
> +	/* HW / SW Reset display and wait */
> +	if (ili->reset_gpio) {
> +		gpiod_set_value(ili->reset_gpio, 0);
> +		usleep_range(20, 1000);
> +		gpiod_set_value(ili->reset_gpio, 1);
> +	} else {
> +		ili9341_spi_write(ili, MIPI_DCS_SOFT_RESET);
> +	}
> +	msleep(120);
> +
> +	/* Polarity */
> +	ili9341_spi_write(ili, ILI9341_IFMODE, 0xC0);
> +
> +	/* Interface control */
> +	ili9341_spi_write(ili, ILI9341_IFCTL, 0x09, 0x01, 0x26);
> +
> +	/* Pixel format */
> +	ili9341_spi_write(ili, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_18BIT << 4);
> +
> +	/* Gamma */
> +	ili9341_spi_write(ili, MIPI_DCS_SET_GAMMA_CURVE, 0x01);
> +	ili9341_spi_write(ili, ILI9341_PGAMCTRL,
> +		0x0f, 0x31, 0x2b, 0x0c, 0x0e, 0x08, 0x4e, 0xf1,
> +		0x37, 0x07, 0x10, 0x03, 0x0e, 0x09, 0x00);
> +	ili9341_spi_write(ili, ILI9341_NGAMCTRL,
> +		0x00, 0x0e, 0x14, 0x03, 0x11, 0x07, 0x31, 0xc1,
> +		0x48, 0x08, 0x0f, 0x0c, 0x31, 0x36, 0x0f);
> +
> +	/* Rotation */
> +	ili9341_spi_write(ili, MIPI_DCS_SET_ADDRESS_MODE, ILI9341_MADCTL_MX);
> +
> +	/* Exit sleep mode */
> +	ili9341_spi_write(ili, MIPI_DCS_EXIT_SLEEP_MODE);
> +	msleep(120);
> +
> +	ili9341_spi_write(ili, MIPI_DCS_SET_DISPLAY_ON);
> +
> +	return 0;
> +}
> +
> +static int ili9341_unprepare(struct drm_panel *panel)
> +{
> +	struct ili9341 *ili = panel_to_ili9341(panel);
> +	return ili9341_deinit(panel, ili);
> +}
> +
> +static int ili9341_prepare(struct drm_panel *panel)
> +{
> +	struct ili9341 *ili = panel_to_ili9341(panel);
> +	int ret;
> +
> +	ret = ili9341_init(panel, ili);
> +	if (ret < 0)
> +		ili9341_unprepare(panel);
> +	return ret;
> +}
> +
> +static int ili9341_enable(struct drm_panel *panel)
> +{
> +	struct ili9341 *ili = panel_to_ili9341(panel);
> +	return backlight_enable(ili->backlight);
> +}
> +
> +static int ili9341_disable(struct drm_panel *panel)
> +{
> +	struct ili9341 *ili = panel_to_ili9341(panel);
> +	return backlight_disable(ili->backlight);
> +}
> +
> +static const struct drm_display_mode prgb_240x320_mode = {
> +	.clock = 6350,
> +
> +	.hdisplay = 240,
> +	.hsync_start = 240 + 10,
> +	.hsync_end = 240 + 10 + 10,
> +	.htotal = 240 + 10 + 10 + 20,
> +
> +	.vdisplay = 320,
> +	.vsync_start = 320 + 4,
> +	.vsync_end = 320 + 4 + 2,
> +	.vtotal = 320 + 4 + 2 + 2,
> +
> +	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED
> +};
> +
> +static int ili9341_get_modes(struct drm_panel *panel)
> +{
> +	struct drm_connector *connector = panel->connector;
> +	struct ili9341 *ili = panel_to_ili9341(panel);
> +	struct drm_display_mode *mode;
> +
> +	mode = drm_mode_duplicate(panel->drm, &prgb_240x320_mode);
check if drm_mode_duplicate() fails, and handle this.
See how other drivers do it.

> +	drm_mode_set_name(mode);
> +
> +	mode->width_mm = ili->conf->width_mm;
> +	mode->height_mm = ili->conf->height_mm;
> +
> +	strncpy(connector->display_info.name, "ILI9341 TFT LCD driver\0",
> +		DRM_DISPLAY_INFO_LEN);
> +	connector->display_info.width_mm = mode->width_mm;
> +	connector->display_info.height_mm = mode->height_mm;
> +	connector->display_info.bus_flags |= DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_POSEDGE |
> +		DRM_BUS_FLAG_SYNC_NEGEDGE;
> +
> +	drm_mode_probed_add(connector, mode);
> +
> +	return 1; /* Number of modes */
> +}
> +
> +static const struct drm_panel_funcs ili9341_drm_funcs = {
> +	.disable = ili9341_disable,
> +	.unprepare = ili9341_unprepare,
> +	.prepare = ili9341_prepare,
> +	.enable = ili9341_enable,
> +	.get_modes = ili9341_get_modes,
> +};
> +
> +static int ili9341_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	struct ili9341 *ili;
> +	int ret;
> +
> +	ili = devm_kzalloc(dev, sizeof(struct ili9341), GFP_KERNEL);
> +	if (!ili)
> +		return -ENOMEM;
> +
> +	spi_set_drvdata(spi, ili);
> +
> +	ili->spi = spi;
> +
> +	/*
> +	 * Every new incarnation of this display must have a unique
> +	 * data entry for the system in this driver.
> +	 */
> +	ili->conf = of_device_get_match_data(dev);
> +	if (!ili->conf) {
> +		DRM_DEV_ERROR(dev, "missing device configuration\n");
> +		return -ENODEV;
> +	}
> +
> +	ili->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ili->reset_gpio)) {
> +		DRM_DEV_ERROR(dev, "failed to get reset gpio\n");
> +		return PTR_ERR(ili->reset_gpio);
> +	}
> +
> +	ili->dc_gpio = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
> +	if (IS_ERR(ili->dc_gpio)) {
> +		DRM_DEV_ERROR(dev, "failed to get dc gpio\n");
> +		return PTR_ERR(ili->dc_gpio);
> +	}
> +
> +	ili->backlight = devm_of_find_backlight(dev);
> +	if (IS_ERR(ili->backlight)) {
> +		DRM_DEV_ERROR(dev, "failed to get backlight\n");
> +		return PTR_ERR(ili->backlight);
> +	}
> +
> +	ret = spi_setup(spi);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(dev, "spi setup failed\n");
> +		return ret;
> +	}
> +
> +	drm_panel_init(&ili->panel);
> +	ili->panel.dev = dev;
> +	ili->panel.funcs = &ili9341_drm_funcs;
> +
> +	return drm_panel_add(&ili->panel);
> +}
> +
> +static int ili9341_remove(struct spi_device *spi)
> +{
> +	struct ili9341 *ili = spi_get_drvdata(spi);
> +
> +	drm_panel_remove(&ili->panel);
> +
> +	ili9341_disable(&ili->panel);
> +	ili9341_unprepare(&ili->panel);
> +
> +	return 0;
> +}
> +
> +static const struct ili9341_config dt024ctft_data = {
> +	.width_mm = 37,
> +	.height_mm = 49,
> +};
> +
> +static const struct of_device_id ili9341_of_match[] = {
> +	{ .compatible = "displaytech,dt024ctft", .data = &dt024ctft_data },
> +	{ }
Many drivers add the comment { /* sentinel */ } to document this is a
mandatory end marker.

> +};
> +MODULE_DEVICE_TABLE(of, ili9341_of_match);
> +
> +static struct spi_driver ili9341_driver = {
> +	.probe = ili9341_probe,
> +	.remove = ili9341_remove,
> +	.driver = {
> +		.name = "panel-ilitek-ili9341",
> +		.of_match_table = ili9341_of_match,
> +	},
> +};
> +module_spi_driver(ili9341_driver);
> +
> +MODULE_AUTHOR("Josef Lusticky <josef@lusticky.cz>");
> +MODULE_DESCRIPTION("ILI9341 LCD panel driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.20.1
> 
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