Re: [PATCH 2/2] drm/panel: Add driver for sitronix ST7789V panel

On Fri, Feb 03, 2017 at 10:59:06AM +0100, Maxime Ripard wrote:

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

drivers/gpu/drm/panel/Kconfig | 4 +- drivers/gpu/drm/panel/Makefile | 1 +- drivers/gpu/drm/panel/panel-sitronix-st7789v.c | 435 ++++++++++++++++++- 3 files changed, 440 insertions(+), 0 deletions(-) create mode 100644 drivers/gpu/drm/panel/panel-sitronix-st7789v.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig index 62aba976e744..d07b996a07b8 100644 --- a/drivers/gpu/drm/panel/Kconfig +++ b/drivers/gpu/drm/panel/Kconfig @@ -81,4 +81,8 @@ config DRM_PANEL_SHARP_LS043T1LE01 Say Y here if you want to enable support for Sharp LS043T1LE01 qHD (540x960) DSI panel as found on the Qualcomm APQ8074 Dragonboard

+config DRM_PANEL_SITRONIX_ST7789V

• tristate "Sitronx ST7789V panel"

"Sitronix"

• depends on OF && SPI

Maybe be more verbose here about what kind of panel it is, and what resolution it provides.

endmenu diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile index a5c7ec0236e0..41b245d39984 100644 --- a/drivers/gpu/drm/panel/Makefile +++ b/drivers/gpu/drm/panel/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o obj-$(CONFIG_DRM_PANEL_SHARP_LS043T1LE01) += panel-sharp-ls043t1le01.o +obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c new file mode 100644 index 000000000000..aab817b55aa6 --- /dev/null +++ b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c @@ -0,0 +1,435 @@ +/*

• • Copyright (C) 2017 Free Electrons
• • This program is free software; you can redistribute it and/or
• • modify it under the terms of the GNU General Public License version
• • 2 as published by the Free Software Foundation.
• */

+#include <drm/drmP.h> +#include <drm/drm_panel.h>

+#include <linux/gpio/consumer.h> +#include <linux/spi/spi.h>

I prefer linux/* headers to go first.

+#define ST7789V_SLPIN_CMD 0x10

+#define ST7789V_SLPOUT_CMD 0x11

+#define ST7789V_INVON_CMD 0x21

+#define ST7789V_DISPOFF_CMD 0x28

+#define ST7789V_DISPON_CMD 0x29

+#define ST7789V_MADCTL_CMD 0x36

+#define ST7789V_COLMOD_CMD 0x3a +#define ST7789V_COLMOD_RGB_FMT_18BITS (6 << 4) +#define ST7789V_COLMOD_CTRL_FMT_18BITS (6 << 0)

MIPI_DCS_PIXEL_FMT_18BIT?

[...]

+struct st7789v {

• struct drm_panel panel;
• struct spi_device *spi;
• struct gpio_desc *reset;
• struct backlight_device *backlight;

+};

+enum st7789v_prefix {

• ST7789V_COMMAND = 0,
• ST7789V_DATA = 1,

+};

+static inline struct st7789v *panel_to_st7789v(struct drm_panel *panel) +{

• return container_of(panel, struct st7789v, panel);

+}

+static int st7789v_spi_write(struct st7789v *ctx, u8 prefix, u8 data)

Why aren't you using the proper type here for prefix?

+{

• struct spi_transfer xfer = { };
• struct spi_message msg;
• u16 txbuf = ((prefix & 1) << 8) | data;
• spi_message_init(&msg);
• xfer.tx_buf = &txbuf;
• xfer.bits_per_word = 9;
• xfer.len = sizeof(txbuf);
• spi_message_add_tail(&xfer, &msg);
• return spi_sync(ctx->spi, &msg);

+}

+static int st7789v_write_command(struct st7789v *ctx, u8 cmd) +{

• return st7789v_spi_write(ctx, ST7789V_COMMAND, cmd);

+}

+static int st7789v_write_data(struct st7789v *ctx, u8 cmd) +{

• return st7789v_spi_write(ctx, ST7789V_DATA, cmd);

+}

+static int st7789v_write_command_data(struct st7789v *ctx, u8 cmd,

• 		      unsigned long n_data, ...)
  

+{

• va_list ap;
• int i;
• st7789v_write_command(ctx, cmd);
• va_start(ap, n_data);
• for (i = 0; i < n_data; i++)

• st7789v_write_data(ctx, va_arg(ap, int));
  

• va_end(ap);
• return 0;

+}

Please propagate error codes from st7789v_write_{command,data}(). And you should abort early on errors.

+#define NUMARGS(...) (sizeof((int[]){__VA_ARGS__}) / sizeof(int)) +#define st7789v_send(ctx, cmd, ...) \

• st7789v_write_command_data(ctx, cmd, NUMARGS(__VA_ARGS__), \

• 		   ##__VA_ARGS__)
  

How is this going to work if any of the arguments happens to not be an int? What if you have something like this:

u8 value = 0x2;

st7789v_write_command_data(ctx, cmd, 0x1, value, 0x3);

? Wouldn't that invalidly read "value" as int and wrongly increment the ap by three bytes too many?

+static int st7789v_prepare(struct drm_panel *panel) +{

• struct st7789v *ctx = panel_to_st7789v(panel);
• gpiod_set_value(ctx->reset, 1);
• msleep(30);
• gpiod_set_value(ctx->reset, 0);
• msleep(120);
• st7789v_send(ctx, ST7789V_SLPOUT_CMD);
• /* We need to wait 120ms after a sleep out command */
• msleep(120);
• st7789v_send(ctx, ST7789V_MADCTL_CMD, 0);
• st7789v_send(ctx, ST7789V_COLMOD_CMD,

•      ST7789V_COLMOD_CTRL_FMT_18BITS |
  

•      ST7789V_COLMOD_RGB_FMT_18BITS);
  

• st7789v_send(ctx, ST7789V_PORCTRL_CMD,

•      0xc,		/* Backporch, normal mode*/
  

•      0xc,		/* Frontporch, normal mode */
  

•      0,			/* Disable separate porch control */
  

•      ST7789V_PORCTRL_IDLE_BP(3) |
  

•      ST7789V_PORCTRL_IDLE_FP(3),
  

•      ST7789V_PORCTRL_PARTIAL_BP(3) |
  

•      ST7789V_PORCTRL_PARTIAL_FP(3));
  

• st7789v_send(ctx, ST7789V_GCTRL_CMD,

•      ST7789V_GCTRL_VGLS(5) | ST7789V_GCTRL_VGHS(3));
  

• st7789v_send(ctx, ST7789V_VCOMS_CMD, 0x2b);
• st7789v_send(ctx, ST7789V_LCMCTRL_CMD, ST7789V_LCMCTRL_XMH |

•      ST7789V_LCMCTRL_XMX | ST7789V_LCMCTRL_XBGR);
  

• st7789v_send(ctx, ST7789V_VDVVRHEN_CMD, ST7789V_VDVVRHEN_CMDEN);
• st7789v_send(ctx, ST7789V_VRHS_CMD, 0xf);
• st7789v_send(ctx, ST7789V_VDVS_CMD, 0x20);
• st7789v_send(ctx, ST7789V_FRCTRL2_CMD, 0xf);
• st7789v_send(ctx, ST7789V_PWCTRL1_CMD, ST7789V_PWCTRL1_MAGIC,

•      ST7789V_PWCTRL1_AVDD(2) | ST7789V_PWCTRL1_AVCL(2) |
  

•      ST7789V_PWCTRL1_VDS(1));
  

• st7789v_send(ctx, ST7789V_PVGAMCTRL_CMD,

•      ST7789V_PVGAMCTRL_VP63(0xd),
  

•      ST7789V_PVGAMCTRL_VP1(0xca),
  

•      ST7789V_PVGAMCTRL_VP2(0xe),
  

•      ST7789V_PVGAMCTRL_VP4(8),
  

•      ST7789V_PVGAMCTRL_VP6(9),
  

•      ST7789V_PVGAMCTRL_VP13(7),
  

•      ST7789V_PVGAMCTRL_VP20(0x2d),
  

•      ST7789V_PVGAMCTRL_VP27(0xb) | ST7789V_PVGAMCTRL_VP36(3),
  

•      ST7789V_PVGAMCTRL_VP43(0x3d),
  

•      ST7789V_PVGAMCTRL_JP1(3) | ST7789V_PVGAMCTRL_VP50(4),
  

•      ST7789V_PVGAMCTRL_VP57(0xa),
  

•      ST7789V_PVGAMCTRL_VP59(0xa),
  

•      ST7789V_PVGAMCTRL_VP61(0x1b),
  

•      ST7789V_PVGAMCTRL_VP62(0x28));
  

• st7789v_send(ctx, ST7789V_NVGAMCTRL_CMD,

•      ST7789V_NVGAMCTRL_VN63(0xd),
  

•      ST7789V_NVGAMCTRL_VN1(0xca),
  

•      ST7789V_NVGAMCTRL_VN2(0xf),
  

•      ST7789V_NVGAMCTRL_VN4(8),
  

•      ST7789V_NVGAMCTRL_VN6(8),
  

•      ST7789V_NVGAMCTRL_VN13(7),
  

•      ST7789V_NVGAMCTRL_VN20(0x2e),
  

•      ST7789V_NVGAMCTRL_VN27(0xc) | ST7789V_NVGAMCTRL_VN36(5),
  

•      ST7789V_NVGAMCTRL_VN43(0x40),
  

•      ST7789V_NVGAMCTRL_JN1(3) | ST7789V_NVGAMCTRL_VN50(4),
  

•      ST7789V_NVGAMCTRL_VN57(9),
  

•      ST7789V_NVGAMCTRL_VN59(0xb),
  

•      ST7789V_NVGAMCTRL_VN61(0x1b),
  

•      ST7789V_NVGAMCTRL_VN62(0x28));
  

• st7789v_send(ctx, ST7789V_INVON_CMD);
• st7789v_send(ctx, ST7789V_RAMCTRL_CMD,

•      ST7789V_RAMCTRL_DM_RGB | ST7789V_RAMCTRL_RM_RGB,
  

•      ST7789V_RAMCTRL_EPF(3) | ST7789V_RAMCTRL_MAGIC);
  

• st7789v_send(ctx, ST7789V_RGBCTRL_CMD,

•      ST7789V_RGBCTRL_WO | ST7789V_RGBCTRL_RCM(2) |
  

•      ST7789V_RGBCTRL_VSYNC_HIGH | ST7789V_RGBCTRL_HSYNC_HIGH |
  

•      ST7789V_RGBCTRL_PCLK_HIGH,
  

•      ST7789V_RGBCTRL_VBP(8), ST7789V_RGBCTRL_HBP(20));
  

• return 0;

+}

Please check for errors in all of the above.

+static int st7789v_probe(struct spi_device *spi) +{

• struct device_node *backlight;
• struct st7789v *ctx;
• int ret;
• ctx = devm_kzalloc(&spi->dev, sizeof(*ctx), GFP_KERNEL);
• if (!ctx)

• return -ENOMEM;
  

• spi_set_drvdata(spi, ctx);
• ctx->spi = spi;
• ctx->panel.dev = &spi->dev;
• ctx->panel.funcs = &st7789v_drm_funcs;
• ctx->reset = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_LOW);
• if (IS_ERR(ctx->reset)) {

• dev_err(&spi->dev, "Couldn't get our reset line\n");
  

• return PTR_ERR(ctx->reset);
  

• }
• backlight = of_parse_phandle(spi->dev.of_node, "backlight", 0);
• if (backlight) {

• ctx->backlight = of_find_backlight_by_node(backlight);
  

• of_node_put(backlight);
  

• if (!ctx->backlight)
  

• 	return -EPROBE_DEFER;
  

• }

This could make use of one of the helpers that Noralf had sent earlier for TinyDRM. That is, if it weren't specific to TinyDRM.

Thierry