Hi Geert.
Good to see we add more functionality to the smallest driver in DRM.
The patch triggered a few comments - see below.
Some comments relates to the original driver - and not your changes.
Sam
On Thu, Jan 02, 2020 at 03:12:46PM +0100, Geert Uytterhoeven wrote:
> Add support for the Okaya RH128128T display to the st7735r driver.
>
> The RH128128T is a 128x128 1.44" TFT display driven by a Sitronix
> ST7715R TFT Controller/Driver. The latter is very similar to the
> ST7735R, and can be handled by the existing st7735r driver.
As a general comment - it would have eased review if this was split
in two patches.
One patch to introduce the infrastructure to deal with another set of
controller/display and one patch introducing the new combination.
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> drivers/gpu/drm/tiny/st7735r.c | 65 ++++++++++++++++++++++++++++------
> 1 file changed, 55 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/tiny/st7735r.c b/drivers/gpu/drm/tiny/st7735r.c
> index 3f4487c716848cf8..05d162e76d8481e5 100644
> --- a/drivers/gpu/drm/tiny/st7735r.c
> +++ b/drivers/gpu/drm/tiny/st7735r.c
> @@ -1,8 +1,9 @@
> // SPDX-License-Identifier: GPL-2.0+
> /*
> - * DRM driver for Sitronix ST7735R panels
> + * DRM driver for Sitronix ST7715R/ST7735R panels
This comment could describe the situation a little better.
This is a sitronix st7735r controller with a jianda jd-t18003-t01
display.
Or a sitronix st7715r controller with a okaya rh128128t display.
> *
> * Copyright 2017 David Lechner <david@xxxxxxxxxxxxxx>
> + * Copyright (C) 2019 Glider bvba
> */
>
> #include <linux/backlight.h>
> @@ -10,6 +11,7 @@
> #include <linux/dma-buf.h>
> #include <linux/gpio/consumer.h>
> #include <linux/module.h>
> +#include <linux/of_device.h>
> #include <linux/property.h>
> #include <linux/spi/spi.h>
> #include <video/mipi_display.h>
> @@ -37,12 +39,28 @@
> #define ST7735R_MY BIT(7)
> #define ST7735R_MX BIT(6)
> #define ST7735R_MV BIT(5)
> +#define ST7735R_RGB BIT(3)
> +
> +struct st7735r_cfg {
> + const struct drm_display_mode mode;
> + unsigned int left_offset;
> + unsigned int top_offset;
> + unsigned int write_only:1;
> + unsigned int rgb:1; /* RGB (vs. BGR) */
> +};
> +
> +struct st7735r_priv {
> + struct mipi_dbi_dev dbidev; /* Must be first for .release() */
> + unsigned int rgb:1;
> +};
The structs here uses "st7735r" as the generic prefix.
But the rest of this file uses "jd_t18003_t01" as the generic prefix.
It would help readability if the same prefix is used for the common
stuff everywhere.
struct st7735r_priv includes "rgb" which is copied from struct
st7735r_cfg.
Maybe just add a const pointer to struct st7735r_cfg,
so when we later add more configuration items we do not need to have two
copies. And then ofc drop st7735r_priv.rgb.
>
> static void jd_t18003_t01_pipe_enable(struct drm_simple_display_pipe *pipe,
> struct drm_crtc_state *crtc_state,
> struct drm_plane_state *plane_state)
> {
> struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
> + struct st7735r_priv *priv = container_of(dbidev, struct st7735r_priv,
> + dbidev);
> struct mipi_dbi *dbi = &dbidev->dbi;
> int ret, idx;
> u8 addr_mode;
> @@ -87,6 +105,10 @@ static void jd_t18003_t01_pipe_enable(struct drm_simple_display_pipe *pipe,
> addr_mode = ST7735R_MY | ST7735R_MV;
> break;
> }
> +
> + if (priv->rgb)
> + addr_mode |= ST7735R_RGB;
> +
> mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
> mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT,
> MIPI_DCS_PIXEL_FMT_16BIT);
> @@ -116,8 +138,17 @@ static const struct drm_simple_display_pipe_funcs jd_t18003_t01_pipe_funcs = {
> .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
> };
>
> -static const struct drm_display_mode jd_t18003_t01_mode = {
> - DRM_SIMPLE_MODE(128, 160, 28, 35),
> +static const struct st7735r_cfg jd_t18003_t01_cfg = {
> + .mode = { DRM_SIMPLE_MODE(128, 160, 28, 35) },
> + /* Cannot read from Adafruit 1.8" display via SPI */
> + .write_only = true,
> +};
> +
> +static const struct st7735r_cfg rh128128t_cfg = {
> + .mode = { DRM_SIMPLE_MODE(128, 128, 25, 26) },
> + .left_offset = 2,
> + .top_offset = 3,
> + .rgb = true,
> };
>
> DEFINE_DRM_GEM_CMA_FOPS(st7735r_fops);
> @@ -136,13 +167,14 @@ static struct drm_driver st7735r_driver = {
> };
>
> static const struct of_device_id st7735r_of_match[] = {
> - { .compatible = "jianda,jd-t18003-t01" },
> + { .compatible = "jianda,jd-t18003-t01", .data = &jd_t18003_t01_cfg },
> + { .compatible = "okaya,rh128128t", .data = &rh128128t_cfg },
> { },
{ /* sentinel },
Also - which is not a new thing - this fails to check that we have the
correct combination of two compatibles.
>From the binding:
Must be one of the following combinations:
- "jianda,jd-t18003-t01", "sitronix,st7735r"
- "okaya,rh128128t", "sitronix,st7715r"
> };
> MODULE_DEVICE_TABLE(of, st7735r_of_match);
>
> static const struct spi_device_id st7735r_id[] = {
> - { "jd-t18003-t01", 0 },
> + { "jd-t18003-t01", (uintptr_t)&jd_t18003_t01_cfg },
> { },
{ /* sentinel */ },
Do we need an entry for "okaya,rh128128t" here?
Note: I have not fully understood how MODULE_DEVICE_TABLE()
works - so forgive me my ignorance.
> };
> MODULE_DEVICE_TABLE(spi, st7735r_id);
> @@ -150,17 +182,26 @@ MODULE_DEVICE_TABLE(spi, st7735r_id);
> static int st7735r_probe(struct spi_device *spi)
> {
> struct device *dev = &spi->dev;
> + const struct st7735r_cfg *cfg;
> struct mipi_dbi_dev *dbidev;
> + struct st7735r_priv *priv;
> struct drm_device *drm;
> struct mipi_dbi *dbi;
> struct gpio_desc *dc;
> u32 rotation = 0;
> int ret;
>
> - dbidev = kzalloc(sizeof(*dbidev), GFP_KERNEL);
> - if (!dbidev)
> + cfg = of_device_get_match_data(&spi->dev);
> + if (!cfg)
> + cfg = (void *)spi_get_device_id(spi)->driver_data;
> +
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> return -ENOMEM;
>
> + dbidev = &priv->dbidev;
> + priv->rgb = cfg->rgb;
> +
> dbi = &dbidev->dbi;
> drm = &dbidev->drm;
> ret = devm_drm_dev_init(dev, drm, &st7735r_driver);
> @@ -193,10 +234,14 @@ static int st7735r_probe(struct spi_device *spi)
> if (ret)
> return ret;
>
> - /* Cannot read from Adafruit 1.8" display via SPI */
> - dbi->read_commands = NULL;
> + if (cfg->write_only)
> + dbi->read_commands = NULL;
> +
> + dbidev->left_offset = cfg->left_offset;
> + dbidev->top_offset = cfg->top_offset;
>
> - ret = mipi_dbi_dev_init(dbidev, &jd_t18003_t01_pipe_funcs, &jd_t18003_t01_mode, rotation);
> + ret = mipi_dbi_dev_init(dbidev, &jd_t18003_t01_pipe_funcs, &cfg->mode,
> + rotation);
> if (ret)
> return ret;
>
> --
> 2.17.1
>
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