Re: [PATCH v1 2/2] drm/tinydrm: add driver for ST7735R panels

Den 29.11.2017 04.01, skrev David Lechner:

This adds a new driver for Sitronix ST7735R display panels.

This has been tested using an Adafruit 1.8" TFT.

Signed-off-by: David Lechner david@lechnology.com

MAINTAINERS | 6 + drivers/gpu/drm/tinydrm/Kconfig | 10 ++ drivers/gpu/drm/tinydrm/Makefile | 1 + drivers/gpu/drm/tinydrm/st7735r.c | 237 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 254 insertions(+) create mode 100644 drivers/gpu/drm/tinydrm/st7735r.c

diff --git a/MAINTAINERS b/MAINTAINERS index a174632..9c7707e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4462,6 +4462,12 @@ S: Maintained F: drivers/gpu/drm/tinydrm/st7586.c F: Documentation/devicetree/bindings/display/st7586.txt

+DRM DRIVER FOR SITRONIX ST7735R PANELS +M: David Lechner david@lechnology.com

I know we haven't done this in the other tinydrm drivers, but I think we should start adding which tree the development is happening in:

T:    git git://anongit.freedesktop.org/drm/drm-misc

+S: Maintained +F: drivers/gpu/drm/tinydrm/st7735r.c +F: Documentation/devicetree/bindings/display/st7735r.txt

• DRM DRIVER FOR TDFX VIDEO CARDS S: Orphan / Obsolete F: drivers/gpu/drm/tdfx/

diff --git a/drivers/gpu/drm/tinydrm/Kconfig b/drivers/gpu/drm/tinydrm/Kconfig index 90c5bd5..b0e567d 100644 --- a/drivers/gpu/drm/tinydrm/Kconfig +++ b/drivers/gpu/drm/tinydrm/Kconfig @@ -52,3 +52,13 @@ config TINYDRM_ST7586 * LEGO MINDSTORMS EV3

 If M is selected the module will be called st7586.

+config TINYDRM_ST7735R

• tristate "DRM support for Sitronix ST7735R display panels"
• depends on DRM_TINYDRM && SPI
• select TINYDRM_MIPI_DBI
• help

•  DRM driver Sitronix ST7735R with one of the following LCDs:
  

•  * JD-T18003-T01 1.8" 128x160 TFT
  

•  If M is selected the module will be called st7735r.
  

diff --git a/drivers/gpu/drm/tinydrm/Makefile b/drivers/gpu/drm/tinydrm/Makefile index 8aeee53..49a1119 100644 --- a/drivers/gpu/drm/tinydrm/Makefile +++ b/drivers/gpu/drm/tinydrm/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_TINYDRM_ILI9225) += ili9225.o obj-$(CONFIG_TINYDRM_MI0283QT) += mi0283qt.o obj-$(CONFIG_TINYDRM_REPAPER) += repaper.o obj-$(CONFIG_TINYDRM_ST7586) += st7586.o +obj-$(CONFIG_TINYDRM_ST7735R) += st7735r.o diff --git a/drivers/gpu/drm/tinydrm/st7735r.c b/drivers/gpu/drm/tinydrm/st7735r.c new file mode 100644 index 0000000..6435b00 --- /dev/null +++ b/drivers/gpu/drm/tinydrm/st7735r.c @@ -0,0 +1,237 @@ +/*

• • DRM driver for Sitronix ST7735R panels
• • Copyright 2017 David Lechner david@lechnology.com
• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License as published by
• • the Free Software Foundation; either version 2 of the License, or
• • (at your option) any later version.
• */

+#include <linux/delay.h> +#include <linux/dma-buf.h> +#include <linux/gpio/consumer.h> +#include <linux/module.h> +#include <linux/property.h> +#include <linux/spi/spi.h> +#include <video/mipi_display.h>

+#include <drm/drm_gem_framebuffer_helper.h> +#include <drm/tinydrm/mipi-dbi.h> +#include <drm/tinydrm/tinydrm-helpers.h>

+#define ST7735R_FRMCTR1 0xb1 +#define ST7735R_FRMCTR2 0xb2 +#define ST7735R_FRMCTR3 0xb3 +#define ST7735R_INVCTR 0xb4 +#define ST7735R_PWCTR1 0xc0 +#define ST7735R_PWCTR2 0xc1 +#define ST7735R_PWCTR3 0xc2 +#define ST7735R_PWCTR4 0xc3 +#define ST7735R_PWCTR5 0xc4 +#define ST7735R_VMCTR1 0xc5 +#define ST7735R_GAMCTRP1 0xe0 +#define ST7735R_GAMCTRN1 0xe1

+#define ST7735R_MY BIT(7) +#define ST7735R_MX BIT(6) +#define ST7735R_MV BIT(5)

+static void st7735r_pipe_enable(struct drm_simple_display_pipe *pipe,

• 		struct drm_crtc_state *crtc_state)
  

+{

• struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
• struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
• struct drm_framebuffer *fb = pipe->plane.fb;
• struct device *dev = tdev->drm->dev;
• int ret;
• u8 addr_mode;
• DRM_DEBUG_KMS("\n");
• mipi_dbi_hw_reset(mipi);
• ret = mipi_dbi_command(mipi, MIPI_DCS_SOFT_RESET);
• if (ret) {

• DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
  

• return;
  

• }
• msleep(150);
• mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
• msleep(500);
• mipi_dbi_command(mipi, ST7735R_FRMCTR1, 0x01, 0x2c, 0x2d);
• mipi_dbi_command(mipi, ST7735R_FRMCTR2, 0x01, 0x2c, 0x2d);
• mipi_dbi_command(mipi, ST7735R_FRMCTR3, 0x01, 0x2c, 0x2d, 0x01, 0x2c,

• 	 0x2d);
  

• mipi_dbi_command(mipi, ST7735R_INVCTR, 0x07);
• mipi_dbi_command(mipi, ST7735R_PWCTR1, 0xa2, 0x02, 0x84);
• mipi_dbi_command(mipi, ST7735R_PWCTR2, 0xc5);
• mipi_dbi_command(mipi, ST7735R_PWCTR3, 0x0a, 0x00);
• mipi_dbi_command(mipi, ST7735R_PWCTR4, 0x8a, 0x2a);
• mipi_dbi_command(mipi, ST7735R_PWCTR5, 0x8a, 0xee);
• mipi_dbi_command(mipi, ST7735R_VMCTR1, 0x0e);
• mipi_dbi_command(mipi, MIPI_DCS_EXIT_INVERT_MODE);
• switch (mipi->rotation) {
• default:

• addr_mode = ST7735R_MX | ST7735R_MY;
  

• break;
  

• case 90:

• addr_mode = ST7735R_MX | ST7735R_MV;
  

• break;
  

• case 180:

• addr_mode = 0;
  

• break;
  

• case 270:

• addr_mode = ST7735R_MY | ST7735R_MV;
  

• break;
  

• }
• mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
• mipi_dbi_command(mipi, MIPI_DCS_SET_PIXEL_FORMAT,

• 	 MIPI_DCS_PIXEL_FMT_16BIT);
  

• mipi_dbi_command(mipi, ST7735R_GAMCTRP1, 0x0f, 0x1a, 0x0f, 0x18, 0x2f,

• 	 0x28, 0x20, 0x22, 0x1f, 0x1b, 0x23, 0x37, 0x00, 0x07,
  

• 	 0x02, 0x10);
  

• mipi_dbi_command(mipi, ST7735R_GAMCTRN1, 0x0f, 0x1b, 0x0f, 0x17, 0x33,

• 	 0x2c, 0x29, 0x2e, 0x30, 0x30, 0x39, 0x3f, 0x00, 0x07,
  

• 	 0x03, 0x10);
  

• mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
• msleep(100);
• mipi_dbi_command(mipi, MIPI_DCS_ENTER_NORMAL_MODE);
• msleep(10);

Please use 20ms here to avoid warning:

-:168: WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt #168: FILE: drivers/gpu/drm/tinydrm/st7735r.c:107: +       msleep(10);

• mipi->enabled = true;
• if (fb)

• fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
  

• tinydrm_enable_backlight(mipi->backlight);

The previous lines can be replaced with:

mipi_dbi_pipe_enable(pipe, crtc_state);

I want us to use helpers as much as possible, and in this case the flushing will be reworked in the future so less places to touch when that happens.

+}

+static void st7735r_pipe_disable(struct drm_simple_display_pipe *pipe) +{

• struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
• struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);

Please use mipi_dbi_pipe_disable() here.

• DRM_DEBUG_KMS("\n");
• if (!mipi->enabled)

• return;
  

• tinydrm_disable_backlight(mipi->backlight);
• mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);

You turn off the panel, have you checked what it looks like if you don't turn off backlight (which is optional in this driver)?

On the displays I have tried this on, all pixels turn white when they're not driven, letting backlight through, giving an all white display. That's why I have that blanking code in mipi_dbi_pipe_disable() when we don't have backlight control and the reason I don't turn off the panel. The power savings of not driving the panel is negligible AFAICR.

If you don't need DISPLAY_OFF, you can just use mipi_dbi_pipe_disable() directly as the callback.

Noralf.

• mipi->enabled = false;

+}

+static const struct drm_simple_display_pipe_funcs st7735r_pipe_funcs = {

• .enable = st7735r_pipe_enable,
• .disable = st7735r_pipe_disable,
• .update = tinydrm_display_pipe_update,
• .prepare_fb = tinydrm_display_pipe_prepare_fb,

+};

+static const struct drm_display_mode st7735r_mode = {

• TINYDRM_MODE(128, 160, 28, 35),

+};

+DEFINE_DRM_GEM_CMA_FOPS(st7735r_fops);

+static struct drm_driver st7735r_driver = {

• .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |

• 		  DRIVER_ATOMIC,
  

• .fops = &st7735r_fops,
• TINYDRM_GEM_DRIVER_OPS,
• .lastclose = tinydrm_lastclose,
• .name = "st7735r",
• .desc = "Sitronix ST7735R",
• .date = "20171128",
• .major = 1,
• .minor = 0,

+};

+static const struct of_device_id st7735r_of_match[] = {

• { .compatible = "sitronix,st7735r-jd-t18003-t01" },
• {},

+}; +MODULE_DEVICE_TABLE(of, st7735r_of_match);

+static const struct spi_device_id st7735r_id[] = {

• { "st7735r-jd-t18003-t01", 0 },
• { },

+}; +MODULE_DEVICE_TABLE(spi, st7735r_id);

+static int st7735r_probe(struct spi_device *spi) +{

• struct device *dev = &spi->dev;
• struct mipi_dbi *mipi;
• struct gpio_desc *dc;
• u32 rotation = 0;
• int ret;
• mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
• if (!mipi)

• return -ENOMEM;
  

• mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
• if (IS_ERR(mipi->reset)) {

• DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
  

• return PTR_ERR(mipi->reset);
  

• }
• dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW);
• if (IS_ERR(dc)) {

• DRM_DEV_ERROR(dev, "Failed to get gpio 'dc'\n");
  

• return PTR_ERR(dc);
  

• }
• mipi->backlight = tinydrm_of_find_backlight(dev);
• if (IS_ERR(mipi->backlight))

• return PTR_ERR(mipi->backlight);
  

• device_property_read_u32(dev, "rotation", &rotation);
• ret = mipi_dbi_spi_init(spi, mipi, dc);
• if (ret)

• return ret;
  

• ret = mipi_dbi_init(&spi->dev, mipi, &st7735r_pipe_funcs,

• 	    &st7735r_driver, &st7735r_mode, rotation);
  

• if (ret)

• return ret;
  

• spi_set_drvdata(spi, mipi);
• return devm_tinydrm_register(&mipi->tinydrm);

+}

+static void st7735r_shutdown(struct spi_device *spi) +{

• struct mipi_dbi *mipi = spi_get_drvdata(spi);
• tinydrm_shutdown(&mipi->tinydrm);

+}

+static struct spi_driver st7735r_spi_driver = {

• .driver = {

• .name = "st7735r",
  

• .owner = THIS_MODULE,
  

• .of_match_table = st7735r_of_match,
  

• },
• .id_table = st7735r_id,
• .probe = st7735r_probe,
• .shutdown = st7735r_shutdown,

+}; +module_spi_driver(st7735r_spi_driver);

+MODULE_DESCRIPTION("Sitronix ST7735R DRM driver"); +MODULE_AUTHOR("David Lechner david@lechnology.com"); +MODULE_LICENSE("GPL");