drm: Add an hx8367d tinydrm driver.

I want to sort out support for tinydrm in vc4, so I needed to get a
tinydrm-appropriate panel working and this is what I had on hand.
This is derived from a combination of ili9341.c from tinydrm and
fb_hx8357d.c from staging's fbtft.

v2: Write my own register defs from the spec to not need the header
from fbtft. Fix spi device string to enable module autoloading.
(Suggestions by Noralf)

Signed-off-by: Eric Anholt <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: Noralf Trønnes <[e-mail]> (v1)

MAINTAINERS

···
 F:	drivers/gpu/drm/tinydrm/ili9225.c
 F:	Documentation/devicetree/bindings/display/ilitek,ili9225.txt
 
+DRM DRIVER FOR HX8357D PANELS
+M:	Eric Anholt <[e-mail]>
+T:	git git://anongit.freedesktop.org/drm/drm-misc
+S:	Maintained
+F:	drivers/gpu/drm/tinydrm/hx8357d.c
+F:	Documentation/devicetree/bindings/display/himax,hx8357d.txt
+
 DRM DRIVER FOR INTEL I810 VIDEO CARDS
 S:	Orphan / Obsolete
 F:	drivers/gpu/drm/i810/

drivers/gpu/drm/tinydrm/Kconfig

···
 config TINYDRM_MIPI_DBI
 	tristate
 
+config TINYDRM_HX8357D
+	tristate "DRM support for HX8357D display panels"
+	depends on DRM_TINYDRM && SPI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select TINYDRM_MIPI_DBI
+	help
+	  DRM driver for the following HX8357D panels:
+	  * YX350HV15-T 3.5" 340x350 TFT (Adafruit 3.5")
+
+	  If M is selected the module will be called hx8357d.
+
 config TINYDRM_ILI9225
 	tristate "DRM support for ILI9225 display panels"
 	depends on DRM_TINYDRM && SPI

drivers/gpu/drm/tinydrm/Makefile

···
 obj-$(CONFIG_TINYDRM_MIPI_DBI)		+= mipi-dbi.o
 
 # Displays
+obj-$(CONFIG_TINYDRM_HX8357D)		+= hx8357d.o
 obj-$(CONFIG_TINYDRM_ILI9225)		+= ili9225.o
 obj-$(CONFIG_TINYDRM_ILI9341)		+= ili9341.o
 obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o

drivers/gpu/drm/tinydrm/hx8357d.c

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * DRM driver for the HX8357D LCD controller
+ *
+ * Copyright 2018 Broadcom
+ * Copyright 2018 David Lechner <[e-mail]>
+ * Copyright 2016 Noralf Trønnes
+ * Copyright (C) 2015 Adafruit Industries
+ * Copyright (C) 2013 Christian Vogelgsang
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_modeset_helper.h>
+#include <drm/tinydrm/mipi-dbi.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+#include <video/mipi_display.h>
+
+#define HX8357D_SETOSC 0xb0
+#define HX8357D_SETPOWER 0xb1
+#define HX8357D_SETRGB 0xb3
+#define HX8357D_SETCYC 0xb3
+#define HX8357D_SETCOM 0xb6
+#define HX8357D_SETEXTC 0xb9
+#define HX8357D_SETSTBA 0xc0
+#define HX8357D_SETPANEL 0xcc
+#define HX8357D_SETGAMMA 0xe0
+
+#define HX8357D_MADCTL_MY  0x80
+#define HX8357D_MADCTL_MX  0x40
+#define HX8357D_MADCTL_MV  0x20
+#define HX8357D_MADCTL_ML  0x10
+#define HX8357D_MADCTL_RGB 0x00
+#define HX8357D_MADCTL_BGR 0x08
+#define HX8357D_MADCTL_MH  0x04
+
+static void yx240qv29_enable(struct drm_simple_display_pipe *pipe,
+			     struct drm_crtc_state *crtc_state,
+			     struct drm_plane_state *plane_state)
+{
+	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
+	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+	u8 addr_mode;
+	int ret;
+
+	DRM_DEBUG_KMS("\n");
+
+	ret = mipi_dbi_poweron_conditional_reset(mipi);
+	if (ret < 0)
+		return;
+	if (ret == 1)
+		goto out_enable;
+
+	/* setextc */
+	mipi_dbi_command(mipi, HX8357D_SETEXTC, 0xFF, 0x83, 0x57);
+	msleep(150);
+
+	/* setRGB which also enables SDO */
+	mipi_dbi_command(mipi, HX8357D_SETRGB, 0x00, 0x00, 0x06, 0x06);
+
+	/* -1.52V */
+	mipi_dbi_command(mipi, HX8357D_SETCOM, 0x25);
+
+	/* Normal mode 70Hz, Idle mode 55 Hz */
+	mipi_dbi_command(mipi, HX8357D_SETOSC, 0x68);
+
+	/* Set Panel - BGR, Gate direction swapped */
+	mipi_dbi_command(mipi, HX8357D_SETPANEL, 0x05);
+
+	mipi_dbi_command(mipi, HX8357D_SETPOWER,
+			 0x00,  /* Not deep standby */
+			 0x15,  /* BT */
+			 0x1C,  /* VSPR */
+			 0x1C,  /* VSNR */
+			 0x83,  /* AP */
+			 0xAA);  /* FS */
+
+	mipi_dbi_command(mipi, HX8357D_SETSTBA,
+			 0x50,  /* OPON normal */
+			 0x50,  /* OPON idle */
+			 0x01,  /* STBA */
+			 0x3C,  /* STBA */
+			 0x1E,  /* STBA */
+			 0x08);  /* GEN */
+
+	mipi_dbi_command(mipi, HX8357D_SETCYC,
+			 0x02,  /* NW 0x02 */
+			 0x40,  /* RTN */
+			 0x00,  /* DIV */
+			 0x2A,  /* DUM */
+			 0x2A,  /* DUM */
+			 0x0D,  /* GDON */
+			 0x78);  /* GDOFF */
+
+	mipi_dbi_command(mipi, HX8357D_SETGAMMA,
+			 0x02,
+			 0x0A,
+			 0x11,
+			 0x1d,
+			 0x23,
+			 0x35,
+			 0x41,
+			 0x4b,
+			 0x4b,
+			 0x42,
+			 0x3A,
+			 0x27,
+			 0x1B,
+			 0x08,
+			 0x09,
+			 0x03,
+			 0x02,
+			 0x0A,
+			 0x11,
+			 0x1d,
+			 0x23,
+			 0x35,
+			 0x41,
+			 0x4b,
+			 0x4b,
+			 0x42,
+			 0x3A,
+			 0x27,
+			 0x1B,
+			 0x08,
+			 0x09,
+			 0x03,
+			 0x00,
+			 0x01);
+
+	/* 16 bit */
+	mipi_dbi_command(mipi, MIPI_DCS_SET_PIXEL_FORMAT,
+			 MIPI_DCS_PIXEL_FMT_16BIT);
+
+	/* TE off */
+	mipi_dbi_command(mipi, MIPI_DCS_SET_TEAR_ON, 0x00);
+
+	/* tear line */
+	mipi_dbi_command(mipi, MIPI_DCS_SET_TEAR_SCANLINE, 0x00, 0x02);
+
+	/* Exit Sleep */
+	mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
+	msleep(150);
+
+	/* display on */
+	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
+	usleep_range(5000, 7000);
+
+out_enable:
+	switch (mipi->rotation) {
+	default:
+		addr_mode = HX8357D_MADCTL_MX | HX8357D_MADCTL_MY;
+		break;
+	case 90:
+		addr_mode = HX8357D_MADCTL_MV | HX8357D_MADCTL_MY;
+		break;
+	case 180:
+		addr_mode = 0;
+		break;
+	case 270:
+		addr_mode = HX8357D_MADCTL_MV | HX8357D_MADCTL_MX;
+		break;
+	}
+	mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
+	mipi_dbi_enable_flush(mipi, crtc_state, plane_state);
+}
+
+static const struct drm_simple_display_pipe_funcs hx8357d_pipe_funcs = {
+	.enable = yx240qv29_enable,
+	.disable = mipi_dbi_pipe_disable,
+	.update = tinydrm_display_pipe_update,
+	.prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
+};
+
+static const struct drm_display_mode yx350hv15_mode = {
+	TINYDRM_MODE(320, 480, 60, 75),
+};
+
+DEFINE_DRM_GEM_CMA_FOPS(hx8357d_fops);
+
+static struct drm_driver hx8357d_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME | DRIVER_ATOMIC,
+	.fops			= &hx8357d_fops,
+	TINYDRM_GEM_DRIVER_OPS,
+	.debugfs_init		= mipi_dbi_debugfs_init,
+	.name			= "hx8357d",
+	.desc			= "HX8357D",
+	.date			= "20181023",
+	.major			= 1,
+	.minor			= 0,
+};
+
+static const struct of_device_id hx8357d_of_match[] = {
+	{ .compatible = "adafruit,yx350hv15" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, hx8357d_of_match);
+
+static const struct spi_device_id hx8357d_id[] = {
+	{ "yx350hv15", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, hx8357d_id);
+
+static int hx8357d_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;
+
+	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 = devm_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, &hx8357d_pipe_funcs,
+			    &hx8357d_driver, &yx350hv15_mode, rotation);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, mipi);
+
+	return devm_tinydrm_register(&mipi->tinydrm);
+}
+
+static void hx8357d_shutdown(struct spi_device *spi)
+{
+	struct mipi_dbi *mipi = spi_get_drvdata(spi);
+
+	tinydrm_shutdown(&mipi->tinydrm);
+}
+
+static struct spi_driver hx8357d_spi_driver = {
+	.driver = {
+		.name = "hx8357d",
+		.of_match_table = hx8357d_of_match,
+	},
+	.id_table = hx8357d_id,
+	.probe = hx8357d_probe,
+	.shutdown = hx8357d_shutdown,
+};
+module_spi_driver(hx8357d_spi_driver);
+
+MODULE_DESCRIPTION("HX8357D DRM driver");
+MODULE_AUTHOR("Eric Anholt <[e-mail]>");
+MODULE_LICENSE("GPL");