Commit 2f733d61 authored by Eric Anholt's avatar Eric Anholt
Browse files

drm/panel: Add support for the Raspberry Pi 7" Touchscreen. 



This driver communicates with the Atmel microcontroller for sequencing
the poweron of the TC358762 DSI-DPI bridge and controlling the
backlight PWM.

v2: Set the same default orientation as the closed source firmware
    used, which is the best for viewing angle.
v3: Rewrite as an i2c client driver after bridge driver rejection.
v4: Finish probe without the DSI host, using the new delayed
    registration, and attach to the host during mipi_dsi_driver probe.
v5: Rework to drop the "probe without DSI host" mode again, now that
    vc4 will create the host early on.
v6: Drop unused brightness #define (noticed by Thierry)

Signed-off-by: default avatarEric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20170927193654.12609-4-eric@anholt.net


Reviewed-by: default avatarArchit Taneja <architt@codeaurora.org>
Acked-by: default avatarThierry Reding <treding@nvidia.com>
parent 407b0b1e

drivers/gpu/drm/panel/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -82,6 +82,14 @@ config DRM_PANEL_PANASONIC_VVX10F034N00 
	  WUXGA (1920x1200) Novatek NT1397-based DSI panel as found in some

	  Xperia Z2 tablets



config DRM_PANEL_RASPBERRYPI_TOUCHSCREEN

	tristate "Raspberry Pi 7-inch touchscreen panel"

	depends on DRM_MIPI_DSI

	help

	  Say Y here if you want to enable support for the Raspberry

	  Pi 7" Touchscreen.  To compile this driver as a module,

	  choose M here.



config DRM_PANEL_SAMSUNG_S6E3HA2

	tristate "Samsung S6E3HA2 DSI video mode panel"

	depends on OF

drivers/gpu/drm/panel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o 
obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o

obj-$(CONFIG_DRM_PANEL_ORISETECH_OTM8009A) += panel-orisetech-otm8009a.o

obj-$(CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00) += panel-panasonic-vvx10f034n00.o

obj-$(CONFIG_DRM_PANEL_RASPBERRYPI_TOUCHSCREEN) += panel-raspberrypi-touchscreen.o

obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o

obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E3HA2) += panel-samsung-s6e3ha2.o

obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o

drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c

0 → 100644
+514 −0
Original line number Diff line number Diff line 
/*

 * Copyright © 2016-2017 Broadcom

 *

 * 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.

 *

 * Portions of this file (derived from panel-simple.c) are:

 *

 * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sub license,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the

 * next paragraph) shall be included in all copies or substantial portions

 * of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */



/**

 * Raspberry Pi 7" touchscreen panel driver.

 *

 * The 7" touchscreen consists of a DPI LCD panel, a Toshiba

 * TC358762XBG DSI-DPI bridge, and an I2C-connected Atmel ATTINY88-MUR

 * controlling power management, the LCD PWM, and initial register

 * setup of the Tohsiba.

 *

 * This driver controls the TC358762 and ATTINY88, presenting a DSI

 * device with a drm_panel.

 */



#include <linux/delay.h>

#include <linux/err.h>

#include <linux/fb.h>

#include <linux/gpio.h>

#include <linux/gpio/consumer.h>

#include <linux/i2c.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_graph.h>

#include <linux/pm.h>



#include <drm/drm_panel.h>

#include <drm/drmP.h>

#include <drm/drm_crtc.h>

#include <drm/drm_mipi_dsi.h>

#include <drm/drm_panel.h>



#define RPI_DSI_DRIVER_NAME "rpi-ts-dsi"



/* I2C registers of the Atmel microcontroller. */

enum REG_ADDR {

	REG_ID = 0x80,

	REG_PORTA, /* BIT(2) for horizontal flip, BIT(3) for vertical flip */

	REG_PORTB,

	REG_PORTC,

	REG_PORTD,

	REG_POWERON,

	REG_PWM,

	REG_DDRA,

	REG_DDRB,

	REG_DDRC,

	REG_DDRD,

	REG_TEST,

	REG_WR_ADDRL,

	REG_WR_ADDRH,

	REG_READH,

	REG_READL,

	REG_WRITEH,

	REG_WRITEL,

	REG_ID2,

};



/* DSI D-PHY Layer Registers */

#define D0W_DPHYCONTTX		0x0004

#define CLW_DPHYCONTRX		0x0020

#define D0W_DPHYCONTRX		0x0024

#define D1W_DPHYCONTRX		0x0028

#define COM_DPHYCONTRX		0x0038

#define CLW_CNTRL		0x0040

#define D0W_CNTRL		0x0044

#define D1W_CNTRL		0x0048

#define DFTMODE_CNTRL		0x0054



/* DSI PPI Layer Registers */

#define PPI_STARTPPI		0x0104

#define PPI_BUSYPPI		0x0108

#define PPI_LINEINITCNT		0x0110

#define PPI_LPTXTIMECNT		0x0114

#define PPI_CLS_ATMR		0x0140

#define PPI_D0S_ATMR		0x0144

#define PPI_D1S_ATMR		0x0148

#define PPI_D0S_CLRSIPOCOUNT	0x0164

#define PPI_D1S_CLRSIPOCOUNT	0x0168

#define CLS_PRE			0x0180

#define D0S_PRE			0x0184

#define D1S_PRE			0x0188

#define CLS_PREP		0x01A0

#define D0S_PREP		0x01A4

#define D1S_PREP		0x01A8

#define CLS_ZERO		0x01C0

#define D0S_ZERO		0x01C4

#define D1S_ZERO		0x01C8

#define PPI_CLRFLG		0x01E0

#define PPI_CLRSIPO		0x01E4

#define HSTIMEOUT		0x01F0

#define HSTIMEOUTENABLE		0x01F4



/* DSI Protocol Layer Registers */

#define DSI_STARTDSI		0x0204

#define DSI_BUSYDSI		0x0208

#define DSI_LANEENABLE		0x0210

# define DSI_LANEENABLE_CLOCK		BIT(0)

# define DSI_LANEENABLE_D0		BIT(1)

# define DSI_LANEENABLE_D1		BIT(2)



#define DSI_LANESTATUS0		0x0214

#define DSI_LANESTATUS1		0x0218

#define DSI_INTSTATUS		0x0220

#define DSI_INTMASK		0x0224

#define DSI_INTCLR		0x0228

#define DSI_LPTXTO		0x0230

#define DSI_MODE		0x0260

#define DSI_PAYLOAD0		0x0268

#define DSI_PAYLOAD1		0x026C

#define DSI_SHORTPKTDAT		0x0270

#define DSI_SHORTPKTREQ		0x0274

#define DSI_BTASTA		0x0278

#define DSI_BTACLR		0x027C



/* DSI General Registers */

#define DSIERRCNT		0x0300

#define DSISIGMOD		0x0304



/* DSI Application Layer Registers */

#define APLCTRL			0x0400

#define APLSTAT			0x0404

#define APLERR			0x0408

#define PWRMOD			0x040C

#define RDPKTLN			0x0410

#define PXLFMT			0x0414

#define MEMWRCMD		0x0418



/* LCDC/DPI Host Registers */

#define LCDCTRL			0x0420

#define HSR			0x0424

#define HDISPR			0x0428

#define VSR			0x042C

#define VDISPR			0x0430

#define VFUEN			0x0434



/* DBI-B Host Registers */

#define DBIBCTRL		0x0440



/* SPI Master Registers */

#define SPICMR			0x0450

#define SPITCR			0x0454



/* System Controller Registers */

#define SYSSTAT			0x0460

#define SYSCTRL			0x0464

#define SYSPLL1			0x0468

#define SYSPLL2			0x046C

#define SYSPLL3			0x0470

#define SYSPMCTRL		0x047C



/* GPIO Registers */

#define GPIOC			0x0480

#define GPIOO			0x0484

#define GPIOI			0x0488



/* I2C Registers */

#define I2CCLKCTRL		0x0490



/* Chip/Rev Registers */

#define IDREG			0x04A0



/* Debug Registers */

#define WCMDQUEUE		0x0500

#define RCMDQUEUE		0x0504



struct rpi_touchscreen {

	struct drm_panel base;

	struct mipi_dsi_device *dsi;

	struct i2c_client *i2c;

};



static const struct drm_display_mode rpi_touchscreen_modes[] = {

	{

		/* Modeline comes from the Raspberry Pi firmware, with HFP=1

		 * plugged in and clock re-computed from that.

		 */

		.clock = 25979400 / 1000,

		.hdisplay = 800,

		.hsync_start = 800 + 1,

		.hsync_end = 800 + 1 + 2,

		.htotal = 800 + 1 + 2 + 46,

		.vdisplay = 480,

		.vsync_start = 480 + 7,

		.vsync_end = 480 + 7 + 2,

		.vtotal = 480 + 7 + 2 + 21,

		.vrefresh = 60,

	},

};



static struct rpi_touchscreen *panel_to_ts(struct drm_panel *panel)

{

	return container_of(panel, struct rpi_touchscreen, base);

}



static u8 rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)

{

	return i2c_smbus_read_byte_data(ts->i2c, reg);

}



static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,

				      u8 reg, u8 val)

{

	int ret;



	ret = i2c_smbus_write_byte_data(ts->i2c, reg, val);

	if (ret)

		dev_err(&ts->dsi->dev, "I2C write failed: %d\n", ret);

}



static int rpi_touchscreen_write(struct rpi_touchscreen *ts, u16 reg, u32 val)

{

#if 0

	/* The firmware uses LP DSI transactions like this to bring up

	 * the hardware, which should be faster than using I2C to then

	 * pass to the Toshiba.  However, I was unable to get it to

	 * work.

	 */

	u8 msg[] = {

		reg,

		reg >> 8,

		val,

		val >> 8,

		val >> 16,

		val >> 24,

	};



	mipi_dsi_dcs_write_buffer(ts->dsi, msg, sizeof(msg));

#else

	rpi_touchscreen_i2c_write(ts, REG_WR_ADDRH, reg >> 8);

	rpi_touchscreen_i2c_write(ts, REG_WR_ADDRL, reg);

	rpi_touchscreen_i2c_write(ts, REG_WRITEH, val >> 8);

	rpi_touchscreen_i2c_write(ts, REG_WRITEL, val);

#endif



	return 0;

}



static int rpi_touchscreen_disable(struct drm_panel *panel)

{

	struct rpi_touchscreen *ts = panel_to_ts(panel);



	rpi_touchscreen_i2c_write(ts, REG_PWM, 0);



	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);

	udelay(1);



	return 0;

}



static int rpi_touchscreen_noop(struct drm_panel *panel)

{

	return 0;

}



static int rpi_touchscreen_enable(struct drm_panel *panel)

{

	struct rpi_touchscreen *ts = panel_to_ts(panel);

	int i;



	rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);

	/* Wait for nPWRDWN to go low to indicate poweron is done. */

	for (i = 0; i < 100; i++) {

		if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)

			break;

	}



	rpi_touchscreen_write(ts, DSI_LANEENABLE,

			      DSI_LANEENABLE_CLOCK |

			      DSI_LANEENABLE_D0);

	rpi_touchscreen_write(ts, PPI_D0S_CLRSIPOCOUNT, 0x05);

	rpi_touchscreen_write(ts, PPI_D1S_CLRSIPOCOUNT, 0x05);

	rpi_touchscreen_write(ts, PPI_D0S_ATMR, 0x00);

	rpi_touchscreen_write(ts, PPI_D1S_ATMR, 0x00);

	rpi_touchscreen_write(ts, PPI_LPTXTIMECNT, 0x03);



	rpi_touchscreen_write(ts, SPICMR, 0x00);

	rpi_touchscreen_write(ts, LCDCTRL, 0x00100150);

	rpi_touchscreen_write(ts, SYSCTRL, 0x040f);

	msleep(100);



	rpi_touchscreen_write(ts, PPI_STARTPPI, 0x01);

	rpi_touchscreen_write(ts, DSI_STARTDSI, 0x01);

	msleep(100);



	/* Turn on the backlight. */

	rpi_touchscreen_i2c_write(ts, REG_PWM, 255);



	/* Default to the same orientation as the closed source

	 * firmware used for the panel.  Runtime rotation

	 * configuration will be supported using VC4's plane

	 * orientation bits.

	 */

	rpi_touchscreen_i2c_write(ts, REG_PORTA, BIT(2));



	return 0;

}



static int rpi_touchscreen_get_modes(struct drm_panel *panel)

{

	struct drm_connector *connector = panel->connector;

	struct drm_device *drm = panel->drm;

	unsigned int i, num = 0;

	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;



	for (i = 0; i < ARRAY_SIZE(rpi_touchscreen_modes); i++) {

		const struct drm_display_mode *m = &rpi_touchscreen_modes[i];

		struct drm_display_mode *mode;



		mode = drm_mode_duplicate(drm, m);

		if (!mode) {

			dev_err(drm->dev, "failed to add mode %ux%u@%u\n",

				m->hdisplay, m->vdisplay, m->vrefresh);

			continue;

		}



		mode->type |= DRM_MODE_TYPE_DRIVER;



		if (i == 0)

			mode->type |= DRM_MODE_TYPE_PREFERRED;



		drm_mode_set_name(mode);



		drm_mode_probed_add(connector, mode);

		num++;

	}



	connector->display_info.bpc = 8;

	connector->display_info.width_mm = 154;

	connector->display_info.height_mm = 86;

	drm_display_info_set_bus_formats(&connector->display_info,

					 &bus_format, 1);



	return num;

}



static const struct drm_panel_funcs rpi_touchscreen_funcs = {

	.disable = rpi_touchscreen_disable,

	.unprepare = rpi_touchscreen_noop,

	.prepare = rpi_touchscreen_noop,

	.enable = rpi_touchscreen_enable,

	.get_modes = rpi_touchscreen_get_modes,

};



static int rpi_touchscreen_probe(struct i2c_client *i2c,

				 const struct i2c_device_id *id)

{

	struct device *dev = &i2c->dev;

	struct rpi_touchscreen *ts;

	struct device_node *endpoint, *dsi_host_node;

	struct mipi_dsi_host *host;

	int ret, ver;

	struct mipi_dsi_device_info info = {

		.type = RPI_DSI_DRIVER_NAME,

		.channel = 0,

		.node = NULL,

	};



	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);

	if (!ts)

		return -ENOMEM;



	i2c_set_clientdata(i2c, ts);



	ts->i2c = i2c;



	ver = rpi_touchscreen_i2c_read(ts, REG_ID);

	if (ver < 0) {

		dev_err(dev, "Atmel I2C read failed: %d\n", ver);

		return -ENODEV;

	}



	switch (ver) {

	case 0xde: /* ver 1 */

	case 0xc3: /* ver 2 */

		break;

	default:

		dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);

		return -ENODEV;

	}



	/* Turn off at boot, so we can cleanly sequence powering on. */

	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);



	/* Look up the DSI host.  It needs to probe before we do. */

	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);

	dsi_host_node = of_graph_get_remote_port_parent(endpoint);

	host = of_find_mipi_dsi_host_by_node(dsi_host_node);

	of_node_put(dsi_host_node);

	if (!host) {

		of_node_put(endpoint);

		return -EPROBE_DEFER;

	}



	info.node = of_graph_get_remote_port(endpoint);

	of_node_put(endpoint);



	ts->dsi = mipi_dsi_device_register_full(host, &info);

	if (IS_ERR(ts->dsi)) {

		dev_err(dev, "DSI device registration failed: %ld\n",

			PTR_ERR(ts->dsi));

		return PTR_ERR(ts->dsi);

	}



	ts->base.dev = dev;

	ts->base.funcs = &rpi_touchscreen_funcs;



	/* This appears last, as it's what will unblock the DSI host

	 * driver's component bind function.

	 */

	ret = drm_panel_add(&ts->base);

	if (ret)

		return ret;



	return 0;

}



static int rpi_touchscreen_remove(struct i2c_client *i2c)

{

	struct rpi_touchscreen *ts = i2c_get_clientdata(i2c);



	mipi_dsi_detach(ts->dsi);



	drm_panel_remove(&ts->base);



	mipi_dsi_device_unregister(ts->dsi);

	kfree(ts->dsi);



	return 0;

}



static int rpi_touchscreen_dsi_probe(struct mipi_dsi_device *dsi)

{

	int ret;



	dsi->mode_flags = (MIPI_DSI_MODE_VIDEO |

			   MIPI_DSI_MODE_VIDEO_SYNC_PULSE |

			   MIPI_DSI_MODE_LPM);

	dsi->format = MIPI_DSI_FMT_RGB888;

	dsi->lanes = 1;



	ret = mipi_dsi_attach(dsi);



	if (ret)

		dev_err(&dsi->dev, "failed to attach dsi to host: %d\n", ret);



	return ret;

}



static struct mipi_dsi_driver rpi_touchscreen_dsi_driver = {

	.driver.name = RPI_DSI_DRIVER_NAME,

	.probe = rpi_touchscreen_dsi_probe,

};



static const struct of_device_id rpi_touchscreen_of_ids[] = {

	{ .compatible = "raspberrypi,7inch-touchscreen-panel" },

	{ } /* sentinel */

};

MODULE_DEVICE_TABLE(of, rpi_touchscreen_of_ids);



static struct i2c_driver rpi_touchscreen_driver = {

	.driver = {

		.name = "rpi_touchscreen",

		.of_match_table = rpi_touchscreen_of_ids,

	},

	.probe = rpi_touchscreen_probe,

	.remove = rpi_touchscreen_remove,

};



static int __init rpi_touchscreen_init(void)

{

	mipi_dsi_driver_register(&rpi_touchscreen_dsi_driver);

	return i2c_add_driver(&rpi_touchscreen_driver);

}

module_init(rpi_touchscreen_init);



static void __exit rpi_touchscreen_exit(void)

{

	i2c_del_driver(&rpi_touchscreen_driver);

	mipi_dsi_driver_unregister(&rpi_touchscreen_dsi_driver);

}

module_exit(rpi_touchscreen_exit);



MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");

MODULE_DESCRIPTION("Raspberry Pi 7-inch touchscreen driver");

MODULE_LICENSE("GPL v2");

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