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linux/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
Eric Anholt 2f733d6194 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: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20170927193654.12609-4-eric@anholt.net
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Acked-by: Thierry Reding <treding@nvidia.com>
2017-10-06 12:10:16 -07:00

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/*
* 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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