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    Subject[PATCH v6 3/3] drm/panel: Add support for the Raspberry Pi 7" Touchscreen.
    Date
    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.

    Signed-off-by: Eric Anholt <eric@anholt.net>
    ---
    drivers/gpu/drm/panel/Kconfig | 8 +
    drivers/gpu/drm/panel/Makefile | 1 +
    .../gpu/drm/panel/panel-raspberrypi-touchscreen.c | 517 +++++++++++++++++++++
    3 files changed, 526 insertions(+)
    create mode 100644 drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c

    diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
    index 718d8ce15b1f..726f3fb3312d 100644
    --- a/drivers/gpu/drm/panel/Kconfig
    +++ b/drivers/gpu/drm/panel/Kconfig
    @@ -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
    diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
    index c8483fdd5b9b..77ede3467324 100644
    --- a/drivers/gpu/drm/panel/Makefile
    +++ b/drivers/gpu/drm/panel/Makefile
    @@ -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
    diff --git a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
    new file mode 100644
    index 000000000000..4237a0cbcdcc
    --- /dev/null
    +++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
    @@ -0,0 +1,517 @@
    +/*
    + * 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,
    +};
    +
    +/* We only turn the PWM on or off, without varying values. */
    +#define RPI_TOUCHSCREEN_MAX_BRIGHTNESS 1
    +
    +/* 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");
    --
    2.14.1
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      Last update: 2017-09-27 21:37    [W:32.689 / U:0.052 seconds]
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