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SubjectRe: [PATCH v6 3/3] drm/panel: Add support for the Raspberry Pi 7" Touchscreen.
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On 09/28/2017 01:06 AM, Eric Anholt wrote:
> 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.

Reviewed-by: Archit Taneja <architt@codeaurora.org>

>
> 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");
>

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