[PATCH v6 5/5] drm/panel: Add support for the Raspberry Pi 7" Touchscreen.

Eric Anholt
2017-08-15T23:53:36Z

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 d84a031fae24..d6f1969b8a3b 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -73,6 +73,14 @@ 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 9f6610d08b00..bd17fac21c7b 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
obj-$(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_S6E8AA0) += panel-samsung-s6e8aa0.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