drm/panel: Add support for the Raspberry Pi 7" Touchscreen.
authorEric Anholt <eric@anholt.net>
Wed, 27 Sep 2017 19:36:54 +0000 (12:36 -0700)
committerEric Anholt <eric@anholt.net>
Fri, 6 Oct 2017 19:10:16 +0000 (12:10 -0700)
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>
drivers/gpu/drm/panel/Kconfig
drivers/gpu/drm/panel/Makefile
drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c [new file with mode: 0644]

index 718d8ce..726f3fb 100644 (file)
@@ -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
index c8483fd..77ede34 100644 (file)
@@ -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 (file)
index 0000000..890fd6f
--- /dev/null
@@ -0,0 +1,514 @@
+/*
+ * 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");