[PATCH v6 0/3] RPi touchscreen panel resend.

[PATCH v6 0/3] RPi touchscreen panel resend.

[Eric Anholt]

I pushed a couple of the patches from the series, so here's what's
left.  I figured it was time for a resend at this point.

Eric Anholt (3):
  drm/vc4: Move the DSI clock divider workaround closer to the clock
    call.
  dt-bindings: Document the Raspberry Pi Touchscreen nodes.
  drm/panel: Add support for the Raspberry Pi 7" Touchscreen.

 .../panel/raspberrypi,7inch-touchscreen.txt        |  49 ++
 drivers/gpu/drm/panel/Kconfig                      |   8 +
 drivers/gpu/drm/panel/Makefile                     |   1 +
 .../gpu/drm/panel/panel-raspberrypi-touchscreen.c  | 517 +++++++++++++++++++++
 drivers/gpu/drm/vc4/vc4_dsi.c                      |  12 +-
 5 files changed, 581 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touchscreen.txt
 create mode 100644 drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c

-- 
2.14.1

[PATCH v6 1/3] drm/vc4: Move the DSI clock divider workaround closer to the clock call.

[Eric Anholt]

We want the adjusted_mode->clock to be the actual clock we're
expecting to program, so that consumers see the right values for clock
and vrefresh.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_dsi.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
index 925c726ac694..554605af344e 100644
--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -859,11 +859,7 @@ static bool vc4_dsi_encoder_mode_fixup(struct drm_encoder *encoder,
 	pll_clock = parent_rate / divider;
 	pixel_clock_hz = pll_clock / dsi->divider;
 
-	/* Round up the clk_set_rate() request slightly, since
-	 * PLLD_DSI1 is an integer divider and its rate selection will
-	 * never round up.
-	 */
-	adjusted_mode->clock = pixel_clock_hz / 1000 + 1;
+	adjusted_mode->clock = pixel_clock_hz / 1000;
 
 	/* Given the new pixel clock, adjust HFP to keep vrefresh the same. */
 	adjusted_mode->htotal = adjusted_mode->clock * mode->htotal /
@@ -901,7 +897,11 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder)
 		vc4_dsi_dump_regs(dsi);
 	}
 
-	phy_clock = pixel_clock_hz * dsi->divider;
+	/* Round up the clk_set_rate() request slightly, since
+	 * PLLD_DSI1 is an integer divider and its rate selection will
+	 * never round up.
+	 */
+	phy_clock = (pixel_clock_hz + 1000) * dsi->divider;
 	ret = clk_set_rate(dsi->pll_phy_clock, phy_clock);
 	if (ret) {
 		dev_err(&dsi->pdev->dev,
-- 
2.14.1

Re: [PATCH v6 1/3] drm/vc4: Move the DSI clock divider workaround closer to the clock call.

[Thierry Reding]

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On Wed, Sep 27, 2017 at 12:36:52PM -0700, Eric Anholt wrote:
> We want the adjusted_mode->clock to be the actual clock we're
> expecting to program, so that consumers see the right values for clock
> and vrefresh.
> 
> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
>  drivers/gpu/drm/vc4/vc4_dsi.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)

Do you want me to apply this to drm-misc-next along with the touchscreen
panel driver?

Thierry

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Re: [PATCH v6 1/3] drm/vc4: Move the DSI clock divider workaround closer to the clock call.

[Eric Anholt]

[-- Attachment #1: Type: text/plain, Size: 766 bytes --]

Thierry Reding <thierry.reding@gmail.com> writes:

> [ Unknown signature status ]
> On Wed, Sep 27, 2017 at 12:36:52PM -0700, Eric Anholt wrote:
>> We want the adjusted_mode->clock to be the actual clock we're
>> expecting to program, so that consumers see the right values for clock
>> and vrefresh.
>> 
>> Signed-off-by: Eric Anholt <eric@anholt.net>
>> ---
>>  drivers/gpu/drm/vc4/vc4_dsi.c | 12 ++++++------
>>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> Do you want me to apply this to drm-misc-next along with the touchscreen
> panel driver?

drm-misc-next procedure trends toward the submitter applies the patch
once they get review, if they have the commit rights.  However, I'm
happy either way as long as I can get the code in.

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[PATCH v6 2/3] dt-bindings: Document the Raspberry Pi Touchscreen nodes.

[Eric Anholt]

This doesn't yet cover input, but the driver does get the display
working when the firmware is disabled from talking to our I2C lines.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../panel/raspberrypi,7inch-touchscreen.txt        | 49 ++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touchscreen.txt

diff --git a/Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touchscreen.txt b/Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touchscreen.txt
new file mode 100644
index 000000000000..e9e19c059260
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touchscreen.txt
@@ -0,0 +1,49 @@
+This binding covers the official 7" (800x480) Raspberry Pi touchscreen
+panel.
+
+This DSI panel contains:
+
+- TC358762 DSI->DPI bridge
+- Atmel microcontroller on I2C for power sequencing the DSI bridge and
+  controlling backlight
+- Touchscreen controller on I2C for touch input
+
+and this binding covers the DSI display parts but not its touch input.
+
+Required properties:
+- compatible:	Must be "raspberrypi,7inch-touchscreen-panel"
+- reg:		Must be "45"
+- port:		See panel-common.txt
+
+Example:
+
+dsi1: dsi@7e700000 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	<...>
+
+	port {
+		dsi_out_port: endpoint {
+			remote-endpoint = <&panel_dsi_port>;
+		};
+	};
+};
+
+i2c_dsi: i2c {
+	compatible = "i2c-gpio";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	gpios = <&gpio 28 0
+		 &gpio 29 0>;
+
+	lcd@45 {
+		compatible = "raspberrypi,7inch-touchscreen-panel";
+		reg = <0x45>;
+
+		port {
+			panel_dsi_port: endpoint {
+				remote-endpoint = <&dsi_out_port>;
+			};
+		};
+	};
+};
-- 
2.14.1

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

[Eric Anholt]

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

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

[Archit Taneja]

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");
> 

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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

[Thierry Reding]

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On Wed, Sep 27, 2017 at 12:36:54PM -0700, Eric Anholt wrote:
[...]
> diff --git a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
[...]
> +/* We only turn the PWM on or off, without varying values. */
> +#define RPI_TOUCHSCREEN_MAX_BRIGHTNESS 1

This seems to be unused now.

Otherwise:

Acked-by: Thierry Reding <treding@nvidia.com>

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