[PATCH v21 0/4] Add support for the silergy,sy7636a

[PATCH v21 0/4] Add support for the silergy,sy7636a

[Alistair Francis]

v21:
 - Rebase on master
v20:
 - Remove merged patches
 - Fixup Kconfig selection based on previous discussions
v19:
 - Rebase on linux-next
v18:
 - Rebase
v17:
 - Rebase and fix build issues
v16:
 - Improve vdd regulator comments
v15:
 - Address comments on the patches
v14:
 - Merge the thermal driver and hwmon
v13:
 - Address comments on thermal driver
 - Rebase on master (without other patches)
v12:
 - Rebase
v11:
 - Address comments on hwmon
 - Improve "mfd: simple-mfd-i2c: Add a Kconfig name" commit message
v10:
 - Use dev_get_regmap() instead of dev_get_drvdata()
v9:
 - Convert to use the simple-mfd-i2c instead

Alistair Francis (4):
  mfd: silergy,sy7636a: Add config option
  ARM: imx_v6_v7_defconfig: Enable silergy,sy7636a
  ARM: dts: imx7d-remarkable2: Enable silergy,sy7636a
  ARM: dts: imx7d-remarkable2: Enable lcdif

 arch/arm/boot/dts/imx7d-remarkable2.dts | 136 ++++++++++++++++++++++++
 arch/arm/configs/imx_v6_v7_defconfig    |   3 +
 drivers/hwmon/Kconfig                   |   1 +
 drivers/mfd/Kconfig                     |  12 ++-
 drivers/regulator/Kconfig               |   1 +
 5 files changed, 152 insertions(+), 1 deletion(-)

-- 
2.35.3

[PATCH v21 1/4] mfd: silergy,sy7636a: Add config option

[Alistair Francis]

Add a specific MFD_SY7636A config option.

As part of this change we can use MFD_SY7636A as a dependency for all
SY7636a components and also remove the name from MFD_SIMPLE_MFD_I2C as
it no longer needs to be selectable.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/Kconfig     |  1 +
 drivers/mfd/Kconfig       | 12 +++++++++++-
 drivers/regulator/Kconfig |  1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 590d3d550acb..a3a3b73b0a87 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1740,6 +1740,7 @@ config SENSORS_SIS5595
 
 config SENSORS_SY7636A
 	tristate "Silergy SY7636A"
+	depends on MFD_SY7636A
 	help
 	  If you say yes here you get support for the thermistor readout of
 	  the Silergy SY7636A PMIC.
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 3b59456f5545..c47cb755757b 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1095,6 +1095,16 @@ config MFD_SPMI_PMIC
 	  Say M here if you want to include support for the SPMI PMIC
 	  series as a module.  The module will be called "qcom-spmi-pmic".
 
+config MFD_SY7636A
+	tristate "Silergy SY7636A voltage regulator"
+	depends on I2C
+	select MFD_SIMPLE_MFD_I2C
+	help
+	  Enable support for Silergy SY7636A voltage regulator.
+
+	  To enable support for building sub-devices as modules,
+	  choose M here.
+
 config MFD_RDC321X
 	tristate "RDC R-321x southbridge"
 	select MFD_CORE
@@ -1202,7 +1212,7 @@ config MFD_SI476X_CORE
 	  module will be called si476x-core.
 
 config MFD_SIMPLE_MFD_I2C
-	tristate "Simple Multi-Functional Device support (I2C)"
+	tristate
 	depends on I2C
 	select MFD_CORE
 	select REGMAP_I2C
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index cbe0f96ca342..25041cc2f605 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -1236,6 +1236,7 @@ config REGULATOR_STW481X_VMMC
 
 config REGULATOR_SY7636A
 	tristate "Silergy SY7636A voltage regulator"
+	depends on MFD_SY7636A
 	help
 	  This driver supports Silergy SY3686A voltage regulator.
 
-- 
2.35.3

Re: [PATCH v21 1/4] mfd: silergy,sy7636a: Add config option

[Mark Brown]

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On Wed, May 25, 2022 at 09:55:51PM +1000, Alistair Francis wrote:
> Add a specific MFD_SY7636A config option.
> 
> As part of this change we can use MFD_SY7636A as a dependency for all
> SY7636a components and also remove the name from MFD_SIMPLE_MFD_I2C as
> it no longer needs to be selectable.

Acked-by: Mark Brown <broonie@kernel.org>

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Re: [PATCH v21 1/4] mfd: silergy,sy7636a: Add config option

[Lee Jones]

On Wed, 25 May 2022, Mark Brown wrote:

> On Wed, May 25, 2022 at 09:55:51PM +1000, Alistair Francis wrote:
> > Add a specific MFD_SY7636A config option.
> > 
> > As part of this change we can use MFD_SY7636A as a dependency for all
> > SY7636a components and also remove the name from MFD_SIMPLE_MFD_I2C as
> > it no longer needs to be selectable.
> 
> Acked-by: Mark Brown <broonie@kernel.org>

Full disclosure; I've already made my cut for v5.19.

This is due for v5.20.

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v21 1/4] mfd: silergy,sy7636a: Add config option

[Alistair Francis]

On Thu, May 26, 2022 at 6:30 PM Lee Jones <lee.jones@linaro.org> wrote:
>
> On Wed, 25 May 2022, Mark Brown wrote:
>
> > On Wed, May 25, 2022 at 09:55:51PM +1000, Alistair Francis wrote:
> > > Add a specific MFD_SY7636A config option.
> > >
> > > As part of this change we can use MFD_SY7636A as a dependency for all
> > > SY7636a components and also remove the name from MFD_SIMPLE_MFD_I2C as
> > > it no longer needs to be selectable.
> >
> > Acked-by: Mark Brown <broonie@kernel.org>
>
> Full disclosure; I've already made my cut for v5.19.
>
> This is due for v5.20.

I just wanted to double check that this is still going in for 5.20

Alistair

>
> --
> Lee Jones [李琼斯]
> Principal Technical Lead - Developer Services
> Linaro.org │ Open source software for Arm SoCs
> Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v21 1/4] mfd: silergy,sy7636a: Add config option

[Lee Jones]

On Wed, 25 May 2022, Alistair Francis wrote:

> Add a specific MFD_SY7636A config option.
> 
> As part of this change we can use MFD_SY7636A as a dependency for all
> SY7636a components and also remove the name from MFD_SIMPLE_MFD_I2C as
> it no longer needs to be selectable.
> 
> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  drivers/hwmon/Kconfig     |  1 +
>  drivers/mfd/Kconfig       | 12 +++++++++++-
>  drivers/regulator/Kconfig |  1 +
>  3 files changed, 13 insertions(+), 1 deletion(-)

Applied, thanks.

-- 
DEPRECATED: Please use lee@kernel.org

[PATCH v21 2/4] ARM: imx_v6_v7_defconfig: Enable silergy,sy7636a

[Alistair Francis]

Enable the silergy,sy7636a and silergy,sy7636a-regulator for the
reMarkable2.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 arch/arm/configs/imx_v6_v7_defconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig
index f7498df08dfe..81fe604bf4ec 100644
--- a/arch/arm/configs/imx_v6_v7_defconfig
+++ b/arch/arm/configs/imx_v6_v7_defconfig
@@ -223,6 +223,7 @@ CONFIG_RN5T618_POWER=m
 CONFIG_SENSORS_MC13783_ADC=y
 CONFIG_SENSORS_GPIO_FAN=y
 CONFIG_SENSORS_IIO_HWMON=y
+CONFIG_SENSORS_SY7636A=y
 CONFIG_THERMAL_STATISTICS=y
 CONFIG_THERMAL_WRITABLE_TRIPS=y
 CONFIG_CPU_THERMAL=y
@@ -238,6 +239,7 @@ CONFIG_MFD_DA9062=y
 CONFIG_MFD_DA9063=y
 CONFIG_MFD_MC13XXX_SPI=y
 CONFIG_MFD_MC13XXX_I2C=y
+CONFIG_MFD_SY7636A=y
 CONFIG_MFD_RN5T618=y
 CONFIG_MFD_STMPE=y
 CONFIG_REGULATOR_FIXED_VOLTAGE=y
@@ -251,6 +253,7 @@ CONFIG_REGULATOR_MC13783=y
 CONFIG_REGULATOR_MC13892=y
 CONFIG_REGULATOR_PFUZE100=y
 CONFIG_REGULATOR_RN5T618=y
+CONFIG_REGULATOR_SY7636A=y
 CONFIG_RC_CORE=y
 CONFIG_RC_DEVICES=y
 CONFIG_IR_GPIO_CIR=y
-- 
2.35.3

[PATCH v21 3/4] ARM: dts: imx7d-remarkable2: Enable silergy,sy7636a

[Alistair Francis]

Enable the silergy,sy7636a and silergy,sy7636a-regulator on the
reMarkable2.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 arch/arm/boot/dts/imx7d-remarkable2.dts | 62 +++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/arch/arm/boot/dts/imx7d-remarkable2.dts b/arch/arm/boot/dts/imx7d-remarkable2.dts
index a2a91bfdd98e..99ac0d242936 100644
--- a/arch/arm/boot/dts/imx7d-remarkable2.dts
+++ b/arch/arm/boot/dts/imx7d-remarkable2.dts
@@ -22,6 +22,27 @@ memory@80000000 {
 		reg = <0x80000000 0x40000000>;
 	};
 
+	thermal-zones {
+		epd-thermal {
+			thermal-sensors = <&epd_pmic>;
+			polling-delay-passive = <30000>;
+			polling-delay = <30000>;
+			trips {
+				trip0 {
+					temperature = <49000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				trip1 {
+					temperature = <50000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+		};
+	};
+
 	reg_brcm: regulator-brcm {
 		compatible = "regulator-fixed";
 		regulator-name = "brcm_reg";
@@ -84,6 +105,33 @@ wacom_digitizer: digitizer@9 {
 	};
 };
 
+&i2c4 {
+	clock-frequency = <100000>;
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&pinctrl_i2c4>;
+	pinctrl-1 = <&pinctrl_i2c4>;
+	status = "okay";
+
+	epd_pmic: sy7636a@62 {
+		compatible = "silergy,sy7636a";
+		reg = <0x62>;
+		status = "okay";
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_epdpmic>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		#thermal-sensor-cells = <0>;
+
+		epd-pwr-good-gpios = <&gpio6 21 GPIO_ACTIVE_HIGH>;
+		regulators {
+			reg_epdpmic: vcom {
+				regulator-name = "vcom";
+				regulator-boot-on;
+			};
+		};
+	};
+};
+
 &snvs_pwrkey {
 	status = "okay";
 };
@@ -177,6 +225,13 @@ MX7D_PAD_SAI1_TX_BCLK__GPIO6_IO13	0x14
 		>;
 	};
 
+	pinctrl_epdpmic: epdpmicgrp {
+		fsl,pins = <
+			MX7D_PAD_SAI2_RX_DATA__GPIO6_IO21 0x00000074
+			MX7D_PAD_ENET1_RGMII_TXC__GPIO7_IO11 0x00000014
+		>;
+	};
+
 	pinctrl_i2c1: i2c1grp {
 		fsl,pins = <
 			MX7D_PAD_I2C1_SDA__I2C1_SDA		0x4000007f
@@ -184,6 +239,13 @@ MX7D_PAD_I2C1_SCL__I2C1_SCL		0x4000007f
 		>;
 	};
 
+	pinctrl_i2c4: i2c4grp {
+		fsl,pins = <
+			MX7D_PAD_I2C4_SDA__I2C4_SDA		0x4000007f
+			MX7D_PAD_I2C4_SCL__I2C4_SCL		0x4000007f
+		>;
+	};
+
 	pinctrl_uart1: uart1grp {
 		fsl,pins = <
 			MX7D_PAD_UART1_TX_DATA__UART1_DCE_TX	0x79
-- 
2.35.3

[PATCH v21 4/4] ARM: dts: imx7d-remarkable2: Enable lcdif

[Alistair Francis]

Connect the dispaly on the reMarkable2.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 arch/arm/boot/dts/imx7d-remarkable2.dts | 74 +++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/arch/arm/boot/dts/imx7d-remarkable2.dts b/arch/arm/boot/dts/imx7d-remarkable2.dts
index 99ac0d242936..03a4029e1e57 100644
--- a/arch/arm/boot/dts/imx7d-remarkable2.dts
+++ b/arch/arm/boot/dts/imx7d-remarkable2.dts
@@ -68,6 +68,16 @@ reg_digitizer: regulator-digitizer {
 		startup-delay-us = <100000>; /* 100 ms */
 	};
 
+	reg_sdoe: regulator-sdoe {
+		compatible = "regulator-fixed";
+		regulator-name = "SDOE";
+		pinctrl-names = "default", "sleep";
+		pinctrl-0 = <&pinctrl_sdoe_reg>;
+		pinctrl-1 = <&pinctrl_sdoe_reg>;
+		gpio = <&gpio3 27 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+	};
+
 	wifi_pwrseq: wifi_pwrseq {
 		compatible = "mmc-pwrseq-simple";
 		pinctrl-names = "default";
@@ -76,6 +86,16 @@ wifi_pwrseq: wifi_pwrseq {
 		clocks = <&clks IMX7D_CLKO2_ROOT_DIV>;
 		clock-names = "ext_clock";
 	};
+
+	panel {
+		compatible = "eink,vb3300-kca";
+
+		port {
+			panel_in: endpoint {
+				remote-endpoint = <&display_out>;
+			};
+		};
+	};
 };
 
 &clks {
@@ -132,6 +152,20 @@ reg_epdpmic: vcom {
 	};
 };
 
+&lcdif {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_lcdif>;
+	lcd-supply = <&reg_epdpmic>;
+	lcd2-supply = <&reg_sdoe>;
+	status = "okay";
+
+	port {
+		display_out: endpoint {
+			remote-endpoint = <&panel_in>;
+		};
+	};
+};
+
 &snvs_pwrkey {
 	status = "okay";
 };
@@ -246,6 +280,46 @@ MX7D_PAD_I2C4_SCL__I2C4_SCL		0x4000007f
 		>;
 	};
 
+	pinctrl_lcdif: lcdifgrp {
+		fsl,pins = <
+			MX7D_PAD_LCD_DATA00__LCD_DATA0		0x79
+			MX7D_PAD_LCD_DATA01__LCD_DATA1		0x79
+			MX7D_PAD_LCD_DATA02__LCD_DATA2		0x79
+			MX7D_PAD_LCD_DATA03__LCD_DATA3		0x79
+			MX7D_PAD_LCD_DATA04__LCD_DATA4		0x79
+			MX7D_PAD_LCD_DATA05__LCD_DATA5		0x79
+			MX7D_PAD_LCD_DATA06__LCD_DATA6		0x79
+			MX7D_PAD_LCD_DATA07__LCD_DATA7		0x79
+			MX7D_PAD_LCD_DATA08__LCD_DATA8		0x79
+			MX7D_PAD_LCD_DATA09__LCD_DATA9		0x79
+			MX7D_PAD_LCD_DATA10__LCD_DATA10		0x79
+			MX7D_PAD_LCD_DATA11__LCD_DATA11		0x79
+			MX7D_PAD_LCD_DATA12__LCD_DATA12		0x79
+			MX7D_PAD_LCD_DATA13__LCD_DATA13		0x79
+			MX7D_PAD_LCD_DATA14__LCD_DATA14		0x79
+			MX7D_PAD_LCD_DATA15__LCD_DATA15		0x79
+
+			MX7D_PAD_LCD_DATA17__LCD_DATA17		0x79
+			MX7D_PAD_LCD_DATA18__LCD_DATA18		0x79
+			MX7D_PAD_LCD_DATA19__LCD_DATA19		0x79
+			MX7D_PAD_LCD_DATA20__LCD_DATA20		0x79
+			MX7D_PAD_LCD_DATA21__LCD_DATA21		0x79
+
+			MX7D_PAD_LCD_DATA23__LCD_DATA23		0x79
+			MX7D_PAD_LCD_CLK__LCD_CLK		0x79
+			MX7D_PAD_LCD_ENABLE__LCD_ENABLE		0x79
+			MX7D_PAD_LCD_VSYNC__LCD_VSYNC		0x79
+			MX7D_PAD_LCD_HSYNC__LCD_HSYNC		0x79
+			MX7D_PAD_LCD_RESET__LCD_RESET		0x79
+		>;
+	};
+
+	pinctrl_sdoe_reg: sdoereggrp {
+		fsl,pins = <
+			MX7D_PAD_LCD_DATA22__GPIO3_IO27		0x74
+		>;
+	};
+
 	pinctrl_uart1: uart1grp {
 		fsl,pins = <
 			MX7D_PAD_UART1_TX_DATA__UART1_DCE_TX	0x79
-- 
2.35.3

Re: [PATCH v21 4/4] ARM: dts: imx7d-remarkable2: Enable lcdif

[Samuel Holland]

Hi Alistair,

On 5/25/22 6:55 AM, Alistair Francis wrote:
> Connect the dispaly on the reMarkable2.
> 
> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> ---
>  arch/arm/boot/dts/imx7d-remarkable2.dts | 74 +++++++++++++++++++++++++
>  1 file changed, 74 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/imx7d-remarkable2.dts b/arch/arm/boot/dts/imx7d-remarkable2.dts
> index 99ac0d242936..03a4029e1e57 100644
> --- a/arch/arm/boot/dts/imx7d-remarkable2.dts
> +++ b/arch/arm/boot/dts/imx7d-remarkable2.dts
> @@ -68,6 +68,16 @@ reg_digitizer: regulator-digitizer {
>  		startup-delay-us = <100000>; /* 100 ms */
>  	};
>  
> +	reg_sdoe: regulator-sdoe {
> +		compatible = "regulator-fixed";
> +		regulator-name = "SDOE";
> +		pinctrl-names = "default", "sleep";
> +		pinctrl-0 = <&pinctrl_sdoe_reg>;
> +		pinctrl-1 = <&pinctrl_sdoe_reg>;
> +		gpio = <&gpio3 27 GPIO_ACTIVE_HIGH>;
> +		enable-active-high;
> +	};
> +
>  	wifi_pwrseq: wifi_pwrseq {
>  		compatible = "mmc-pwrseq-simple";
>  		pinctrl-names = "default";
> @@ -76,6 +86,16 @@ wifi_pwrseq: wifi_pwrseq {
>  		clocks = <&clks IMX7D_CLKO2_ROOT_DIV>;
>  		clock-names = "ext_clock";
>  	};
> +
> +	panel {
> +		compatible = "eink,vb3300-kca";
> +
> +		port {
> +			panel_in: endpoint {
> +				remote-endpoint = <&display_out>;
> +			};
> +		};
> +	};

From the discussion at [1], this is not safe to merge. It exposes an
electrophoretic display to fbcon/userspace as if it was an LCD, which it very
much is not. Trying to write RGB pixel data to the panel could damage it.

So at the very least before hooking this up, the LCD controller has to know that
the EPD needs special handling and that it cannot accept RGB.

That doesn't necessarily mean there is a problem with the content of this patch
-- the special handling may all be taken care of based on the compatible string
-- but I think it's a really bad idea to merge this with how "eink,vb3300-kca"
is currently represented in panel-simple.

Regards,
Samuel

[1]: https://lore.kernel.org/lkml/Yo5kz%2F9cSd6ewC5f@phenom.ffwll.local/

>  };
>  
>  &clks {
> @@ -132,6 +152,20 @@ reg_epdpmic: vcom {
>  	};
>  };
>  
> +&lcdif {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&pinctrl_lcdif>;
> +	lcd-supply = <&reg_epdpmic>;
> +	lcd2-supply = <&reg_sdoe>;
> +	status = "okay";
> +
> +	port {
> +		display_out: endpoint {
> +			remote-endpoint = <&panel_in>;
> +		};
> +	};
> +};
> +
>  &snvs_pwrkey {
>  	status = "okay";
>  };
> @@ -246,6 +280,46 @@ MX7D_PAD_I2C4_SCL__I2C4_SCL		0x4000007f
>  		>;
>  	};
>  
> +	pinctrl_lcdif: lcdifgrp {
> +		fsl,pins = <
> +			MX7D_PAD_LCD_DATA00__LCD_DATA0		0x79
> +			MX7D_PAD_LCD_DATA01__LCD_DATA1		0x79
> +			MX7D_PAD_LCD_DATA02__LCD_DATA2		0x79
> +			MX7D_PAD_LCD_DATA03__LCD_DATA3		0x79
> +			MX7D_PAD_LCD_DATA04__LCD_DATA4		0x79
> +			MX7D_PAD_LCD_DATA05__LCD_DATA5		0x79
> +			MX7D_PAD_LCD_DATA06__LCD_DATA6		0x79
> +			MX7D_PAD_LCD_DATA07__LCD_DATA7		0x79
> +			MX7D_PAD_LCD_DATA08__LCD_DATA8		0x79
> +			MX7D_PAD_LCD_DATA09__LCD_DATA9		0x79
> +			MX7D_PAD_LCD_DATA10__LCD_DATA10		0x79
> +			MX7D_PAD_LCD_DATA11__LCD_DATA11		0x79
> +			MX7D_PAD_LCD_DATA12__LCD_DATA12		0x79
> +			MX7D_PAD_LCD_DATA13__LCD_DATA13		0x79
> +			MX7D_PAD_LCD_DATA14__LCD_DATA14		0x79
> +			MX7D_PAD_LCD_DATA15__LCD_DATA15		0x79
> +
> +			MX7D_PAD_LCD_DATA17__LCD_DATA17		0x79
> +			MX7D_PAD_LCD_DATA18__LCD_DATA18		0x79
> +			MX7D_PAD_LCD_DATA19__LCD_DATA19		0x79
> +			MX7D_PAD_LCD_DATA20__LCD_DATA20		0x79
> +			MX7D_PAD_LCD_DATA21__LCD_DATA21		0x79
> +
> +			MX7D_PAD_LCD_DATA23__LCD_DATA23		0x79
> +			MX7D_PAD_LCD_CLK__LCD_CLK		0x79
> +			MX7D_PAD_LCD_ENABLE__LCD_ENABLE		0x79
> +			MX7D_PAD_LCD_VSYNC__LCD_VSYNC		0x79
> +			MX7D_PAD_LCD_HSYNC__LCD_HSYNC		0x79
> +			MX7D_PAD_LCD_RESET__LCD_RESET		0x79
> +		>;
> +	};
> +
> +	pinctrl_sdoe_reg: sdoereggrp {
> +		fsl,pins = <
> +			MX7D_PAD_LCD_DATA22__GPIO3_IO27		0x74
> +		>;
> +	};
> +
>  	pinctrl_uart1: uart1grp {
>  		fsl,pins = <
>  			MX7D_PAD_UART1_TX_DATA__UART1_DCE_TX	0x79
> 

Re: [PATCH v21 4/4] ARM: dts: imx7d-remarkable2: Enable lcdif

[Alistair Francis]

On Sun, May 29, 2022 at 4:20 AM Samuel Holland <samuel@sholland.org> wrote:
>
> Hi Alistair,
>
> On 5/25/22 6:55 AM, Alistair Francis wrote:
> > Connect the dispaly on the reMarkable2.
> >
> > Signed-off-by: Alistair Francis <alistair@alistair23.me>
> > ---
> >  arch/arm/boot/dts/imx7d-remarkable2.dts | 74 +++++++++++++++++++++++++
> >  1 file changed, 74 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/imx7d-remarkable2.dts b/arch/arm/boot/dts/imx7d-remarkable2.dts
> > index 99ac0d242936..03a4029e1e57 100644
> > --- a/arch/arm/boot/dts/imx7d-remarkable2.dts
> > +++ b/arch/arm/boot/dts/imx7d-remarkable2.dts
> > @@ -68,6 +68,16 @@ reg_digitizer: regulator-digitizer {
> >               startup-delay-us = <100000>; /* 100 ms */
> >       };
> >
> > +     reg_sdoe: regulator-sdoe {
> > +             compatible = "regulator-fixed";
> > +             regulator-name = "SDOE";
> > +             pinctrl-names = "default", "sleep";
> > +             pinctrl-0 = <&pinctrl_sdoe_reg>;
> > +             pinctrl-1 = <&pinctrl_sdoe_reg>;
> > +             gpio = <&gpio3 27 GPIO_ACTIVE_HIGH>;
> > +             enable-active-high;
> > +     };
> > +
> >       wifi_pwrseq: wifi_pwrseq {
> >               compatible = "mmc-pwrseq-simple";
> >               pinctrl-names = "default";
> > @@ -76,6 +86,16 @@ wifi_pwrseq: wifi_pwrseq {
> >               clocks = <&clks IMX7D_CLKO2_ROOT_DIV>;
> >               clock-names = "ext_clock";
> >       };
> > +
> > +     panel {
> > +             compatible = "eink,vb3300-kca";
> > +
> > +             port {
> > +                     panel_in: endpoint {
> > +                             remote-endpoint = <&display_out>;
> > +                     };
> > +             };
> > +     };
>
> From the discussion at [1], this is not safe to merge. It exposes an
> electrophoretic display to fbcon/userspace as if it was an LCD, which it very
> much is not. Trying to write RGB pixel data to the panel could damage it.

Hey Samuel,

From what I can tell it's difficult to damage the display, but I see your point.

>
> So at the very least before hooking this up, the LCD controller has to know that
> the EPD needs special handling and that it cannot accept RGB.

Looking at [1] it seems like no decision was made about how to handle
a case like this where the EPC driving is all done in software. We
currently drive it from userspace via proprietary software. It seems
unlikely we will be able to support this in the kernel, so it would be
nice to somehow expose it to userspace.

>
> That doesn't necessarily mean there is a problem with the content of this patch
> -- the special handling may all be taken care of based on the compatible string

Ah ok. So it sounds like adding a check to the LCD controller based on
compatible string to reject RGB values would be a good start here.
That would at least block bogus values from making it to the screen

Alistair

> -- but I think it's a really bad idea to merge this with how "eink,vb3300-kca"
> is currently represented in panel-simple.
>
> Regards,
> Samuel
>
> [1]: https://lore.kernel.org/lkml/Yo5kz%2F9cSd6ewC5f@phenom.ffwll.local/
>
> >  };
> >
> >  &clks {
> > @@ -132,6 +152,20 @@ reg_epdpmic: vcom {
> >       };
> >  };
> >
> > +&lcdif {
> > +     pinctrl-names = "default";
> > +     pinctrl-0 = <&pinctrl_lcdif>;
> > +     lcd-supply = <&reg_epdpmic>;
> > +     lcd2-supply = <&reg_sdoe>;
> > +     status = "okay";
> > +
> > +     port {
> > +             display_out: endpoint {
> > +                     remote-endpoint = <&panel_in>;
> > +             };
> > +     };
> > +};
> > +
> >  &snvs_pwrkey {
> >       status = "okay";
> >  };
> > @@ -246,6 +280,46 @@ MX7D_PAD_I2C4_SCL__I2C4_SCL              0x4000007f
> >               >;
> >       };
> >
> > +     pinctrl_lcdif: lcdifgrp {
> > +             fsl,pins = <
> > +                     MX7D_PAD_LCD_DATA00__LCD_DATA0          0x79
> > +                     MX7D_PAD_LCD_DATA01__LCD_DATA1          0x79
> > +                     MX7D_PAD_LCD_DATA02__LCD_DATA2          0x79
> > +                     MX7D_PAD_LCD_DATA03__LCD_DATA3          0x79
> > +                     MX7D_PAD_LCD_DATA04__LCD_DATA4          0x79
> > +                     MX7D_PAD_LCD_DATA05__LCD_DATA5          0x79
> > +                     MX7D_PAD_LCD_DATA06__LCD_DATA6          0x79
> > +                     MX7D_PAD_LCD_DATA07__LCD_DATA7          0x79
> > +                     MX7D_PAD_LCD_DATA08__LCD_DATA8          0x79
> > +                     MX7D_PAD_LCD_DATA09__LCD_DATA9          0x79
> > +                     MX7D_PAD_LCD_DATA10__LCD_DATA10         0x79
> > +                     MX7D_PAD_LCD_DATA11__LCD_DATA11         0x79
> > +                     MX7D_PAD_LCD_DATA12__LCD_DATA12         0x79
> > +                     MX7D_PAD_LCD_DATA13__LCD_DATA13         0x79
> > +                     MX7D_PAD_LCD_DATA14__LCD_DATA14         0x79
> > +                     MX7D_PAD_LCD_DATA15__LCD_DATA15         0x79
> > +
> > +                     MX7D_PAD_LCD_DATA17__LCD_DATA17         0x79
> > +                     MX7D_PAD_LCD_DATA18__LCD_DATA18         0x79
> > +                     MX7D_PAD_LCD_DATA19__LCD_DATA19         0x79
> > +                     MX7D_PAD_LCD_DATA20__LCD_DATA20         0x79
> > +                     MX7D_PAD_LCD_DATA21__LCD_DATA21         0x79
> > +
> > +                     MX7D_PAD_LCD_DATA23__LCD_DATA23         0x79
> > +                     MX7D_PAD_LCD_CLK__LCD_CLK               0x79
> > +                     MX7D_PAD_LCD_ENABLE__LCD_ENABLE         0x79
> > +                     MX7D_PAD_LCD_VSYNC__LCD_VSYNC           0x79
> > +                     MX7D_PAD_LCD_HSYNC__LCD_HSYNC           0x79
> > +                     MX7D_PAD_LCD_RESET__LCD_RESET           0x79
> > +             >;
> > +     };
> > +
> > +     pinctrl_sdoe_reg: sdoereggrp {
> > +             fsl,pins = <
> > +                     MX7D_PAD_LCD_DATA22__GPIO3_IO27         0x74
> > +             >;
> > +     };
> > +
> >       pinctrl_uart1: uart1grp {
> >               fsl,pins = <
> >                       MX7D_PAD_UART1_TX_DATA__UART1_DCE_TX    0x79
> >
>