[PATCH v2 0/4] Add channel type support to pwm-cros-ec

[PATCH v2 0/4] Add channel type support to pwm-cros-ec

[Fabio Baltieri]

Hi,

The ChromiumOS EC PWM host command protocol supports specifying the
requested PWM by type rather than channel. [1]

This series adds support for specifying PWM by type rather than channel
number in the pwm-cros-ec driver, which abstracts the node definitions
from the actual hardware configuration from the kernel perspective,
aligns the API with the one used by the bootloader, and allows removing
some dtsi overrides.

Tested on a sc7180-trogdor board, but on a version based on an older
kernel, so this exact series is build only tested.

Changes from v1:
(https://patchwork.kernel.org/project/chrome-platform/list/?series=625182)
- fixed the dt include file license
- fixed the property name (s/_/-/)
- rebased on current linus tree (few dts files changed from a soc tree
  pull, so patch 4 needs a recent base to apply correctly)

[1] https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/platform/ec/common/pwm.c;l=24
[2] https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/platform/depthcharge/src/drivers/ec/cros/ec.c;l=1271-1273

Fabio Baltieri (4):
  dt-bindings: add mfd/cros_ec definitions
  drivers: pwm: pwm-cros-ec: add channel type support
  dt-bindings: update google,cros-ec-pwm documentation
  arm64: dts: address cros-ec-pwm channels by type

 .../bindings/pwm/google,cros-ec-pwm.yaml      |  6 ++
 .../mt8183-kukui-jacuzzi-fennel-sku1.dts      |  4 +-
 .../dts/mediatek/mt8183-kukui-jacuzzi.dtsi    |  3 +-
 .../arm64/boot/dts/mediatek/mt8183-kukui.dtsi |  1 +
 .../boot/dts/qcom/sc7180-trogdor-coachz.dtsi  |  4 -
 arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi  |  8 +-
 .../qcom/sc7280-herobrine-herobrine-r0.dts    |  6 +-
 .../arm64/boot/dts/qcom/sc7280-herobrine.dtsi |  6 +-
 .../arm64/boot/dts/qcom/sc7280-idp-ec-h1.dtsi |  3 +-
 arch/arm64/boot/dts/qcom/sdm845-cheza.dtsi    |  6 +-
 .../boot/dts/rockchip/rk3399-gru-bob.dts      |  4 -
 .../dts/rockchip/rk3399-gru-chromebook.dtsi   |  4 +-
 .../boot/dts/rockchip/rk3399-gru-kevin.dts    |  4 -
 arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi  |  1 +
 drivers/pwm/pwm-cros-ec.c                     | 80 +++++++++++++++----
 include/dt-bindings/mfd/cros_ec.h             | 18 +++++
 16 files changed, 117 insertions(+), 41 deletions(-)
 create mode 100644 include/dt-bindings/mfd/cros_ec.h

-- 
2.35.1.1021.g381101b075-goog

[PATCH v2 1/4] dt-bindings: add mfd/cros_ec definitions

[Fabio Baltieri]

Add a dt-bindings include file for cros_ec devicetree definition, define
a pair of special purpose PWM channels in it.

Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
---
 include/dt-bindings/mfd/cros_ec.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 include/dt-bindings/mfd/cros_ec.h

diff --git a/include/dt-bindings/mfd/cros_ec.h b/include/dt-bindings/mfd/cros_ec.h
new file mode 100644
index 000000000000..3b29cd049578
--- /dev/null
+++ b/include/dt-bindings/mfd/cros_ec.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * DTS binding definitions used for the Chromium OS Embedded Controller.
+ *
+ * Copyright (c) 2022 The Chromium OS Authors. All rights reserved.
+ */
+
+#ifndef _DT_BINDINGS_MFD_CROS_EC_H
+#define _DT_BINDINGS_MFD_CROS_EC_H
+
+/* Typed channel for keyboard backlight. */
+#define CROS_EC_PWM_DT_KB_LIGHT		0
+/* Typed channel for display backlight. */
+#define CROS_EC_PWM_DT_DISPLAY_LIGHT	1
+/* Number of typed channels. */
+#define CROS_EC_PWM_DT_COUNT		2
+
+#endif
-- 
2.35.1.1021.g381101b075-goog

[PATCH v2 2/4] drivers: pwm: pwm-cros-ec: add channel type support

[Fabio Baltieri]

Add support for EC_PWM_TYPE_DISPLAY_LIGHT and EC_PWM_TYPE_KB_LIGHT pwm
types to the PWM cros_ec_pwm driver. This allows specifying one of these
PWM channel by functionality, and let the EC firmware pick the correct
channel, thus abstracting the hardware implementation from the kernel
driver.

Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
---
 drivers/pwm/pwm-cros-ec.c | 80 +++++++++++++++++++++++++++++++--------
 1 file changed, 65 insertions(+), 15 deletions(-)

diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
index 5e29d9c682c3..051791f5d024 100644
--- a/drivers/pwm/pwm-cros-ec.c
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -12,17 +12,21 @@
 #include <linux/pwm.h>
 #include <linux/slab.h>
 
+#include <dt-bindings/mfd/cros_ec.h>
+
 /**
  * struct cros_ec_pwm_device - Driver data for EC PWM
  *
  * @dev: Device node
  * @ec: Pointer to EC device
  * @chip: PWM controller chip
+ * @use_pwm_type: Use PWM types instead of generic channels
  */
 struct cros_ec_pwm_device {
 	struct device *dev;
 	struct cros_ec_device *ec;
 	struct pwm_chip chip;
+	bool use_pwm_type;
 };
 
 /**
@@ -58,14 +62,31 @@ static void cros_ec_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 	kfree(channel);
 }
 
-static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
+static int cros_ec_dt_type_to_pwm_type(u8 dt_index, u8 *pwm_type)
 {
+	switch (dt_index) {
+	case CROS_EC_PWM_DT_KB_LIGHT:
+		*pwm_type = EC_PWM_TYPE_KB_LIGHT;
+		return 0;
+	case CROS_EC_PWM_DT_DISPLAY_LIGHT:
+		*pwm_type = EC_PWM_TYPE_DISPLAY_LIGHT;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int cros_ec_pwm_set_duty(struct cros_ec_pwm_device *ec_pwm, u8 index,
+				u16 duty)
+{
+	struct cros_ec_device *ec = ec_pwm->ec;
 	struct {
 		struct cros_ec_command msg;
 		struct ec_params_pwm_set_duty params;
 	} __packed buf;
 	struct ec_params_pwm_set_duty *params = &buf.params;
 	struct cros_ec_command *msg = &buf.msg;
+	int ret;
 
 	memset(&buf, 0, sizeof(buf));
 
@@ -75,14 +96,25 @@ static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
 	msg->outsize = sizeof(*params);
 
 	params->duty = duty;
-	params->pwm_type = EC_PWM_TYPE_GENERIC;
-	params->index = index;
+
+	if (ec_pwm->use_pwm_type) {
+		ret = cros_ec_dt_type_to_pwm_type(index, &params->pwm_type);
+		if (ret) {
+			dev_err(ec->dev, "Invalid PWM type index: %d\n", index);
+			return ret;
+		}
+		params->index = 0;
+	} else {
+		params->pwm_type = EC_PWM_TYPE_GENERIC;
+		params->index = index;
+	}
 
 	return cros_ec_cmd_xfer_status(ec, msg);
 }
 
-static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
+static int cros_ec_pwm_get_duty(struct cros_ec_pwm_device *ec_pwm, u8 index)
 {
+	struct cros_ec_device *ec = ec_pwm->ec;
 	struct {
 		struct cros_ec_command msg;
 		union {
@@ -102,8 +134,17 @@ static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
 	msg->insize = sizeof(*resp);
 	msg->outsize = sizeof(*params);
 
-	params->pwm_type = EC_PWM_TYPE_GENERIC;
-	params->index = index;
+	if (ec_pwm->use_pwm_type) {
+		ret = cros_ec_dt_type_to_pwm_type(index, &params->pwm_type);
+		if (ret) {
+			dev_err(ec->dev, "Invalid PWM type index: %d\n", index);
+			return ret;
+		}
+		params->index = 0;
+	} else {
+		params->pwm_type = EC_PWM_TYPE_GENERIC;
+		params->index = index;
+	}
 
 	ret = cros_ec_cmd_xfer_status(ec, msg);
 	if (ret < 0)
@@ -133,7 +174,7 @@ static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 */
 	duty_cycle = state->enabled ? state->duty_cycle : 0;
 
-	ret = cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
+	ret = cros_ec_pwm_set_duty(ec_pwm, pwm->hwpwm, duty_cycle);
 	if (ret < 0)
 		return ret;
 
@@ -149,7 +190,7 @@ static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
 	int ret;
 
-	ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
+	ret = cros_ec_pwm_get_duty(ec_pwm, pwm->hwpwm);
 	if (ret < 0) {
 		dev_err(chip->dev, "error getting initial duty: %d\n", ret);
 		return;
@@ -204,13 +245,13 @@ static const struct pwm_ops cros_ec_pwm_ops = {
  * of PWMs it supports directly, so we have to read the pwm duty cycle for
  * subsequent channels until we get an error.
  */
-static int cros_ec_num_pwms(struct cros_ec_device *ec)
+static int cros_ec_num_pwms(struct cros_ec_pwm_device *ec_pwm)
 {
 	int i, ret;
 
 	/* The index field is only 8 bits */
 	for (i = 0; i <= U8_MAX; i++) {
-		ret = cros_ec_pwm_get_duty(ec, i);
+		ret = cros_ec_pwm_get_duty(ec_pwm, i);
 		/*
 		 * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM
 		 * responses; everything else is treated as an error.
@@ -251,17 +292,26 @@ static int cros_ec_pwm_probe(struct platform_device *pdev)
 	chip = &ec_pwm->chip;
 	ec_pwm->ec = ec;
 
+	ec_pwm->use_pwm_type = of_property_read_bool(
+			dev->of_node, "google,use-pwm-type");
+
 	/* PWM chip */
 	chip->dev = dev;
 	chip->ops = &cros_ec_pwm_ops;
 	chip->of_xlate = cros_ec_pwm_xlate;
 	chip->of_pwm_n_cells = 1;
-	ret = cros_ec_num_pwms(ec);
-	if (ret < 0) {
-		dev_err(dev, "Couldn't find PWMs: %d\n", ret);
-		return ret;
+
+	if (ec_pwm->use_pwm_type) {
+		chip->npwm = CROS_EC_PWM_DT_COUNT;
+	} else {
+		ret = cros_ec_num_pwms(ec_pwm);
+		if (ret < 0) {
+			dev_err(dev, "Couldn't find PWMs: %d\n", ret);
+			return ret;
+		}
+		chip->npwm = ret;
 	}
-	chip->npwm = ret;
+
 	dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);
 
 	ret = pwmchip_add(chip);
-- 
2.35.1.1021.g381101b075-goog

[PATCH v2 3/4] dt-bindings: update google,cros-ec-pwm documentation

[Fabio Baltieri]

Update google,cros-ec-pwm node documentation to mention the
google,use_pwm_type property.

Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
---
 .../devicetree/bindings/pwm/google,cros-ec-pwm.yaml         | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
index 4cfbffd8414a..9c895c990ed8 100644
--- a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
+++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
@@ -19,6 +19,12 @@ description: |
 properties:
   compatible:
     const: google,cros-ec-pwm
+
+  google,use-pwm-type:
+    description:
+      Use PWM types (CROS_EC_PWM_DT_<...>) instead of generic channels.
+    type: boolean
+
   "#pwm-cells":
     description: The cell specifies the PWM index.
     const: 1
-- 
2.35.1.1021.g381101b075-goog

[PATCH v2 4/4] arm64: dts: address cros-ec-pwm channels by type

[Fabio Baltieri]

Update various cros-ec-pwm board definitions to address the keyboard and
screen backlight PWM channels by type rather than channel number. This
makes the instance independent by the actual hardware configuration,
relying on the EC firmware to pick the right channel, and allows
dropping few dtsi overrides as a consequence.

Changed the node label used to cros_ec_pwm_type to avoid ambiguity about
the pwm cell meaning.

Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
---
 .../dts/mediatek/mt8183-kukui-jacuzzi-fennel-sku1.dts     | 4 ++--
 arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi    | 3 ++-
 arch/arm64/boot/dts/mediatek/mt8183-kukui.dtsi            | 1 +
 arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi       | 4 ----
 arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi              | 8 +++++---
 .../arm64/boot/dts/qcom/sc7280-herobrine-herobrine-r0.dts | 6 ++++--
 arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi            | 6 ++++--
 arch/arm64/boot/dts/qcom/sc7280-idp-ec-h1.dtsi            | 3 ++-
 arch/arm64/boot/dts/qcom/sdm845-cheza.dtsi                | 6 ++++--
 arch/arm64/boot/dts/rockchip/rk3399-gru-bob.dts           | 4 ----
 arch/arm64/boot/dts/rockchip/rk3399-gru-chromebook.dtsi   | 4 +++-
 arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts         | 4 ----
 arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi              | 1 +
 13 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi-fennel-sku1.dts b/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi-fennel-sku1.dts
index dec11a4eb59e..e2554a313deb 100644
--- a/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi-fennel-sku1.dts
+++ b/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi-fennel-sku1.dts
@@ -15,13 +15,13 @@ pwmleds {
 		compatible = "pwm-leds";
 		keyboard_backlight: keyboard-backlight {
 			label = "cros_ec::kbd_backlight";
-			pwms = <&cros_ec_pwm 0>;
+			pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_KB_LIGHT>;
 			max-brightness = <1023>;
 		};
 	};
 };
 
-&cros_ec_pwm {
+&cros_ec_pwm_type {
 	status = "okay";
 };
 
diff --git a/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi b/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi
index 8f7bf33f607d..f70c549bae93 100644
--- a/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi
@@ -92,10 +92,11 @@ volume_up {
 };
 
 &cros_ec {
-	cros_ec_pwm: ec-pwm {
+	cros_ec_pwm_type: ec-pwm {
 		compatible = "google,cros-ec-pwm";
 		#pwm-cells = <1>;
 		status = "disabled";
+		google,use-pwm-type;
 	};
 };
 
diff --git a/arch/arm64/boot/dts/mediatek/mt8183-kukui.dtsi b/arch/arm64/boot/dts/mediatek/mt8183-kukui.dtsi
index 0f9480f91261..ff54687ab8bf 100644
--- a/arch/arm64/boot/dts/mediatek/mt8183-kukui.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8183-kukui.dtsi
@@ -7,6 +7,7 @@
 
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/mfd/cros_ec.h>
 #include "mt8183.dtsi"
 #include "mt6358.dtsi"
 
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi
index c81805ef2250..aea7c66d95e0 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi
@@ -77,10 +77,6 @@ &ap_spi_fp {
 	status = "okay";
 };
 
-&backlight {
-	pwms = <&cros_ec_pwm 0>;
-};
-
 &camcc {
 	status = "okay";
 };
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
index 732e1181af48..56f398b05b7b 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
@@ -8,6 +8,7 @@
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/input/gpio-keys.h>
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/mfd/cros_ec.h>
 #include <dt-bindings/regulator/qcom,rpmh-regulator.h>
 #include <dt-bindings/sound/sc7180-lpass.h>
 
@@ -316,7 +317,7 @@ backlight: backlight {
 		num-interpolated-steps = <64>;
 		default-brightness-level = <951>;
 
-		pwms = <&cros_ec_pwm 1>;
+		pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_DISPLAY_LIGHT>;
 		enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
 		power-supply = <&ppvar_sys>;
 		pinctrl-names = "default";
@@ -354,7 +355,7 @@ pwmleds {
 		keyboard_backlight: keyboard-backlight {
 			status = "disabled";
 			label = "cros_ec::kbd_backlight";
-			pwms = <&cros_ec_pwm 0>;
+			pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_KB_LIGHT>;
 			max-brightness = <1023>;
 		};
 	};
@@ -637,9 +638,10 @@ cros_ec: ec@0 {
 		pinctrl-0 = <&ap_ec_int_l>;
 		spi-max-frequency = <3000000>;
 
-		cros_ec_pwm: pwm {
+		cros_ec_pwm_type: pwm {
 			compatible = "google,cros-ec-pwm";
 			#pwm-cells = <1>;
+			google,use-pwm-type;
 		};
 
 		i2c_tunnel: i2c-tunnel {
diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine-herobrine-r0.dts b/arch/arm64/boot/dts/qcom/sc7280-herobrine-herobrine-r0.dts
index 1779d96c30f6..cc11de91cc2c 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-herobrine-herobrine-r0.dts
+++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine-herobrine-r0.dts
@@ -11,6 +11,7 @@
 #include <dt-bindings/iio/qcom,spmi-adc7-pmr735a.h>
 #include <dt-bindings/input/gpio-keys.h>
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/mfd/cros_ec.h>
 #include <dt-bindings/pinctrl/qcom,pmic-gpio.h>
 #include <dt-bindings/regulator/qcom,rpmh-regulator.h>
 
@@ -336,7 +337,7 @@ pwmleds {
 		keyboard_backlight: keyboard-backlight {
 			status = "disabled";
 			label = "cros_ec::kbd_backlight";
-			pwms = <&cros_ec_pwm 0>;
+			pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_KB_LIGHT>;
 			max-brightness = <1023>;
 		};
 	};
@@ -705,9 +706,10 @@ cros_ec: ec@0 {
 		pinctrl-0 = <&ap_ec_int_l>;
 		spi-max-frequency = <3000000>;
 
-		cros_ec_pwm: pwm {
+		cros_ec_pwm_type: pwm {
 			compatible = "google,cros-ec-pwm";
 			#pwm-cells = <1>;
+			google,use-pwm-type;
 		};
 
 		i2c_tunnel: i2c-tunnel {
diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
index dc17f2079695..e5a041226db6 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
@@ -15,6 +15,7 @@
 
 #include <dt-bindings/input/gpio-keys.h>
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/mfd/cros_ec.h>
 
 #include "sc7280-qcard.dtsi"
 #include "sc7280-chrome-common.dtsi"
@@ -288,7 +289,7 @@ pwmleds {
 		keyboard_backlight: keyboard-backlight {
 			status = "disabled";
 			label = "cros_ec::kbd_backlight";
-			pwms = <&cros_ec_pwm 0>;
+			pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_KB_LIGHT>;
 			max-brightness = <1023>;
 		};
 	};
@@ -421,9 +422,10 @@ cros_ec: ec@0 {
 		pinctrl-0 = <&ap_ec_int_l>;
 		spi-max-frequency = <3000000>;
 
-		cros_ec_pwm: pwm {
+		cros_ec_pwm_type: pwm {
 			compatible = "google,cros-ec-pwm";
 			#pwm-cells = <1>;
+			google,use-pwm-type;
 		};
 
 		i2c_tunnel: i2c-tunnel {
diff --git a/arch/arm64/boot/dts/qcom/sc7280-idp-ec-h1.dtsi b/arch/arm64/boot/dts/qcom/sc7280-idp-ec-h1.dtsi
index a7c346aa3b02..a8c189328ae3 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-idp-ec-h1.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-idp-ec-h1.dtsi
@@ -20,9 +20,10 @@ cros_ec: ec@0 {
 		pinctrl-0 = <&ap_ec_int_l>;
 		spi-max-frequency = <3000000>;
 
-		cros_ec_pwm: pwm {
+		cros_ec_pwm_type: pwm {
 			compatible = "google,cros-ec-pwm";
 			#pwm-cells = <1>;
+			google,use-pwm-type;
 		};
 
 		i2c_tunnel: i2c-tunnel {
diff --git a/arch/arm64/boot/dts/qcom/sdm845-cheza.dtsi b/arch/arm64/boot/dts/qcom/sdm845-cheza.dtsi
index e7e4cc5936aa..600b8ea69a5d 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-cheza.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845-cheza.dtsi
@@ -6,6 +6,7 @@
  */
 
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/mfd/cros_ec.h>
 #include <dt-bindings/regulator/qcom,rpmh-regulator.h>
 #include "sdm845.dtsi"
 
@@ -27,7 +28,7 @@ chosen {
 
 	backlight: backlight {
 		compatible = "pwm-backlight";
-		pwms = <&cros_ec_pwm 0>;
+		pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_DISPLAY_LIGHT>;
 		enable-gpios = <&tlmm 37 GPIO_ACTIVE_HIGH>;
 		power-supply = <&ppvar_sys>;
 		pinctrl-names = "default";
@@ -708,9 +709,10 @@ cros_ec: ec@0 {
 		pinctrl-0 = <&ec_ap_int_l>;
 		spi-max-frequency = <3000000>;
 
-		cros_ec_pwm: pwm {
+		cros_ec_pwm_type: pwm {
 			compatible = "google,cros-ec-pwm";
 			#pwm-cells = <1>;
+			google,use-pwm-type;
 		};
 
 		i2c_tunnel: i2c-tunnel {
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-gru-bob.dts b/arch/arm64/boot/dts/rockchip/rk3399-gru-bob.dts
index 31ebb4e5fd33..5a076c2564f6 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-gru-bob.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-gru-bob.dts
@@ -55,10 +55,6 @@ trackpad: trackpad@15 {
 	};
 };
 
-&backlight {
-	pwms = <&cros_ec_pwm 0>;
-};
-
 &cpu_alert0 {
 	temperature = <65000>;
 };
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-gru-chromebook.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-gru-chromebook.dtsi
index 3355fb90fa54..fece0176a3d2 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-gru-chromebook.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-gru-chromebook.dtsi
@@ -198,6 +198,7 @@ backlight: backlight {
 		power-supply = <&pp3300_disp>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&bl_en>;
+		pwms = <&cros_ec_pwm_type CROS_EC_PWM_DT_DISPLAY_LIGHT>;
 		pwm-delay-us = <10000>;
 	};
 
@@ -462,9 +463,10 @@ ap_i2c_tp: &i2c5 {
 };
 
 &cros_ec {
-	cros_ec_pwm: pwm {
+	cros_ec_pwm_type: pwm {
 		compatible = "google,cros-ec-pwm";
 		#pwm-cells = <1>;
+		google,use-pwm-type;
 	};
 
 	usbc_extcon1: extcon1 {
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts b/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts
index 6863689df06f..e959a33af34b 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-gru-kevin.dts
@@ -84,10 +84,6 @@ thermistor_ppvar_litcpu: thermistor-ppvar-litcpu {
 	};
 };
 
-&backlight {
-	pwms = <&cros_ec_pwm 1>;
-};
-
 &gpio_keys {
 	pinctrl-names = "default";
 	pinctrl-0 = <&bt_host_wake_l>, <&cpu1_pen_eject>;
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi
index 162f08bca0d4..181159e9982d 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi
@@ -6,6 +6,7 @@
  */
 
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/mfd/cros_ec.h>
 #include "rk3399.dtsi"
 #include "rk3399-op1-opp.dtsi"
 
-- 
2.35.1.1021.g381101b075-goog

Re: [PATCH v2 2/4] drivers: pwm: pwm-cros-ec: add channel type support

[Tzung-Bi Shih]

On Thu, Mar 31, 2022 at 12:58:16PM +0000, Fabio Baltieri wrote:
> Add support for EC_PWM_TYPE_DISPLAY_LIGHT and EC_PWM_TYPE_KB_LIGHT pwm
> types to the PWM cros_ec_pwm driver. This allows specifying one of these
> PWM channel by functionality, and let the EC firmware pick the correct
> channel, thus abstracting the hardware implementation from the kernel
> driver.
> 
> Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>

Taking `git log --oneline drivers/pwm/pwm-cros-ec.c` as examples, suggest to
remove "drivers: " prefix from the commit title.

Otherwise,
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>

Re: [PATCH v2 3/4] dt-bindings: update google,cros-ec-pwm documentation

[Rob Herring]

On Thu, Mar 31, 2022 at 12:58:17PM +0000, Fabio Baltieri wrote:
> Update google,cros-ec-pwm node documentation to mention the
> google,use_pwm_type property.
> 
> Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
> ---
>  .../devicetree/bindings/pwm/google,cros-ec-pwm.yaml         | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> index 4cfbffd8414a..9c895c990ed8 100644
> --- a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> +++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> @@ -19,6 +19,12 @@ description: |
>  properties:
>    compatible:
>      const: google,cros-ec-pwm
> +
> +  google,use-pwm-type:
> +    description:
> +      Use PWM types (CROS_EC_PWM_DT_<...>) instead of generic channels.
> +    type: boolean

Either do a new compatible string if the cell interpretation is mutually 
exclusive (channel number vs. type) or split the number space for the 
1st cell between type and channel number. IOW, set a bit (31?) to 
signify the number is a type, not a channel.

Rob

Re: [PATCH v2 3/4] dt-bindings: update google,cros-ec-pwm documentation

[Fabio Baltieri]

Hi Rob,

On Wed, Apr 06, 2022 at 10:41:45AM -0500, Rob Herring wrote:
> On Thu, Mar 31, 2022 at 12:58:17PM +0000, Fabio Baltieri wrote:
> > Update google,cros-ec-pwm node documentation to mention the
> > google,use_pwm_type property.
> > 
> > Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
> > ---
> >  .../devicetree/bindings/pwm/google,cros-ec-pwm.yaml         | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > index 4cfbffd8414a..9c895c990ed8 100644
> > --- a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > +++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > @@ -19,6 +19,12 @@ description: |
> >  properties:
> >    compatible:
> >      const: google,cros-ec-pwm
> > +
> > +  google,use-pwm-type:
> > +    description:
> > +      Use PWM types (CROS_EC_PWM_DT_<...>) instead of generic channels.
> > +    type: boolean
> 
> Either do a new compatible string if the cell interpretation is mutually 
> exclusive (channel number vs. type) or split the number space for the 
> 1st cell between type and channel number. IOW, set a bit (31?) to 
> signify the number is a type, not a channel.

Split the number space was my first (tentative) implementation as well,
but it turns out that the PWM subsystem really wants channels to be
zero-based[1], so I don't think flags or bitmasks are really an option.

New compatible sounds good though, I'll rework a v3 with that change.

Thanks!
Fabio

[1] https://elixir.bootlin.com/linux/v5.17/source/drivers/pwm/core.c#L423

-- 
Fabio Baltieri

Re: [PATCH v2 3/4] dt-bindings: update google,cros-ec-pwm documentation

[Rob Herring]

On Thu, Apr 07, 2022 at 02:38:55PM +0000, Fabio Baltieri wrote:
> Hi Rob,
> 
> On Wed, Apr 06, 2022 at 10:41:45AM -0500, Rob Herring wrote:
> > On Thu, Mar 31, 2022 at 12:58:17PM +0000, Fabio Baltieri wrote:
> > > Update google,cros-ec-pwm node documentation to mention the
> > > google,use_pwm_type property.
> > > 
> > > Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
> > > ---
> > >  .../devicetree/bindings/pwm/google,cros-ec-pwm.yaml         | 6 ++++++
> > >  1 file changed, 6 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > > index 4cfbffd8414a..9c895c990ed8 100644
> > > --- a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > > +++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > > @@ -19,6 +19,12 @@ description: |
> > >  properties:
> > >    compatible:
> > >      const: google,cros-ec-pwm
> > > +
> > > +  google,use-pwm-type:
> > > +    description:
> > > +      Use PWM types (CROS_EC_PWM_DT_<...>) instead of generic channels.
> > > +    type: boolean
> > 
> > Either do a new compatible string if the cell interpretation is mutually 
> > exclusive (channel number vs. type) or split the number space for the 
> > 1st cell between type and channel number. IOW, set a bit (31?) to 
> > signify the number is a type, not a channel.
> 
> Split the number space was my first (tentative) implementation as well,
> but it turns out that the PWM subsystem really wants channels to be
> zero-based[1], so I don't think flags or bitmasks are really an option.

Fix the PWM subsystem then...

> New compatible sounds good though, I'll rework a v3 with that change.
> 
> Thanks!
> Fabio
> 
> [1] https://elixir.bootlin.com/linux/v5.17/source/drivers/pwm/core.c#L423
> 
> -- 
> Fabio Baltieri

Re: [PATCH v2 3/4] dt-bindings: update google,cros-ec-pwm documentation

[Fabio Baltieri]

On Thu, Apr 07, 2022 at 11:49:09AM -0500, Rob Herring wrote:
> On Thu, Apr 07, 2022 at 02:38:55PM +0000, Fabio Baltieri wrote:
> > Hi Rob,
> > 
> > On Wed, Apr 06, 2022 at 10:41:45AM -0500, Rob Herring wrote:
> > > On Thu, Mar 31, 2022 at 12:58:17PM +0000, Fabio Baltieri wrote:
> > > > Update google,cros-ec-pwm node documentation to mention the
> > > > google,use_pwm_type property.
> > > > 
> > > > Signed-off-by: Fabio Baltieri <fabiobaltieri@chromium.org>
> > > > ---
> > > >  .../devicetree/bindings/pwm/google,cros-ec-pwm.yaml         | 6 ++++++
> > > >  1 file changed, 6 insertions(+)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > > > index 4cfbffd8414a..9c895c990ed8 100644
> > > > --- a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > > > +++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.yaml
> > > > @@ -19,6 +19,12 @@ description: |
> > > >  properties:
> > > >    compatible:
> > > >      const: google,cros-ec-pwm
> > > > +
> > > > +  google,use-pwm-type:
> > > > +    description:
> > > > +      Use PWM types (CROS_EC_PWM_DT_<...>) instead of generic channels.
> > > > +    type: boolean
> > > 
> > > Either do a new compatible string if the cell interpretation is mutually 
> > > exclusive (channel number vs. type) or split the number space for the 
> > > 1st cell between type and channel number. IOW, set a bit (31?) to 
> > > signify the number is a type, not a channel.
> > 
> > Split the number space was my first (tentative) implementation as well,
> > but it turns out that the PWM subsystem really wants channels to be
> > zero-based[1], so I don't think flags or bitmasks are really an option.
> 
> Fix the PWM subsystem then...

It's a good design decision, allows for probe time validation and a good
debugfs interface, I'm happy to have this feature comply with it.

> 
> > New compatible sounds good though, I'll rework a v3 with that change.
> > 
> > Thanks!
> > Fabio
> > 
> > [1] https://elixir.bootlin.com/linux/v5.17/source/drivers/pwm/core.c#L423
> > 
> > -- 
> > Fabio Baltieri

-- 
Fabio Baltieri