[PATCH v5 0/2] leds: TI LP8864/LP8866 support

[PATCH v5 0/2] leds: TI LP8864/LP8866 support

[A. Sverdlin]

From: Alexander Sverdlin <alexander.sverdlin@siemens.com>

The series adds support for a family of Texas Instruments' automotive
high-efficiency LED drivers with boost controller. The four or six
high-precision current sinks support phase shifting that is automatically
adjusted based on the number of channels in use. LED brightness can be
controlled globally through the I2C interface or PWM input.

Add new DT bindings for ti,lp8864 to support all four software-compatible
devices:
- LP8864
- LP8864S
- LP8866
- LP8866S

Add leds class driver for these devices.

Alexander Sverdlin (2):
  dt-bindings: backlight: add TI LP8864/LP8866 LED-backlight drivers
  leds: lp8864: New driver

 .../bindings/leds/backlight/ti,lp8864.yaml    |  80 +++++
 MAINTAINERS                                   |   7 +
 drivers/leds/Kconfig                          |  12 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-lp8864.c                    | 296 ++++++++++++++++++
 5 files changed, 396 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml
 create mode 100644 drivers/leds/leds-lp8864.c

-- 
2.47.1

[PATCH v5 1/2] dt-bindings: backlight: add TI LP8864/LP8866 LED-backlight drivers

[A. Sverdlin]

From: Alexander Sverdlin <alexander.sverdlin@siemens.com>

Add bindings for Texas Instruments' LP8864/LP8866 LED-backlight drivers.
Note that multiple channels in these models are used for load-balancing and
brightness is controlled gobally, so from a user perspective it's only one
LED.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
---
v5: no changes
v4: no changes
v3: no changes
v2: ti,8860 has been decoupled from this series and converted to YAML separately

 .../bindings/leds/backlight/ti,lp8864.yaml    | 80 +++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml

diff --git a/Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml b/Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml
new file mode 100644
index 000000000000..d44232d462bd
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml
@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/ti,lp8864.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments - LP8864/LP8866 4/6-Channel LED Driver family
+
+maintainers:
+  - Andrew Davis <afd@ti.com>
+  - Alexander Sverdlin <alexander.sverdlin@siemens.com>
+
+description: |
+  LP8866-Q1, LP8866S-Q1, LP8864-Q1, LP8864S-Q1 are display LED-backlight drivers
+  with 4/6 channels. LED brightness can be controlled globally through the I2C
+  interface or PWM input.
+
+  For more product information please see the links below:
+    https://www.ti.com/product/LP8864-Q1
+    https://www.ti.com/product/LP8864S-Q1
+    https://www.ti.com/product/LP8866-Q1
+    https://www.ti.com/product/LP8866S-Q1
+
+properties:
+  compatible:
+    const: ti,lp8864
+
+  reg:
+    maxItems: 1
+    description: I2C slave address
+
+  enable-gpios:
+    maxItems: 1
+    description: GPIO pin to enable (active high) / disable the device
+
+  vled-supply:
+    description: LED supply
+
+  led:
+    type: object
+    $ref: common.yaml#
+    properties:
+      function: true
+      color: true
+      label: true
+      linux,default-trigger: true
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - led
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@3a {
+            compatible = "ti,lp8864";
+            reg = <0x3a>;
+            enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
+            vled-supply = <&vbatt>;
+
+            led {
+                function = LED_FUNCTION_BACKLIGHT;
+                color = <LED_COLOR_ID_WHITE>;
+                linux,default-trigger = "backlight";
+            };
+        };
+    };
+
+...
-- 
2.47.1

[PATCH v5 2/2] leds: lp8864: New driver

[A. Sverdlin]

From: Alexander Sverdlin <alexander.sverdlin@siemens.com>

Add driver for TI LP8864, LP8864S, LP8866 4/6 channel LED-backlight drivers
with I2C interface.

Link: https://www.ti.com/lit/gpn/lp8864-q1
Link: https://www.ti.com/lit/gpn/lp8864s-q1
Link: https://www.ti.com/lit/gpn/lp8866-q1
Link: https://www.ti.com/lit/gpn/lp8866s-q1
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
---
Changelog:
v5: fixed LP8864_LED_STATUS_WR_MASK definition
v4:
- better separated comments from register defines
- removed NULL from fault text arrays for two regs with odd-even structure
- changed HW fault printf from errors to warnings
- renamed "buf" -> "val"
- reflowed the code with up to 100 symbols per line
- added comments for 8<->16-bit linear scaling in set/get callbacks
- removed register names from error messages
v3:
- dropped lp8864_init(), REGCACHE_NONE, %pe in dev_err_probe(),
  i2c_set_clientdata()
- added devm_add_action_or_reset() return value check, dev_err_probe() after
  devm_regmap_init_i2c()
v2: no changes

 MAINTAINERS                |   7 +
 drivers/leds/Kconfig       |  12 ++
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-lp8864.c | 296 +++++++++++++++++++++++++++++++++++++
 4 files changed, 316 insertions(+)
 create mode 100644 drivers/leds/leds-lp8864.c

diff --git a/MAINTAINERS b/MAINTAINERS
index b332995b3350..d4268a3bbc5a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -23322,6 +23322,13 @@ S:	Supported
 F:	Documentation/devicetree/bindings/iio/dac/ti,dac7612.yaml
 F:	drivers/iio/dac/ti-dac7612.c
 
+TEXAS INSTRUMENTS' LB8864 LED BACKLIGHT DRIVER
+M:	Alexander Sverdlin <alexander.sverdlin@siemens.com>
+L:	linux-leds@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml
+F:	drivers/leds/leds-lp8864.c
+
 TEXAS INSTRUMENTS' SYSTEM CONTROL INTERFACE (TISCI) PROTOCOL DRIVER
 M:	Nishanth Menon <nm@ti.com>
 M:	Tero Kristo <kristo@kernel.org>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 3bf51a4e01d7..5dde8f46100c 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -513,6 +513,18 @@ config LEDS_LP8860
 	  on the LP8860 4 channel LED driver using the I2C communication
 	  bus.
 
+config LEDS_LP8864
+	tristate "LED support for the TI LP8864/LP8866 4/6 channel LED drivers"
+	depends on LEDS_CLASS && I2C && OF
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for the TI LP8864-Q1,
+	  LP8864S-Q1, LP8866-Q1, LP8866S-Q1 4/6 channel LED backlight
+	  drivers with I2C interface.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called leds-lp8864.
+
 config LEDS_CLEVO_MAIL
 	tristate "Mail LED on Clevo notebook"
 	depends on LEDS_CLASS && BROKEN
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index e7982938ddc1..8a2caa48343b 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_LEDS_LP55XX_COMMON)	+= leds-lp55xx-common.o
 obj-$(CONFIG_LEDS_LP8501)		+= leds-lp8501.o
 obj-$(CONFIG_LEDS_LP8788)		+= leds-lp8788.o
 obj-$(CONFIG_LEDS_LP8860)		+= leds-lp8860.o
+obj-$(CONFIG_LEDS_LP8864)		+= leds-lp8864.o
 obj-$(CONFIG_LEDS_LT3593)		+= leds-lt3593.o
 obj-$(CONFIG_LEDS_MAX5970)		+= leds-max5970.o
 obj-$(CONFIG_LEDS_MAX77650)		+= leds-max77650.o
diff --git a/drivers/leds/leds-lp8864.c b/drivers/leds/leds-lp8864.c
new file mode 100644
index 000000000000..9ee9e5e0df3c
--- /dev/null
+++ b/drivers/leds/leds-lp8864.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * TI LP8864/LP8866 4/6 Channel LED Driver
+ *
+ * Copyright (C) 2024 Siemens AG
+ *
+ * Based on LP8860 driver by Dan Murphy <dmurphy@ti.com>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#define LP8864_BRT_CONTROL		0x00
+#define LP8864_USER_CONFIG1		0x04
+#define   LP8864_BRT_MODE_MASK		GENMASK(9, 8)
+#define   LP8864_BRT_MODE_REG		BIT(9)		/* Brightness control by DISPLAY_BRT reg */
+#define LP8864_SUPPLY_STATUS		0x0e
+#define LP8864_BOOST_STATUS		0x10
+#define LP8864_LED_STATUS		0x12
+#define   LP8864_LED_STATUS_WR_MASK	GENMASK(14, 9)	/* Writeable bits in the LED_STATUS reg */
+
+/* Textual meaning for status bits, starting from bit 1 */
+static const char *const lp8864_supply_status_msg[] = {
+	"Vin under-voltage fault",
+	"Vin over-voltage fault",
+	"Vdd under-voltage fault",
+	"Vin over-current fault",
+	"Missing charge pump fault",
+	"Charge pump fault",
+	"Missing boost sync fault",
+	"CRC error fault ",
+};
+
+/* Textual meaning for status bits, starting from bit 1 */
+static const char *const lp8864_boost_status_msg[] = {
+	"Boost OVP low fault",
+	"Boost OVP high fault",
+	"Boost over-current fault",
+	"Missing boost FSET resistor fault",
+	"Missing MODE SEL resistor fault",
+	"Missing LED resistor fault",
+	"ISET resistor short to ground fault",
+	"Thermal shutdown fault",
+};
+
+/* Textual meaning for every register bit */
+static const char *const lp8864_led_status_msg[] = {
+	"LED 1 fault",
+	"LED 2 fault",
+	"LED 3 fault",
+	"LED 4 fault",
+	"LED 5 fault",
+	"LED 6 fault",
+	"LED open fault",
+	"LED internal short fault",
+	"LED short to GND fault",
+	NULL, NULL, NULL,
+	"Invalid string configuration fault",
+	NULL,
+	"I2C time out fault",
+};
+
+/**
+ * struct lp8864_led
+ * @client: Pointer to the I2C client
+ * @led_dev: led class device pointer
+ * @regmap: Devices register map
+ * @led_status_mask: Helps to report LED fault only once
+ */
+struct lp8864_led {
+	struct i2c_client *client;
+	struct led_classdev led_dev;
+	struct regmap *regmap;
+	u16 led_status_mask;
+};
+
+static int lp8864_fault_check(struct lp8864_led *led)
+{
+	int ret, i;
+	unsigned int val;
+
+	ret = regmap_read(led->regmap, LP8864_SUPPLY_STATUS, &val);
+	if (ret)
+		goto err;
+
+	/* Odd bits are status bits, even bits are clear bits */
+	for (i = 0; i < ARRAY_SIZE(lp8864_supply_status_msg); i++)
+		if (val & BIT(i * 2 + 1))
+			dev_warn(&led->client->dev, "%s\n", lp8864_supply_status_msg[i]);
+
+	/*
+	 * Clear bits have an index preceding the corresponding Status bits;
+	 * both have to be written "1" simultaneously to clear the corresponding
+	 * Status bit.
+	 */
+	if (val)
+		ret = regmap_write(led->regmap, LP8864_SUPPLY_STATUS, val >> 1 | val);
+	if (ret)
+		goto err;
+
+	ret = regmap_read(led->regmap, LP8864_BOOST_STATUS, &val);
+	if (ret)
+		goto err;
+
+	/* Odd bits are status bits, even bits are clear bits */
+	for (i = 0; i < ARRAY_SIZE(lp8864_boost_status_msg); i++)
+		if (val & BIT(i * 2 + 1))
+			dev_warn(&led->client->dev, "%s\n", lp8864_boost_status_msg[i]);
+
+	if (val)
+		ret = regmap_write(led->regmap, LP8864_BOOST_STATUS, val >> 1 | val);
+	if (ret)
+		goto err;
+
+	ret = regmap_read(led->regmap, LP8864_LED_STATUS, &val);
+	if (ret)
+		goto err;
+
+	/*
+	 * Clear already reported faults that maintain their value until device
+	 * power-down
+	 */
+	val &= ~led->led_status_mask;
+
+	for (i = 0; i < ARRAY_SIZE(lp8864_led_status_msg); i++)
+		if (lp8864_led_status_msg[i] && val & BIT(i))
+			dev_warn(&led->client->dev, "%s\n", lp8864_led_status_msg[i]);
+
+	/*
+	 * Mark those which maintain their value until device power-down as
+	 * "already reported"
+	 */
+	led->led_status_mask |= val & ~LP8864_LED_STATUS_WR_MASK;
+
+	/*
+	 * Only bits 14, 12, 10 have to be cleared here, but others are RO,
+	 * we don't care what we write to them.
+	 */
+	if (val & LP8864_LED_STATUS_WR_MASK)
+		ret = regmap_write(led->regmap, LP8864_LED_STATUS, val >> 1 | val);
+	if (ret)
+		goto err;
+
+	return 0;
+
+err:
+	dev_err(&led->client->dev, "Failed to read/clear faults (%pe)\n", ERR_PTR(ret));
+
+	return ret;
+}
+
+static int lp8864_brightness_set(struct led_classdev *led_cdev,
+				 enum led_brightness brt_val)
+{
+	struct lp8864_led *led = container_of(led_cdev, struct lp8864_led, led_dev);
+	/* Scale 0..LED_FULL into 16-bit HW brightness */
+	unsigned int val = brt_val * 0xffff / LED_FULL;
+	int ret;
+
+	ret = lp8864_fault_check(led);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(led->regmap, LP8864_BRT_CONTROL, val);
+	if (ret)
+		dev_err(&led->client->dev, "Failed to write brightness value\n");
+
+	return ret;
+}
+
+static enum led_brightness lp8864_brightness_get(struct led_classdev *led_cdev)
+{
+	struct lp8864_led *led = container_of(led_cdev, struct lp8864_led, led_dev);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(led->regmap, LP8864_BRT_CONTROL, &val);
+	if (ret) {
+		dev_err(&led->client->dev, "Failed to read brightness value\n");
+		return ret;
+	}
+
+	/* Scale 16-bit HW brightness into 0..LED_FULL */
+	return val * LED_FULL / 0xffff;
+}
+
+static const struct regmap_config lp8864_regmap_config = {
+	.reg_bits		= 8,
+	.val_bits		= 16,
+	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
+};
+
+static void lp8864_disable_gpio(void *data)
+{
+	struct gpio_desc *gpio = data;
+
+	gpiod_set_value(gpio, 0);
+}
+
+static int lp8864_probe(struct i2c_client *client)
+{
+	int ret;
+	struct lp8864_led *led;
+	struct device_node *np = dev_of_node(&client->dev);
+	struct device_node *child_node;
+	struct led_init_data init_data = {};
+	struct gpio_desc *enable_gpio;
+
+	led = devm_kzalloc(&client->dev, sizeof(*led), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+
+	child_node = of_get_next_available_child(np, NULL);
+	if (!child_node) {
+		dev_err(&client->dev, "No LED function defined\n");
+		return -EINVAL;
+	}
+
+	ret = devm_regulator_get_enable_optional(&client->dev, "vled");
+	if (ret && ret != -ENODEV)
+		return dev_err_probe(&client->dev, ret, "Failed to enable vled regulator\n");
+
+	enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(enable_gpio))
+		return dev_err_probe(&client->dev, PTR_ERR(enable_gpio),
+				     "Failed to get enable GPIO\n");
+
+	ret = devm_add_action_or_reset(&client->dev, lp8864_disable_gpio, enable_gpio);
+	if (ret)
+		return ret;
+
+	led->client = client;
+	led->led_dev.brightness_set_blocking = lp8864_brightness_set;
+	led->led_dev.brightness_get = lp8864_brightness_get;
+
+	led->regmap = devm_regmap_init_i2c(client, &lp8864_regmap_config);
+	if (IS_ERR(led->regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(led->regmap),
+				     "Failed to allocate regmap\n");
+
+	/* Control brightness by DISPLAY_BRT register */
+	ret = regmap_update_bits(led->regmap, LP8864_USER_CONFIG1, LP8864_BRT_MODE_MASK,
+								   LP8864_BRT_MODE_REG);
+	if (ret) {
+		dev_err(&led->client->dev, "Failed to set brightness control mode\n");
+		return ret;
+	}
+
+	ret = lp8864_fault_check(led);
+	if (ret)
+		return ret;
+
+	init_data.fwnode = of_fwnode_handle(child_node);
+	init_data.devicename = "lp8864";
+	init_data.default_label = ":display_cluster";
+
+	ret = devm_led_classdev_register_ext(&client->dev, &led->led_dev, &init_data);
+	if (ret)
+		dev_err(&client->dev, "Failed to register LED device (%pe)\n", ERR_PTR(ret));
+
+	return ret;
+}
+
+static const struct i2c_device_id lp8864_id[] = {
+	{ "lp8864" },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, lp8864_id);
+
+static const struct of_device_id of_lp8864_leds_match[] = {
+	{ .compatible = "ti,lp8864" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_lp8864_leds_match);
+
+static struct i2c_driver lp8864_driver = {
+	.driver = {
+		.name	= "lp8864",
+		.of_match_table = of_lp8864_leds_match,
+	},
+	.probe		= lp8864_probe,
+	.id_table	= lp8864_id,
+};
+module_i2c_driver(lp8864_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LP8864/LP8866 LED driver");
+MODULE_AUTHOR("Alexander Sverdlin <alexander.sverdlin@siemens.com>");
+MODULE_LICENSE("GPL");
-- 
2.47.1

Re: (subset) [PATCH v5 2/2] leds: lp8864: New driver

[Lee Jones]

On Wed, 18 Dec 2024 22:08:27 +0100, A. Sverdlin wrote:
> Add driver for TI LP8864, LP8864S, LP8866 4/6 channel LED-backlight drivers
> with I2C interface.
> 
> 

Applied, thanks!

[2/2] leds: lp8864: New driver
      commit: e14d879292b0f7755c0d51b82a19b30859bb080a

--
Lee Jones [李琼斯]

Re: [PATCH v5 1/2] dt-bindings: backlight: add TI LP8864/LP8866 LED-backlight drivers

[Rob Herring]

On Wed, Dec 18, 2024 at 10:08:26PM +0100, A. Sverdlin wrote:
> From: Alexander Sverdlin <alexander.sverdlin@siemens.com>
> 
> Add bindings for Texas Instruments' LP8864/LP8866 LED-backlight drivers.
> Note that multiple channels in these models are used for load-balancing and
> brightness is controlled gobally, so from a user perspective it's only one
> LED.
> 
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
> ---
> v5: no changes
> v4: no changes
> v3: no changes
> v2: ti,8860 has been decoupled from this series and converted to YAML separately
> 
>  .../bindings/leds/backlight/ti,lp8864.yaml    | 80 +++++++++++++++++++
>  1 file changed, 80 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/backlight/ti,lp8864.yaml

Applied as it seems this was missed by Lee.

In the future, you can resend without my ack/review tag and ask me to 
apply if something gets missed.

Rob