[PATCH v5 0/3] Add support for the TLC5925

[PATCH v5 0/3] Add support for the TLC5925

[Jean-Jacques Hiblot]

This series adds the support for the TLC5925 LED controller.
This LED controller is driven through SPI. There is little internal logic
and it can be thought of as a deserializer + latches.
The TLC5925 itself drives up to 16 LEDs, but multiple TLC5925s can be
chained to drive more.

The first patch describes the dt bindings.
The second patch implements most of the driver and supports only
synchronous brightness setting (brightness_set_blocking).
The last patch implements the non-blocking version (brightness_set).

changes v4->v5:
 * add the headers that the code is a direct user of
 * replace dev_err() with dev_err_probe() in ->probe()
 * comestic changes (spaces, alignment and blank lines)

changes v3->v4:
 * add missing MODULE_DEVICE_TABLE(of, ...) 
 * use dev_err_probe() to avoid spamming the log in case of deferred probe
 * use bitmap ops instead of direct memory access + lock
 * sort headers and a few other cosmetic changes.

changes v2->v3:
 * fixed the yaml description of the bindings (now passes dt_binding_check)
 * renamed shit-register-length into ti,shift-register-length and specify
   its type

changes v1->v2:
 * renamed property shift_register_length into shift-register-length
 * add a SPI MODULE_DEVICE_TABLE structure
 * fixed the yaml description of the bindings (now passes dt_binding_check)

Jean-Jacques Hiblot (3):
  dt-bindings: leds: Add bindings for the TLC5925 controller
  leds: Add driver for the TLC5925 LED controller
  leds: tlc5925: Add support for non blocking operations

 .../devicetree/bindings/leds/ti,tlc5925.yaml  | 107 +++++++++++
 drivers/leds/Kconfig                          |   6 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-tlc5925.c                   | 181 ++++++++++++++++++
 4 files changed, 295 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
 create mode 100644 drivers/leds/leds-tlc5925.c

-- 
2.25.1

[PATCH v5 1/3] dt-bindings: leds: Add bindings for the TLC5925 controller

[Jean-Jacques Hiblot]

Add bindings documentation for the TLC5925 LED controller.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
---
 .../devicetree/bindings/leds/ti,tlc5925.yaml  | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/ti,tlc5925.yaml

diff --git a/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
new file mode 100644
index 000000000000..12a71e48f854
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
@@ -0,0 +1,107 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/ti,tlc5925.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LEDs connected to TI TLC5925 controller
+
+maintainers:
+  - Jean-Jacques Hiblot <jjhiblot@traphandler.com>
+
+description: |
+  The TLC5925 is a low-power 16-channel constant-current LED sink driver.
+  It is controlled through a SPI interface.
+  It is built around a shift register and latches which convert serial
+  input data into a parallel output. Several TLC5925 can be chained to
+  control more than 16 LEDs with a single chip-select.
+  The brightness level cannot be controlled, each LED is either on or off.
+
+  Each LED is represented as a sub-node of the ti,tlc5925 device.
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    const: ti,tlc5925
+
+  ti,shift-register-length:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 8
+    description: |
+      The length of the shift register. If several TLC5925 are chained,
+      shift_register_length should be set to 16 times the number of TLC5925.
+      The value must be a multiple of 8.
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  output-enable-b-gpios:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description: |
+      Optional GPIO pins to enable/disable the parallel output. They describe
+      the GPIOs connected to the OE/ pin of the TLC5925s.
+
+patternProperties:
+  "@[0-9a-f]+$":
+    type: object
+    $ref: common.yaml#
+
+    properties:
+      reg:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: |
+          LED pin number (must be lower than ti,shift-register-length).
+          The furthest LED down the chain has the pin number 0.
+
+    required:
+      - reg
+
+required:
+  - "#address-cells"
+  - "#size-cells"
+  - ti,shift-register-length
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        leds@2 {
+            compatible = "ti,tlc5925";
+            reg = <0x02>;
+            spi-max-frequency = <30000000>;
+            ti,shift-register-length = <32>;
+            output-enable-b-gpios = <&gpio0b 9 GPIO_ACTIVE_HIGH>, <&gpio0b 7 GPIO_ACTIVE_HIGH>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            led@0 {
+                reg = <0>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_GREEN>;
+            };
+
+            led@4 {
+                reg = <4>;
+                function = LED_FUNCTION_STATUS;
+                color = <LED_COLOR_ID_RED>;
+            };
+
+            led@1f {
+                reg = <31>;
+                function = LED_FUNCTION_PANIC;
+                color = <LED_COLOR_ID_RED>;
+            };
+        };
+
+    };
-- 
2.25.1

[PATCH v5 2/3] leds: Add driver for the TLC5925 LED controller

[Jean-Jacques Hiblot]

The TLC5925 is a 16-channels constant-current LED sink driver.
It is controlled via SPI but doesn't offer a register-based interface.
Instead it contains a shift register and latches that convert the
serial input into a parallel output.

Datasheet: https://www.ti.com/lit/ds/symlink/tlc5925.pdf
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
---
 drivers/leds/Kconfig        |   6 ++
 drivers/leds/Makefile       |   1 +
 drivers/leds/leds-tlc5925.c | 147 ++++++++++++++++++++++++++++++++++++
 3 files changed, 154 insertions(+)
 create mode 100644 drivers/leds/leds-tlc5925.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a49979f41eee..b17eb01210ba 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -658,6 +658,12 @@ config LEDS_TLC591XX
 	  This option enables support for Texas Instruments TLC59108
 	  and TLC59116 LED controllers.
 
+config LEDS_TLC5925
+	tristate "LED driver for TLC5925 controller"
+	depends on LEDS_CLASS && SPI
+	help
+	  This option enables support for Texas Instruments TLC5925.
+
 config LEDS_MAX77650
 	tristate "LED support for Maxim MAX77650 PMIC"
 	depends on LEDS_CLASS && MFD_MAX77650
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 4fd2f92cd198..9d15b88d482f 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_LEDS_SYSCON)		+= leds-syscon.o
 obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
 obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
 obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
+obj-$(CONFIG_LEDS_TLC5925)		+= leds-tlc5925.o
 obj-$(CONFIG_LEDS_TPS6105X)		+= leds-tps6105x.o
 obj-$(CONFIG_LEDS_TURRIS_OMNIA)		+= leds-turris-omnia.o
 obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
diff --git a/drivers/leds/leds-tlc5925.c b/drivers/leds/leds-tlc5925.c
new file mode 100644
index 000000000000..2fb91d9767aa
--- /dev/null
+++ b/drivers/leds/leds-tlc5925.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * The driver supports controllers with a very simple SPI protocol:
+ * - the data is deserialized in a shift-register when CS is asserted
+ * - the data is latched when CS is de-asserted
+ * - the LED are either on or off (no control of the brightness)
+ *
+ * Supported devices:
+ * - "ti,tlc5925":  Low-Power 16-Channel Constant-Current LED Sink Driver
+ *                  https://www.ti.com/lit/ds/symlink/tlc5925.pdf
+ */
+
+#include <linux/container_of.h>
+#include <linux/err.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/types.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio/consumer.h>
+
+struct single_led_priv {
+	struct led_classdev cdev;
+	int idx;
+};
+
+struct tlc5925_leds_priv {
+	int max_num_leds;
+	unsigned long *state;
+	struct single_led_priv leds[];
+};
+
+static int tlc5925_brightness_set_blocking(struct led_classdev *cdev,
+					    enum led_brightness brightness)
+{
+	struct spi_device *spi = to_spi_device(cdev->dev->parent);
+	struct tlc5925_leds_priv *priv = spi_get_drvdata(spi);
+	struct single_led_priv *led =
+		container_of(cdev, struct single_led_priv, cdev);
+	int index = led->idx;
+
+	assign_bit(index, priv->state, !!brightness);
+
+	return spi_write(spi, priv->state, BITS_TO_BYTES(priv->max_num_leds));
+}
+
+static int tlc5925_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct fwnode_handle *child;
+	struct tlc5925_leds_priv *priv;
+	int ret;
+	int max_num_leds, count;
+	struct gpio_descs *gpios;
+
+	/* Assert all the OE/ lines */
+	gpios = devm_gpiod_get_array(dev, "output-enable-b", GPIOD_OUT_LOW);
+	if (IS_ERR(gpios))
+		return dev_err_probe(dev, PTR_ERR(gpios),
+			      "Unable to get the 'output-enable-b' gpios\n");
+
+	count = device_get_child_node_count(dev);
+	if (!count)
+		return dev_err_probe(dev, -ENODEV, "no led defined.\n");
+
+	ret = device_property_read_u32(dev, "ti,shift-register-length",
+					     &max_num_leds);
+	if (ret)
+		return dev_err_probe(dev, -EINVAL,
+				     "'ti,shift-register-length' property is required.\n");
+	if (max_num_leds % 8)
+		return dev_err_probe(dev, -EINVAL,
+				     "'ti,shift-register-length' must be a multiple of 8\n");
+	if (max_num_leds == 0)
+		return dev_err_probe(dev, -EINVAL,
+				     "'ti,shift-register-length' must be greater than 0\n");
+
+	priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->state = devm_bitmap_zalloc(dev, max_num_leds, GFP_KERNEL);
+	if (!priv->state)
+		return -ENOMEM;
+
+	priv->max_num_leds = max_num_leds;
+
+	device_for_each_child_node(dev, child) {
+		struct led_init_data init_data = { .fwnode = child };
+		struct led_classdev *cdev;
+		u32 idx;
+
+		ret = fwnode_property_read_u32(child, "reg", &idx);
+		if (ret || idx >= max_num_leds) {
+			dev_warn(dev, "%pfwP: invalid reg value. Ignoring.\n",
+				 child);
+			fwnode_handle_put(child);
+			continue;
+		}
+
+		count--;
+		priv->leds[count].idx = idx;
+		cdev = &(priv->leds[count].cdev);
+		cdev->brightness = LED_OFF;
+		cdev->max_brightness = 1;
+		cdev->brightness_set_blocking = tlc5925_brightness_set_blocking;
+
+		ret = devm_led_classdev_register_ext(dev, cdev, &init_data);
+		if (ret) {
+			dev_warn(dev, "%pfwP: cannot create LED device.\n",
+				child);
+			fwnode_handle_put(child);
+			continue;
+		}
+	}
+
+	spi_set_drvdata(spi, priv);
+
+	return 0;
+}
+
+static const struct of_device_id tlc5925_dt_ids[] = {
+	{ .compatible = "ti,tlc5925", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tlc5925_dt_ids);
+
+static const struct spi_device_id tlc5925_id[] = {
+	{"tlc5925", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, tlc5925_id);
+
+static struct spi_driver tlc5925_driver = {
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= tlc5925_dt_ids,
+	},
+	.id_table = tlc5925_id,
+	.probe = tlc5925_probe,
+};
+module_spi_driver(tlc5925_driver);
+
+MODULE_AUTHOR("Jean-Jacques Hiblot <jjhiblot@traphandler.com>");
+MODULE_DESCRIPTION("TLC5925 LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:tlc5925");
-- 
2.25.1

[PATCH v5 3/3] leds: tlc5925: Add support for non blocking operations

[Jean-Jacques Hiblot]

Settings multiple LEDs in a row can be a slow operation because of the
time required to acquire the bus and prepare the transfer.
And, in most cases, it is not required that the operation is synchronous.
Implementing the non-blocking brightness_set() for such cases.
A work queue is used to perform the actual SPI transfer.

The blocking method is still available in case someone needs to perform
this operation synchronously (ie by calling led_set_brightness_sync()).

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
---
 drivers/leds/leds-tlc5925.c | 38 +++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/leds-tlc5925.c b/drivers/leds/leds-tlc5925.c
index 2fb91d9767aa..786497c84ca4 100644
--- a/drivers/leds/leds-tlc5925.c
+++ b/drivers/leds/leds-tlc5925.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/types.h>
+#include <linux/workqueue.h>
 #include <linux/spi/spi.h>
 #include <linux/gpio/consumer.h>
 
@@ -27,10 +28,25 @@ struct single_led_priv {
 struct tlc5925_leds_priv {
 	int max_num_leds;
 	unsigned long *state;
+	struct spi_device *spi;
+	struct work_struct xmit_work;
 	struct single_led_priv leds[];
 };
 
-static int tlc5925_brightness_set_blocking(struct led_classdev *cdev,
+static int xmit(struct tlc5925_leds_priv *priv)
+{
+	return spi_write(priv->spi, priv->state, BITS_TO_BYTES(priv->max_num_leds));
+}
+
+static void xmit_work(struct work_struct *ws)
+{
+	struct tlc5925_leds_priv *priv =
+		container_of(ws, struct tlc5925_leds_priv, xmit_work);
+
+	xmit(priv);
+};
+
+static void tlc5925_brightness_set(struct led_classdev *cdev,
 					    enum led_brightness brightness)
 {
 	struct spi_device *spi = to_spi_device(cdev->dev->parent);
@@ -41,9 +57,23 @@ static int tlc5925_brightness_set_blocking(struct led_classdev *cdev,
 
 	assign_bit(index, priv->state, !!brightness);
 
-	return spi_write(spi, priv->state, BITS_TO_BYTES(priv->max_num_leds));
+	schedule_work(&priv->xmit_work);
 }
 
+static int tlc5925_brightness_set_blocking(struct led_classdev *cdev,
+					    enum led_brightness brightness)
+{
+	struct spi_device *spi = to_spi_device(cdev->dev->parent);
+	struct tlc5925_leds_priv *priv = spi_get_drvdata(spi);
+	struct single_led_priv *led =
+		container_of(cdev, struct single_led_priv, cdev);
+	int index = led->idx;
+
+	assign_bit(index, priv->state, !!brightness);
+
+	cancel_work_sync(&priv->xmit_work);
+	return xmit(priv);
+}
 static int tlc5925_probe(struct spi_device *spi)
 {
 	struct device *dev = &spi->dev;
@@ -83,6 +113,9 @@ static int tlc5925_probe(struct spi_device *spi)
 	if (!priv->state)
 		return -ENOMEM;
 
+	priv->spi = spi;
+	INIT_WORK(&priv->xmit_work, xmit_work);
+
 	priv->max_num_leds = max_num_leds;
 
 	device_for_each_child_node(dev, child) {
@@ -103,6 +136,7 @@ static int tlc5925_probe(struct spi_device *spi)
 		cdev = &(priv->leds[count].cdev);
 		cdev->brightness = LED_OFF;
 		cdev->max_brightness = 1;
+		cdev->brightness_set = tlc5925_brightness_set;
 		cdev->brightness_set_blocking = tlc5925_brightness_set_blocking;
 
 		ret = devm_led_classdev_register_ext(dev, cdev, &init_data);
-- 
2.25.1

Re: [PATCH v5 0/3] Add support for the TLC5925

[Andy Shevchenko]

On Tue, Jun 14, 2022 at 5:42 PM Jean-Jacques Hiblot
<jjhiblot@traphandler.com> wrote:
>
> This series adds the support for the TLC5925 LED controller.
> This LED controller is driven through SPI. There is little internal logic
> and it can be thought of as a deserializer + latches.
> The TLC5925 itself drives up to 16 LEDs, but multiple TLC5925s can be
> chained to drive more.
>
> The first patch describes the dt bindings.
> The second patch implements most of the driver and supports only
> synchronous brightness setting (brightness_set_blocking).
> The last patch implements the non-blocking version (brightness_set).

Thanks!

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
for the entire series.

You may (if v6 is needed) to keep headers ordered (like gpio/consumer
as G and workqueue as W in alphabet).

> changes v4->v5:
>  * add the headers that the code is a direct user of
>  * replace dev_err() with dev_err_probe() in ->probe()
>  * comestic changes (spaces, alignment and blank lines)
>
> changes v3->v4:
>  * add missing MODULE_DEVICE_TABLE(of, ...)
>  * use dev_err_probe() to avoid spamming the log in case of deferred probe
>  * use bitmap ops instead of direct memory access + lock
>  * sort headers and a few other cosmetic changes.
>
> changes v2->v3:
>  * fixed the yaml description of the bindings (now passes dt_binding_check)
>  * renamed shit-register-length into ti,shift-register-length and specify
>    its type
>
> changes v1->v2:
>  * renamed property shift_register_length into shift-register-length
>  * add a SPI MODULE_DEVICE_TABLE structure
>  * fixed the yaml description of the bindings (now passes dt_binding_check)
>
> Jean-Jacques Hiblot (3):
>   dt-bindings: leds: Add bindings for the TLC5925 controller
>   leds: Add driver for the TLC5925 LED controller
>   leds: tlc5925: Add support for non blocking operations
>
>  .../devicetree/bindings/leds/ti,tlc5925.yaml  | 107 +++++++++++
>  drivers/leds/Kconfig                          |   6 +
>  drivers/leds/Makefile                         |   1 +
>  drivers/leds/leds-tlc5925.c                   | 181 ++++++++++++++++++
>  4 files changed, 295 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
>  create mode 100644 drivers/leds/leds-tlc5925.c
>
> --
> 2.25.1
>


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 1/3] dt-bindings: leds: Add bindings for the TLC5925 controller

[Rob Herring]

On Tue, Jun 14, 2022 at 05:42:43PM +0200, Jean-Jacques Hiblot wrote:
> Add bindings documentation for the TLC5925 LED controller.
> 
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> ---
>  .../devicetree/bindings/leds/ti,tlc5925.yaml  | 107 ++++++++++++++++++
>  1 file changed, 107 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
> new file mode 100644
> index 000000000000..12a71e48f854
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
> @@ -0,0 +1,107 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/ti,tlc5925.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: LEDs connected to TI TLC5925 controller
> +
> +maintainers:
> +  - Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> +
> +description: |
> +  The TLC5925 is a low-power 16-channel constant-current LED sink driver.
> +  It is controlled through a SPI interface.
> +  It is built around a shift register and latches which convert serial
> +  input data into a parallel output. Several TLC5925 can be chained to
> +  control more than 16 LEDs with a single chip-select.
> +  The brightness level cannot be controlled, each LED is either on or off.
> +
> +  Each LED is represented as a sub-node of the ti,tlc5925 device.
> +
> +$ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +properties:
> +  compatible:
> +    const: ti,tlc5925
> +
> +  ti,shift-register-length:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    minimum: 8
> +    description: |

Don't need '|' if no formatting to preserve.

> +      The length of the shift register. If several TLC5925 are chained,
> +      shift_register_length should be set to 16 times the number of TLC5925.
> +      The value must be a multiple of 8.

multipleOf: 8

Though I'm confused why it's not 16.

> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +  output-enable-b-gpios:
> +    $ref: /schemas/types.yaml#/definitions/phandle-array

Already has a type.

> +    description: |
> +      Optional GPIO pins to enable/disable the parallel output. They describe
> +      the GPIOs connected to the OE/ pin of the TLC5925s.
> +
> +patternProperties:
> +  "@[0-9a-f]+$":
> +    type: object
> +    $ref: common.yaml#

       unevaluatedProperties: false

> +
> +    properties:
> +      reg:
> +        $ref: /schemas/types.yaml#/definitions/uint32

Don't need a type here.

> +        description: |
> +          LED pin number (must be lower than ti,shift-register-length).
> +          The furthest LED down the chain has the pin number 0.
> +
> +    required:
> +      - reg
> +
> +required:
> +  - "#address-cells"
> +  - "#size-cells"
> +  - ti,shift-register-length

Is there not a default when not chained? 

> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/leds/common.h>
> +
> +    spi0 {

spi {

> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        leds@2 {
> +            compatible = "ti,tlc5925";
> +            reg = <0x02>;
> +            spi-max-frequency = <30000000>;
> +            ti,shift-register-length = <32>;
> +            output-enable-b-gpios = <&gpio0b 9 GPIO_ACTIVE_HIGH>, <&gpio0b 7 GPIO_ACTIVE_HIGH>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            led@0 {
> +                reg = <0>;
> +                function = LED_FUNCTION_STATUS;
> +                color = <LED_COLOR_ID_GREEN>;
> +            };
> +
> +            led@4 {
> +                reg = <4>;
> +                function = LED_FUNCTION_STATUS;
> +                color = <LED_COLOR_ID_RED>;
> +            };
> +
> +            led@1f {
> +                reg = <31>;
> +                function = LED_FUNCTION_PANIC;
> +                color = <LED_COLOR_ID_RED>;
> +            };
> +        };
> +
> +    };
> -- 
> 2.25.1
> 
> 

Re: [PATCH v5 1/3] dt-bindings: leds: Add bindings for the TLC5925 controller

[Jean-Jacques Hiblot]

On 18/06/2022 01:19, Rob Herring wrote:
> On Tue, Jun 14, 2022 at 05:42:43PM +0200, Jean-Jacques Hiblot wrote:
>> Add bindings documentation for the TLC5925 LED controller.
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
>> ---
>>   .../devicetree/bindings/leds/ti,tlc5925.yaml  | 107 ++++++++++++++++++
>>   1 file changed, 107 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
>> new file mode 100644
>> index 000000000000..12a71e48f854
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml
>> @@ -0,0 +1,107 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/ti,tlc5925.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: LEDs connected to TI TLC5925 controller
>> +
>> +maintainers:
>> +  - Jean-Jacques Hiblot <jjhiblot@traphandler.com>
>> +
>> +description: |
>> +  The TLC5925 is a low-power 16-channel constant-current LED sink driver.
>> +  It is controlled through a SPI interface.
>> +  It is built around a shift register and latches which convert serial
>> +  input data into a parallel output. Several TLC5925 can be chained to
>> +  control more than 16 LEDs with a single chip-select.
>> +  The brightness level cannot be controlled, each LED is either on or off.
>> +
>> +  Each LED is represented as a sub-node of the ti,tlc5925 device.
>> +
>> +$ref: /schemas/spi/spi-peripheral-props.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    const: ti,tlc5925
>> +
>> +  ti,shift-register-length:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    minimum: 8
>> +    description: |
> Don't need '|' if no formatting to preserve.
>
>> +      The length of the shift register. If several TLC5925 are chained,
>> +      shift_register_length should be set to 16 times the number of TLC5925.
>> +      The value must be a multiple of 8.
> multipleOf: 8
>
> Though I'm confused why it's not 16.

The reason why it is 8 instead of 16, is that there exists other LEDs 
controllers that are compatible with this driver and use only a 8-bits 
shift register.

The main reason is that the granularity of the size of a SPI transfer is 
8 bits.

>> +
>> +  "#address-cells":
>> +    const: 1
>> +
>> +  "#size-cells":
>> +    const: 0
>> +
>> +  output-enable-b-gpios:
>> +    $ref: /schemas/types.yaml#/definitions/phandle-array
> Already has a type.
>
>> +    description: |
>> +      Optional GPIO pins to enable/disable the parallel output. They describe
>> +      the GPIOs connected to the OE/ pin of the TLC5925s.
>> +
>> +patternProperties:
>> +  "@[0-9a-f]+$":
>> +    type: object
>> +    $ref: common.yaml#
>         unevaluatedProperties: false
>
>> +
>> +    properties:
>> +      reg:
>> +        $ref: /schemas/types.yaml#/definitions/uint32
> Don't need a type here.
>
>> +        description: |
>> +          LED pin number (must be lower than ti,shift-register-length).
>> +          The furthest LED down the chain has the pin number 0.
>> +
>> +    required:
>> +      - reg
>> +
>> +required:
>> +  - "#address-cells"
>> +  - "#size-cells"
>> +  - ti,shift-register-length
> Is there not a default when not chained?

A default value could be used indeed. I'll rework the driver to use a 
default value of 16

Thanks

Jean-Jacques

>
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +    #include <dt-bindings/leds/common.h>
>> +
>> +    spi0 {
> spi {
>
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        leds@2 {
>> +            compatible = "ti,tlc5925";
>> +            reg = <0x02>;
>> +            spi-max-frequency = <30000000>;
>> +            ti,shift-register-length = <32>;
>> +            output-enable-b-gpios = <&gpio0b 9 GPIO_ACTIVE_HIGH>, <&gpio0b 7 GPIO_ACTIVE_HIGH>;
>> +            #address-cells = <1>;
>> +            #size-cells = <0>;
>> +
>> +            led@0 {
>> +                reg = <0>;
>> +                function = LED_FUNCTION_STATUS;
>> +                color = <LED_COLOR_ID_GREEN>;
>> +            };
>> +
>> +            led@4 {
>> +                reg = <4>;
>> +                function = LED_FUNCTION_STATUS;
>> +                color = <LED_COLOR_ID_RED>;
>> +            };
>> +
>> +            led@1f {
>> +                reg = <31>;
>> +                function = LED_FUNCTION_PANIC;
>> +                color = <LED_COLOR_ID_RED>;
>> +            };
>> +        };
>> +
>> +    };
>> -- 
>> 2.25.1
>>
>>