[PATCH v6 0/3] Add Turris Omnia LEDs driver

[PATCH v6 0/3] Add Turris Omnia LEDs driver

[Marek Behún]

Hi,

this is version 6 of LED driver for Turris Omnia, appliable on top
of Pavel's for-next branch.

Marek

changes since v5:
- added additionalProperties: false to yaml scheme as requested by Rob
- changed 'multi color' to 'multicolor' in commit message
- changed LEDS_CLASS_MULTI_COLOR to LEDS_CLASS_MULTICOLOR in Kconfig
  depend
- added Rob's reviewed-by tag to dt patch and Dan's to driver adding
  patch

changes since v4:
- fixed a typo in dt-binding
- change to dt-binding documentation as suggested by Dan Murphy so that
  it is less confusing
- cleaning up some things in the code addressed by Dan Murphy
- added sysfs ABI documentation for the brightness file controlling the
  brightness of the whole panel

changes since v3:
- added a note in yaml scheme to the description of multi-led property
  that no subnodes for the specific channels are needed since this
  controller only supports RGB LEDs. A comment into the device-tree
  example in the yaml scheme is added saying the same thing.

changes since v2:
- using multicolor LED framework now, major rewrite
- added support for global brightness (Omnia has a button which can
  switch between 8 levels of intensity of all the LEDs at once, but
  in reality any value between 0% and 100% can be set, and we want to
  access this setting via software)

Marek Behún (3):
  dt-bindings: leds: add cznic,turris-omnia-leds binding
  leds: initial support for Turris Omnia LEDs
  Documentation: ABI: leds-turris-omnia: document sysfs attribute

 .../sysfs-class-led-driver-turris-omnia       |  14 +
 .../leds/cznic,turris-omnia-leds.yaml         |  90 ++++++
 drivers/leds/Kconfig                          |  11 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-turris-omnia.c              | 293 ++++++++++++++++++
 5 files changed, 409 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-turris-omnia
 create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
 create mode 100644 drivers/leds/leds-turris-omnia.c

-- 
2.26.2

[PATCH v6 1/3] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Marek Behún]

Add device-tree bindings documentation for Turris Omnia RGB LEDs.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
---
 .../leds/cznic,turris-omnia-leds.yaml         | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml

diff --git a/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
new file mode 100644
index 000000000000..24ad1446445e
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/cznic,turris-omnia-leds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CZ.NIC's Turris Omnia LEDs driver
+
+maintainers:
+  - Marek Behún <marek.behun@nic.cz>
+
+description:
+  This module adds support for the RGB LEDs found on the front panel of the
+  Turris Omnia router. There are 12 RGB LEDs that are controlled by a
+  microcontroller that communicates via the I2C bus. Each LED is described
+  as a subnode of this I2C device.
+
+properties:
+  compatible:
+    const: cznic,turris-omnia-leds
+
+  reg:
+    description: I2C slave address of the microcontroller.
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^multi-led[0-9a-f]$":
+    type: object
+    allOf:
+      - $ref: leds-class-multicolor.yaml#
+    description:
+      This node represents one of the RGB LED devices on Turris Omnia.
+      No subnodes need to be added for subchannels since this controller only
+      supports RGB LEDs.
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 11
+        description:
+          This property identifies one of the LEDs on the front panel of the
+          Turris Omnia router.
+
+    required:
+      - reg
+
+additionalProperties: false
+
+examples:
+  - |
+
+    #include <dt-bindings/leds/common.h>
+
+    i2c0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@2b {
+            compatible = "cznic,turris-omnia-leds";
+            reg = <0x2b>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            multi-led@0 {
+                /*
+                 * No subnodes are needed, this controller only supports RGB
+                 * LEDs.
+                 */
+                reg = <0>;
+                color = <LED_COLOR_ID_MULTI>;
+                function = LED_FUNCTION_POWER;
+                linux,default-trigger = "heartbeat";
+            };
+
+            multi-led@a {
+                reg = <0xa>;
+                color = <LED_COLOR_ID_MULTI>;
+                function = LED_FUNCTION_INDICATOR;
+                function-enumerator = <1>;
+            };
+        };
+    };
+
+...
-- 
2.26.2

[PATCH v6 2/3] leds: initial support for Turris Omnia LEDs

[Marek Behún]

This adds basic support for LEDs on the front side of CZ.NIC's Turris
Omnia router.

There are 12 RGB LEDs. The controller supports HW triggering mode for
the LEDs, but this driver does not support it yet, and sets all the LEDs
defined in device-tree into SW mode upon probe.

This driver uses the multicolor LED framework.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Dan Murphy <dmurphy@ti.com>
---
 drivers/leds/Kconfig             |  11 ++
 drivers/leds/Makefile            |   1 +
 drivers/leds/leds-turris-omnia.c | 293 +++++++++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/leds/leds-turris-omnia.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a2c72212ddfc..454023d70979 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -176,6 +176,17 @@ config LEDS_EL15203000
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-el15203000.
 
+config LEDS_TURRIS_OMNIA
+	tristate "LED support for CZ.NIC's Turris Omnia"
+	depends on LEDS_CLASS_MULTICOLOR
+	depends on I2C
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	depends on OF
+	help
+	  This option enables basic support for the LEDs found on the front
+	  side of CZ.NIC's Turris Omnia router. There are 12 RGB LEDs on the
+	  front panel.
+
 config LEDS_LM3530
 	tristate "LCD Backlight driver for LM3530"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d684bc76d2b2..c2c7d7ade0d0 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -87,6 +87,7 @@ 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_TPS6105X)		+= leds-tps6105x.o
+obj-$(CONFIG_LEDS_TURRIS_OMNIA)		+= leds-turris-omnia.o
 obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
 obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o
 obj-$(CONFIG_LEDS_WRAP)			+= leds-wrap.o
diff --git a/drivers/leds/leds-turris-omnia.c b/drivers/leds/leds-turris-omnia.c
new file mode 100644
index 000000000000..c735e837ef48
--- /dev/null
+++ b/drivers/leds/leds-turris-omnia.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia LEDs driver
+ *
+ * 2020 by Marek Behun <marek.behun@nic.cz>
+ */
+
+#include <linux/i2c.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include "leds.h"
+
+#define OMNIA_BOARD_LEDS		12
+#define OMNIA_LED_NUM_CHANNELS		3
+
+#define CMD_LED_MODE			3
+#define CMD_LED_MODE_LED(l)		((l) & 0x0f)
+#define CMD_LED_MODE_USER		0x10
+
+#define CMD_LED_STATE			4
+#define CMD_LED_STATE_LED(l)		((l) & 0x0f)
+#define CMD_LED_STATE_ON		0x10
+
+#define CMD_LED_COLOR			5
+#define CMD_LED_SET_BRIGHTNESS		7
+#define CMD_LED_GET_BRIGHTNESS		8
+
+#define OMNIA_CMD			0
+
+#define OMNIA_CMD_LED_COLOR_LED		1
+#define OMNIA_CMD_LED_COLOR_R		2
+#define OMNIA_CMD_LED_COLOR_G		3
+#define OMNIA_CMD_LED_COLOR_B		4
+#define OMNIA_CMD_LED_COLOR_LEN		5
+
+struct omnia_led {
+	struct led_classdev_mc mc_cdev;
+	struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
+	int reg;
+};
+
+#define to_omnia_led(l)			container_of(l, struct omnia_led, mc_cdev)
+
+struct omnia_leds {
+	struct i2c_client *client;
+	struct mutex lock;
+	struct omnia_led leds[];
+};
+
+static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
+					     enum led_brightness brightness)
+{
+	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
+	struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
+	struct omnia_led *led = to_omnia_led(mc_cdev);
+	u8 buf[OMNIA_CMD_LED_COLOR_LEN], state;
+	int ret;
+
+	mutex_lock(&leds->lock);
+
+	led_mc_calc_color_components(&led->mc_cdev, brightness);
+
+	buf[OMNIA_CMD] = CMD_LED_COLOR;
+	buf[OMNIA_CMD_LED_COLOR_LED] = led->reg;
+	buf[OMNIA_CMD_LED_COLOR_R] = mc_cdev->subled_info[0].brightness;
+	buf[OMNIA_CMD_LED_COLOR_G] = mc_cdev->subled_info[1].brightness;
+	buf[OMNIA_CMD_LED_COLOR_B] = mc_cdev->subled_info[2].brightness;
+
+	state = CMD_LED_STATE_LED(led->reg);
+	if (buf[OMNIA_CMD_LED_COLOR_R] || buf[OMNIA_CMD_LED_COLOR_G] || buf[OMNIA_CMD_LED_COLOR_B])
+		state |= CMD_LED_STATE_ON;
+
+	ret = i2c_smbus_write_byte_data(leds->client, CMD_LED_STATE, state);
+	if (ret >= 0 && (state & CMD_LED_STATE_ON))
+		ret = i2c_master_send(leds->client, buf, 5);
+
+	mutex_unlock(&leds->lock);
+
+	return ret;
+}
+
+static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
+			      struct device_node *np)
+{
+	struct led_init_data init_data = {};
+	struct device *dev = &client->dev;
+	struct led_classdev *cdev;
+	int ret, color;
+
+	ret = of_property_read_u32(np, "reg", &led->reg);
+	if (ret || led->reg >= OMNIA_BOARD_LEDS) {
+		dev_warn(dev,
+			 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
+			 np, OMNIA_BOARD_LEDS - 1);
+		return 0;
+	}
+
+	ret = of_property_read_u32(np, "color", &color);
+	if (ret || color != LED_COLOR_ID_MULTI) {
+		dev_warn(dev,
+			 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_MULTI\n",
+			 np);
+		return 0;
+	}
+
+	led->subled_info[0].color_index = LED_COLOR_ID_RED;
+	led->subled_info[0].channel = 0;
+	led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
+	led->subled_info[1].channel = 1;
+	led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
+	led->subled_info[2].channel = 2;
+
+	led->mc_cdev.subled_info = led->subled_info;
+	led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
+
+	init_data.fwnode = &np->fwnode;
+
+	cdev = &led->mc_cdev.led_cdev;
+	cdev->max_brightness = 255;
+	cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
+
+	of_property_read_string(np, "linux,default-trigger", &cdev->default_trigger);
+
+	/* put the LED into software mode */
+	ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
+					CMD_LED_MODE_LED(led->reg) |
+					CMD_LED_MODE_USER);
+	if (ret < 0) {
+		dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np, ret);
+		return ret;
+	}
+
+	/* disable the LED */
+	ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE, CMD_LED_STATE_LED(led->reg));
+	if (ret < 0) {
+		dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
+		return ret;
+	}
+
+	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev, &init_data);
+	if (ret < 0) {
+		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
+		return ret;
+	}
+
+	return 1;
+}
+
+/*
+ * On the front panel of the Turris Omnia router there is also a button which can be used to control
+ * the intensity of all the LEDs at once, so that if they are too bright, user can dim them.
+ * The microcontroller cycles between 8 levels of this global brightness (from 100% to 0%), but this
+ * setting can have any integer value between 0 and 100. It is therefore convenient to be able to
+ * change this setting from software.
+ * We expose this setting via a sysfs attribute file called "brightness". This file lives in the
+ * device directory of the LED controller, not an individual LED, so it should not confuse users.
+ */
+static ssize_t brightness_show(struct device *dev, struct device_attribute *a, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_leds *leds = i2c_get_clientdata(client);
+	int ret;
+
+	mutex_lock(&leds->lock);
+	ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
+	mutex_unlock(&leds->lock);
+
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t brightness_store(struct device *dev, struct device_attribute *a, const char *buf,
+				size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_leds *leds = i2c_get_clientdata(client);
+	unsigned int brightness;
+	int ret;
+
+	if (sscanf(buf, "%u", &brightness) != 1)
+		return -EINVAL;
+
+	if (brightness > 100)
+		return -EINVAL;
+
+	mutex_lock(&leds->lock);
+	ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS, (u8) brightness);
+	mutex_unlock(&leds->lock);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_RW(brightness);
+
+static struct attribute *omnia_led_controller_attrs[] = {
+	&dev_attr_brightness.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(omnia_led_controller);
+
+static int omnia_leds_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct device_node *np = dev->of_node, *child;
+	struct omnia_leds *leds;
+	struct omnia_led *led;
+	int ret, count;
+
+	count = of_get_available_child_count(np);
+	if (!count) {
+		dev_err(dev, "LEDs are not defined in device tree!\n");
+		return -ENODEV;
+	} else if (count > OMNIA_BOARD_LEDS) {
+		dev_err(dev, "Too many LEDs defined in device tree!\n");
+		return -EINVAL;
+	}
+
+	leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
+	if (!leds)
+		return -ENOMEM;
+
+	leds->client = client;
+	i2c_set_clientdata(client, leds);
+
+	mutex_init(&leds->lock);
+
+	led = &leds->leds[0];
+	for_each_available_child_of_node(np, child) {
+		ret = omnia_led_register(client, led, child);
+		if (ret < 0)
+			return ret;
+
+		led += ret;
+	}
+
+	if (devm_device_add_groups(dev, omnia_led_controller_groups))
+		dev_warn(dev, "Could not add attribute group!\n");
+
+	return 0;
+}
+
+static int omnia_leds_remove(struct i2c_client *client)
+{
+	u8 buf[OMNIA_CMD_LED_COLOR_LEN];
+
+	/* put all LEDs into default (HW triggered) mode */
+	i2c_smbus_write_byte_data(client, CMD_LED_MODE,
+				  CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
+
+	/* set all LEDs color to [255, 255, 255] */
+	buf[OMNIA_CMD] = CMD_LED_COLOR;
+	buf[OMNIA_CMD_LED_COLOR_LED] = OMNIA_BOARD_LEDS;
+	buf[OMNIA_CMD_LED_COLOR_R] = 255;
+	buf[OMNIA_CMD_LED_COLOR_G] = 255;
+	buf[OMNIA_CMD_LED_COLOR_B] = 255;
+
+	i2c_master_send(client, buf, 5);
+
+	return 0;
+}
+
+static const struct of_device_id of_omnia_leds_match[] = {
+	{ .compatible = "cznic,turris-omnia-leds", },
+	{},
+};
+
+static const struct i2c_device_id omnia_id[] = {
+	{ "omnia", 0 },
+	{ }
+};
+
+static struct i2c_driver omnia_leds_driver = {
+	.probe		= omnia_leds_probe,
+	.remove		= omnia_leds_remove,
+	.id_table	= omnia_id,
+	.driver		= {
+		.name	= "leds-turris-omnia",
+		.of_match_table = of_omnia_leds_match,
+	},
+};
+
+module_i2c_driver(omnia_leds_driver);
+
+MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
+MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
+MODULE_LICENSE("GPL v2");
-- 
2.26.2

[PATCH v6 3/3] Documentation: ABI: leds-turris-omnia: document sysfs attribute

[Marek Behún]

Document the global brightness attribute for the Turris Omnia LED
controller.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
 .../testing/sysfs-class-led-driver-turris-omnia    | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-turris-omnia

diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-turris-omnia b/Documentation/ABI/testing/sysfs-class-led-driver-turris-omnia
new file mode 100644
index 000000000000..795a5de12fc1
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-driver-turris-omnia
@@ -0,0 +1,14 @@
+What:		/sys/class/leds/<led>/device/brightness
+Date:		July 2020
+KernelVersion:	5.9
+Contact:	Marek Behún <marek.behun@nic.cz>
+Description:	(RW) On the front panel of the Turris Omnia router there is also
+		a button which can be used to control the intensity of all the
+		LEDs at once, so that if they are too bright, user can dim them.
+
+		The microcontroller cycles between 8 levels of this global
+		brightness (from 100% to 0%), but this setting can have any
+		integer value between 0 and 100. It is therefore convenient to be
+		able to change this setting from software.
+
+		Format: %i
-- 
2.26.2

Re: [PATCH v6 2/3] leds: initial support for Turris Omnia LEDs

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 925 bytes --]

Hi!

> +
> +/*
> + * On the front panel of the Turris Omnia router there is also a button which can be used to control
> + * the intensity of all the LEDs at once, so that if they are too bright, user can dim them.
> + * The microcontroller cycles between 8 levels of this global brightness (from 100% to 0%), but this
> + * setting can have any integer value between 0 and 100. It is therefore convenient to be able to
> + * change this setting from software.
> + * We expose this setting via a sysfs attribute file called "brightness". This file lives in the
> + * device directory of the LED controller, not an individual LED, so it should not confuse users.
> + */

Lets keep comments formatted to 80 columns. This overflew my screen
and is unreadable.
							Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
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Re: [PATCH v6 2/3] leds: initial support for Turris Omnia LEDs

[Marek Behun]

On Wed, 22 Jul 2020 09:15:42 +0200
Pavel Machek <pavel@ucw.cz> wrote:

> Hi!
> 
> > +
> > +/*
> > + * On the front panel of the Turris Omnia router there is also a button which can be used to control
> > + * the intensity of all the LEDs at once, so that if they are too bright, user can dim them.
> > + * The microcontroller cycles between 8 levels of this global brightness (from 100% to 0%), but this
> > + * setting can have any integer value between 0 and 100. It is therefore convenient to be able to
> > + * change this setting from software.
> > + * We expose this setting via a sysfs attribute file called "brightness". This file lives in the
> > + * device directory of the LED controller, not an individual LED, so it should not confuse users.
> > + */  
> 
> Lets keep comments formatted to 80 columns. This overflew my screen
> and is unreadable.
> 							Pavel

OK. But you are aware that default limit was increased to 100 columns,
right?

Marek