Re: [PATCH v2 2/2] leds: initial support for Turris Omnia LEDs

[Dan Murphy <dmurphy@ti.com>]

Marek

On 4/23/20 1:51 AM, Marek Behún wrote:
> 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
> into SW mode upon probe.
>
> The user can either group all three channels of one RGB LED into one LED
> classdev, or expose each channel as an individual LED classdev. This is
> done by utilizing the 'led-sources' and 'color' DT properties.

I think this would be a good candidate for the multicolor framework.  It 
would make the registration, brightness caching and color mapping easier

We are waiting on maintainer feedback for this.

https://lore.kernel.org/patchwork/project/lkml/list/?series=441958

But until then comments below

>
> Signed-off-by: Marek Behún <marek.behun@nic.cz>
> ---
>   drivers/leds/Kconfig             |  11 ++
>   drivers/leds/Makefile            |   1 +
>   drivers/leds/leds-turris-omnia.c | 285 +++++++++++++++++++++++++++++++
>   3 files changed, 297 insertions(+)
>   create mode 100644 drivers/leds/leds-turris-omnia.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index c664d84e1667..7663a5cd9fb5 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -145,6 +145,17 @@ 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
> +	depends on I2C
REGMAP?
> +	depends on MACH_ARMADA_38X || COMPILE_TEST
Why is tied to a Marvel processor?
> +	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 45235d5fb218..fd61421f7d40 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -83,6 +83,7 @@ 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..aafb4be9b225
> --- /dev/null
> +++ b/drivers/leds/leds-turris-omnia.c
> @@ -0,0 +1,285 @@
> +// 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/leds.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <uapi/linux/uleds.h>
> +#include "leds.h"
> +
> +#define OMNIA_BOARD_LEDS		12
> +
> +#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 cdev;
> +	int reg, color;
> +};
> +
> +#define to_omnia_led(l)	container_of(l, struct omnia_led, cdev)
> +
> +struct omnia_leds {
> +	struct i2c_client *client;
> +	struct mutex lock;
> +	u8 cache[OMNIA_BOARD_LEDS][3];
> +	int nleds;
> +	struct omnia_led leds[0];
No need for the [0] in the flexible array
> +};
> +
> +static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
> +					     enum led_brightness brightness)
> +{
> +	static const u8 color2cmd[] = {
> +		[LED_COLOR_ID_RED] = OMNIA_CMD_LED_COLOR_R,
> +		[LED_COLOR_ID_GREEN] = OMNIA_CMD_LED_COLOR_G,
> +		[LED_COLOR_ID_BLUE] = OMNIA_CMD_LED_COLOR_B,
> +	};
> +	struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
> +	struct omnia_led *led = to_omnia_led(cdev);
> +	u8 buf[OMNIA_CMD_LED_COLOR_LEN], state;
> +	int ret;
> +
> +	mutex_lock(&leds->lock);
> +
> +	buf[OMNIA_CMD] = CMD_LED_COLOR;
> +	buf[OMNIA_CMD_LED_COLOR_LED] = led->reg;
> +
> +	if (led->color == LED_COLOR_ID_WHITE) {
> +		buf[OMNIA_CMD_LED_COLOR_R] = brightness;
> +		buf[OMNIA_CMD_LED_COLOR_G] = brightness;
> +		buf[OMNIA_CMD_LED_COLOR_B] = brightness;
> +	} else {
> +		buf[OMNIA_CMD_LED_COLOR_R] = leds->cache[led->reg][0];
> +		buf[OMNIA_CMD_LED_COLOR_G] = leds->cache[led->reg][1];
> +		buf[OMNIA_CMD_LED_COLOR_B] = leds->cache[led->reg][2];
> +		buf[color2cmd[led->color]] = 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);
No check on ret?
> +
> +	leds->cache[led->reg][0] = buf[OMNIA_CMD_LED_COLOR_R];
> +	leds->cache[led->reg][1] = buf[OMNIA_CMD_LED_COLOR_G];
> +	leds->cache[led->reg][2] = buf[OMNIA_CMD_LED_COLOR_B];
> +
> +	mutex_unlock(&leds->lock);
> +
> +	return ret;
> +}
> +
> +static int omnia_led_register(struct omnia_leds *leds,
> +			      struct fwnode_handle *node)
> +{
> +	struct i2c_client *client = leds->client;
> +	struct led_init_data init_data = {};
> +	struct device *dev = &client->dev;
> +	struct omnia_led *led;
> +	int ret, nsources, color;
> +	u32 led_sources[3];
> +
> +	led = &leds->leds[leds->nleds];
> +
> +	nsources = fwnode_property_count_u32(node, "led-sources");
> +	if (nsources != 1 && nsources != 3) {
> +		dev_warn(dev,
> +			 "Node %pfw: 'led-sources' must contain either 1 or 3 items!\n",
> +			 node);
> +		return 0;
> +	}
> +
> +	ret = fwnode_property_read_u32_array(node, "led-sources", led_sources,
> +					     nsources);
> +	if (ret) {
> +		dev_err(dev, "Node %pfw: 'led-sources' read failed: %i\n",
> +			node, ret);
> +		return ret;
> +	}
> +
> +	ret = fwnode_property_read_u32(node, "color", &led->color);
> +	if (ret) {
> +		dev_warn(dev, "Node %pfw: 'color' read failed!\n",
> +			 node);
> +		return 0;
> +	}
> +
> +	if (nsources == 3) {
> +		if ((led_sources[0] % 3) != 0 ||
> +		    led_sources[1] != led_sources[0] + 1 ||
> +		    led_sources[2] != led_sources[0] + 2 ||
> +		    led_sources[2] >= OMNIA_BOARD_LEDS * 3) {
> +			dev_warn(dev, "Node %pfw has invalid 'led-sources'!\n",
> +				 node);
> +			return 0;
> +		}
> +
> +		color = LED_COLOR_ID_WHITE;
> +	} else {
> +		const int led_source_to_color[3] = {
> +			LED_COLOR_ID_RED,
> +			LED_COLOR_ID_GREEN,
> +			LED_COLOR_ID_BLUE
> +		};
> +		color = led_source_to_color[led_sources[0] % 3];
> +
> +		if (led_sources[0] >= OMNIA_BOARD_LEDS * 3) {
> +			dev_warn(dev, "Node %pfw has invalid 'led-sources'!\n",
> +				 node);
> +			return 0;
> +		}
> +	}
> +
> +	if (led->color != color) {
> +		dev_warn(dev, "Node %pfw: 'color' should be %s!\n", node,
> +			 led_colors[color]);
> +		return 0;
> +	}
> +
> +	init_data.fwnode = node;
> +
> +	led->reg = led_sources[0] / 3;
> +	led->cdev.max_brightness = 255;
> +	led->cdev.brightness_set_blocking = omnia_led_brightness_set_blocking;
> +
> +	fwnode_property_read_string(node, "linux,default-trigger",
> +				    &led->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 %pfw to software mode: %i\n", node,
> +			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 %pfw brightness: %i\n", node, ret);
> +		return ret;
> +	}
> +
> +	ret = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
> +	if (ret < 0) {
> +		dev_err(dev, "Cannot register LED %pfw: %i\n", node, ret);
> +		return ret;
> +	}
> +
> +	++leds->nleds;
> +
> +	return 0;
> +}
> +
> +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;
> +	int ret, count;
> +
> +	count = of_get_available_child_count(np);
device_get_child_node_count(&client->dev);
> +	if (!count) {
> +		dev_err(dev, "LEDs are not defined in device tree!\n");
> +		return -ENODEV;
> +	} else if (count > 3 * OMNIA_BOARD_LEDS) {
> +		dev_err(dev, "Too many LEDs defined in device tree!\n");
> +		return -EINVAL;
> +	}
> +
> +	leds = devm_kzalloc(dev, sizeof(*leds) + count * sizeof(leds->leds[0]),
> +			    GFP_KERNEL);
You can use this macro for flexible arrays struct_size(led, leds, count),
> +	if (!leds)
> +		return -ENOMEM;
> +
> +	leds->client = client;
> +	i2c_set_clientdata(client, leds);
> +
> +	mutex_init(&leds->lock);
> +
> +	for_each_available_child_of_node(np, child) {
> +		ret = omnia_led_register(leds, &child->fwnode);
> +		if (ret < 0)
if (ret) I don't see ret returning > 0
> +			return ret;
> +	}
> +
> +	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");