Re: [PATCH 2/4] leds: axp20x: Support charger LED on AXP20x like PMICs

[Dan Murphy <dmurphy@ti.com>]

Ondrej

On 2/23/20 7:14 AM, Ondrej Jirman wrote:
> There is single LED that can be turned on and off by the user, or set to
> be controlled by the charger in 2 different modes.
>
> The driver initializes the LED to be controlled by the charger, but
> allows to switch it to user control, and change the mode of charging
> indication via a sysfs.
>
> The driver was developed on AXP813, but should work on other PMICs like
> that without changes.
>
> Signed-off-by: Ondrej Jirman <megous@megous.com>
> ---
>   drivers/leds/Kconfig       |   7 ++
>   drivers/leds/Makefile      |   1 +
>   drivers/leds/leds-axp20x.c | 240 +++++++++++++++++++++++++++++++++++++
>   drivers/mfd/axp20x.c       |   3 +
>   4 files changed, 251 insertions(+)
>   create mode 100644 drivers/leds/leds-axp20x.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index d82f1dea37111..80a3f31f6f4c3 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -846,6 +846,13 @@ config LEDS_TPS6105X
>   	  It is a single boost converter primarily for white LEDs and
>   	  audio amplifiers.
>   
> +config LEDS_AXP20X
> +	tristate "Charger LED support for AXP20X-like PMICs (AXP813, ...)"
> +	depends on LEDS_CLASS && MFD_AXP20X
> +	help
> +	  This option enables support for on-chip LED driver on
> +	  AXP20X-like PMICs.
> +
>   comment "LED Triggers"
>   source "drivers/leds/trigger/Kconfig"
>   
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index d7e1107753fb1..80ea1bc4744b0 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -86,6 +86,7 @@ obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
>   obj-$(CONFIG_LEDS_LM3697)		+= leds-lm3697.o
>   obj-$(CONFIG_LEDS_LM36274)		+= leds-lm36274.o
>   obj-$(CONFIG_LEDS_TPS6105X)		+= leds-tps6105x.o
> +obj-$(CONFIG_LEDS_AXP20X)		+= leds-axp20x.o
>   
>   # LED SPI Drivers
>   obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o
> diff --git a/drivers/leds/leds-axp20x.c b/drivers/leds/leds-axp20x.c
> new file mode 100644
> index 0000000000000..e6c9853b84d52
> --- /dev/null
> +++ b/drivers/leds/leds-axp20x.c
> @@ -0,0 +1,240 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * LED Driver for X-Powers AXP813 PMIC and similar.
> + *
> + * Copyright(c) 2020 Ondrej Jirman <megous@megous.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/leds.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/mfd/axp20x.h>
> +
> +#define AXP20X_CHGLED_CTRL_MASK		BIT(3)
> +#define AXP20X_CHGLED_CTRL_CHARGER	BIT(3)
> +#define AXP20X_CHGLED_CTRL_USER		0
> +
> +#define AXP20X_CHRG_CTRL2_MODE		BIT(4)
> +
> +#define AXP20X_CHGLED_USER_STATE_MASK		GENMASK(5, 4)
> +#define AXP20X_CHGLED_USER_STATE_OFF		(0 << 4)
> +#define AXP20X_CHGLED_USER_STATE_BLINK_SLOW	(1 << 4)
> +#define AXP20X_CHGLED_USER_STATE_BLINK_FAST	(2 << 4)
> +#define AXP20X_CHGLED_USER_STATE_ON		(3 << 4)
> +
> +struct axp20x_led {
> +	struct led_classdev cdev;
> +	struct regmap *regmap;
> +};
> +
> +static int axp20x_led_set(struct led_classdev *led_cdev,
> +			   enum led_brightness value)
> +{
> +	struct axp20x_led *led =
> +			container_of(led_cdev, struct axp20x_led, cdev);
> +	unsigned int val;
> +
> +	val = value == LED_OFF ? AXP20X_CHGLED_USER_STATE_OFF :
> +		AXP20X_CHGLED_USER_STATE_ON;
> +
> +	return regmap_update_bits(led->regmap, AXP20X_OFF_CTRL,
> +				  AXP20X_CHGLED_USER_STATE_MASK, val);
> +
> +}
> +
> +static ssize_t charger_control_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +	struct axp20x_led *led =
> +		container_of(led_cdev, struct axp20x_led, cdev);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(led->regmap, AXP20X_OFF_CTRL, &val);
> +	if (ret)
> +		return ret;
> +
> +	return scnprintf(buf, PAGE_SIZE, "%u\n",
> +			 val & AXP20X_CHGLED_CTRL_MASK ? 1 : 0);
> +}
> +
> +static ssize_t charger_control_store(struct device *dev,
> +				     struct device_attribute *attr,
> +				     const char *buf, size_t len)
> +{
> +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +	struct axp20x_led *led =
> +			container_of(led_cdev, struct axp20x_led, cdev);
> +	bool status;
> +	int ret;
> +
> +	ret = kstrtobool(buf, &status);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_update_bits(led->regmap, AXP20X_OFF_CTRL,
> +				 AXP20X_CHGLED_CTRL_MASK,
> +				 status ? AXP20X_CHGLED_CTRL_CHARGER :
> +				 AXP20X_CHGLED_CTRL_USER);
> +	if (ret)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static ssize_t charger_mode_show(struct device *dev,
> +				 struct device_attribute *attr, char *buf)
> +{
> +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +	struct axp20x_led *led =
> +		container_of(led_cdev, struct axp20x_led, cdev);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(led->regmap, AXP20X_CHRG_CTRL2, &val);
> +	if (ret)
> +		return ret;
> +
> +	return scnprintf(buf, PAGE_SIZE, "%u\n",
> +			 val & AXP20X_CHRG_CTRL2_MODE ? 1 : 0);
> +}
> +
> +static ssize_t charger_mode_store(struct device *dev,
> +				  struct device_attribute *attr,
> +				  const char *buf, size_t len)
> +{
> +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +	struct axp20x_led *led =
> +		container_of(led_cdev, struct axp20x_led, cdev);
> +	unsigned int mode;
> +	int ret;
> +
> +	ret = kstrtouint(buf, 0, &mode);
> +	if (ret)
> +		return ret;
> +
> +	if (mode > 1)
> +		return -ERANGE;
> +
> +	ret = regmap_update_bits(led->regmap, AXP20X_CHRG_CTRL2,
> +				 AXP20X_CHRG_CTRL2_MODE,
> +				 mode ? AXP20X_CHRG_CTRL2_MODE : 0);
> +	if (ret)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static DEVICE_ATTR_RW(charger_control);
> +static DEVICE_ATTR_RW(charger_mode);
> +
> +static struct attribute *axp20x_led_attrs[] = {
> +	&dev_attr_charger_control.attr,
> +	&dev_attr_charger_mode.attr,
> +	NULL,
> +};
> +
> +ATTRIBUTE_GROUPS(axp20x_led);
> +
> +static int axp20x_led_probe(struct platform_device *pdev)
> +{
> +	struct axp20x_dev *axp20x;
> +	struct axp20x_led *led;
> +	int ret;
> +
> +	if (!of_device_is_available(pdev->dev.of_node))
> +		return -ENODEV;
> +
> +	axp20x = dev_get_drvdata(pdev->dev.parent);
> +	if (!axp20x)
> +		return -EINVAL;
> +
> +	led = devm_kzalloc(&pdev->dev,
> +			   sizeof(struct axp20x_led),
> +			   GFP_KERNEL);
> +	if (!led)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, led);
> +
> +	led->regmap = axp20x->regmap;
> +
> +	led->cdev.name = "axp20x-chgarger-led";


This does not follow the LED device naming convention please refer to 
the leds-class.rst document

https://elixir.bootlin.com/linux/latest/source/Documentation/leds/leds-class.rst

Dan