Re: [PATCH v2 11/13] leds: max77650: add LEDs support

Jacek Anaszewski
2019-01-30T19:59:59Z

Hi Bartosz,

Thank you for the update.

One more thing drew my attention, please refer below.

On 1/29/19 2:35 PM, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> This adds basic support for LEDs for the max77650 PMIC. The device has
> three current sinks for driving LEDs.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
> drivers/leds/Kconfig | 6 ++
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-max77650.c | 152 +++++++++++++++++++++++++++++++++++
> 3 files changed, 159 insertions(+)
> create mode 100644 drivers/leds/leds-max77650.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index a72f97fca57b..6e7a8f51eccc 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -608,6 +608,12 @@ config LEDS_TLC591XX
> This option enables support for Texas Instruments TLC59108
> and TLC59116 LED controllers.
>
> +config LEDS_MAX77650
> + tristate "LED support for Maxim MAX77650 PMIC"
> + depends on MFD_MAX77650
> + help
> + LEDs driver for MAX77650 family of PMICs from Maxim Integrated."
> +
> config LEDS_MAX77693
> tristate "LED support for MAX77693 Flash"
> depends on LEDS_CLASS_FLASH
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 4c1b0054f379..f48b2404dbb7 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_LEDS_MC13783) += leds-mc13783.o
> obj-$(CONFIG_LEDS_NS2) += leds-ns2.o
> obj-$(CONFIG_LEDS_NETXBIG) += leds-netxbig.o
> obj-$(CONFIG_LEDS_ASIC3) += leds-asic3.o
> +obj-$(CONFIG_LEDS_MAX77650) += leds-max77650.o
> obj-$(CONFIG_LEDS_MAX77693) += leds-max77693.o
> obj-$(CONFIG_LEDS_MAX8997) += leds-max8997.o
> obj-$(CONFIG_LEDS_LM355x) += leds-lm355x.o
> diff --git a/drivers/leds/leds-max77650.c b/drivers/leds/leds-max77650.c
> new file mode 100644
> index 000000000000..e3a3c0e79b7a
> --- /dev/null
> +++ b/drivers/leds/leds-max77650.c
> @@ -0,0 +1,152 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Copyright (C) 2018 BayLibre SAS
> +// Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> +//
> +// LED driver for MAXIM 77650/77651 charger/power-supply.
> +
> +#include <linux/i2c.h>
> +#include <linux/leds.h>
> +#include <linux/mfd/max77650.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define MAX77650_NUM_LEDS 3
> +
> +#define MAX77650_LED_A_BASE 0x40
> +#define MAX77650_LED_B_BASE 0x43
> +
> +#define MAX77650_LED_BR_MASK GENMASK(4, 0)
> +#define MAX77650_LED_EN_MASK GENMASK(7, 6)
> +
> +/* Enable EN_LED_MSTR. */
> +#define MAX77650_LED_TOP_DEFAULT BIT(0)
> +
> +#define MAX77650_LED_ENABLE GENMASK(7, 6)
> +#define MAX77650_LED_DISABLE 0x00
> +
> +#define MAX77650_LED_A_DEFAULT MAX77650_LED_DISABLE
> +/* 100% on duty */
> +#define MAX77650_LED_B_DEFAULT GENMASK(3, 0)
> +
> +struct max77650_led {
> + struct led_classdev cdev;
> + struct regmap *map;
> + unsigned int regA;
> + unsigned int regB;
> +};
> +
> +static struct max77650_led *max77650_to_led(struct led_classdev *cdev)
> +{
> + return container_of(cdev, struct max77650_led, cdev);
> +}
> +
> +static int max77650_led_brightness_set(struct led_classdev *cdev,
> + enum led_brightness brightness)
> +{
> + struct max77650_led *led = max77650_to_led(cdev);
> + int val, mask;
> +
> + mask = MAX77650_LED_BR_MASK | MAX77650_LED_EN_MASK;
> +
> + if (brightness == LED_OFF) {
> + val = MAX77650_LED_DISABLE;
> + } else {
> + val = MAX77650_LED_ENABLE;
> + /*
> + * We can set the brightness with 5-bit resolution.
> + *
> + * For brightness == 1, the bits we're writing will be 0, but
> + * since we keep LED_FS0 set to 12.8mA full-scale range, the
> + * LED will be lit slightly.
> + */
> + val |= brightness / 8;

We have max_brightness property and you seem not to use it.
With 5-bit brightness resolution it should be initialized
to 32 and then we will be able to avoid the division here.

> + }
> +
> + return regmap_update_bits(led->map, led->regA, mask, val);
> +}
> +
> +static int max77650_led_probe(struct platform_device *pdev)
> +{
> + struct device_node *of_node, *child;
> + struct max77650_led *leds, *led;
> + struct device *parent;
> + struct device *dev;
> + struct regmap *map;
> + const char *label;
> + int rv, num_leds;
> + u32 reg;
> +
> + dev = &pdev->dev;
> + parent = dev->parent;
> + of_node = dev->of_node;
> +
> + if (!of_node)
> + return -ENODEV;
> +
> + leds = devm_kcalloc(dev, sizeof(*leds), MAX77650_NUM_LEDS, GFP_KERNEL);
> + if (!leds)
> + return -ENOMEM;
> +
> + map = dev_get_regmap(dev->parent, NULL);
> + if (!map)
> + return -ENODEV;
> +
> + num_leds = of_get_child_count(of_node);
> + if (!num_leds || num_leds > MAX77650_NUM_LEDS)
> + return -ENODEV;
> +
> + for_each_child_of_node(of_node, child) {
> + rv = of_property_read_u32(child, "reg", &reg);
> + if (rv || reg >= MAX77650_NUM_LEDS)
> + return -EINVAL;
> +
> + led = &leds[reg];
> + led->map = map;
> + led->regA = MAX77650_LED_A_BASE + reg;
> + led->regB = MAX77650_LED_B_BASE + reg;
> + led->cdev.brightness_set_blocking = max77650_led_brightness_set;
> +
> + label = of_get_property(child, "label", NULL);
> + if (!label) {
> + led->cdev.name = "max77650::";
> + } else {
> + led->cdev.name = devm_kasprintf(dev, GFP_KERNEL,
> + "max77650:%s", label);
> + if (!led->cdev.name)
> + return -ENOMEM;
> + }
> +
> + of_property_read_string(child, "linux,default-trigger",
> + &led->cdev.default_trigger);
> +
> + rv = devm_of_led_classdev_register(dev, child, &led->cdev);
> + if (rv)
> + return rv;
> +
> + rv = regmap_write(map, led->regA, MAX77650_LED_A_DEFAULT);
> + if (rv)
> + return rv;
> +
> + rv = regmap_write(map, led->regB, MAX77650_LED_B_DEFAULT);
> + if (rv)
> + return rv;
> + }
> +
> + return regmap_write(map,
> + MAX77650_REG_CNFG_LED_TOP,
> + MAX77650_LED_TOP_DEFAULT);
> +}
> +
> +static struct platform_driver max77650_led_driver = {
> + .driver = {
> + .name = "max77650-led",
> + },
> + .probe = max77650_led_probe,
> +};
> +module_platform_driver(max77650_led_driver);
> +
> +MODULE_DESCRIPTION("MAXIM 77650/77651 LED driver");
> +MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
> +MODULE_LICENSE("GPL v2");
>

--
Best regards,
Jacek Anaszewski