Re: [PATCH v2] leds: max5970: Add support for max5970

[Patrick Rudolph]

On Thu, Aug 24, 2023 at 12:49 PM Naresh Solanki
<naresh.solanki@xxxxxxxxxxxxx> wrote:
>
> From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
>
> The MAX5970 is hot swap controller and has 4 indication LED.
>
> Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
> ---
> Changes in V2:
> - Add of_node_put before return.
> - Code cleanup
> - Refactor code & remove max5970_setup_led function.
> ---
>  drivers/leds/Kconfig        |  11 ++++
>  drivers/leds/Makefile       |   1 +
>  drivers/leds/leds-max5970.c | 110 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 122 insertions(+)
>  create mode 100644 drivers/leds/leds-max5970.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index b92208eccdea..03ef527cc545 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -637,6 +637,17 @@ config LEDS_ADP5520
>           To compile this driver as a module, choose M here: the module will
>           be called leds-adp5520.
>
> +config LEDS_MAX5970
> +       tristate "LED Support for Maxim 5970"
> +       depends on LEDS_CLASS
> +       depends on MFD_MAX5970
> +       help
> +         This option enables support for the Maxim MAX5970 & MAX5978 smart
> +         switch indication LEDs via the I2C bus.
> +
> +         To compile this driver as a module, choose M here: the module will
> +         be called leds-max5970.
> +
>  config LEDS_MC13783
>         tristate "LED Support for MC13XXX PMIC"
>         depends on LEDS_CLASS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index d7348e8bc019..6eaee0a753c6 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_LEDS_LP8501)             += leds-lp8501.o
>  obj-$(CONFIG_LEDS_LP8788)              += leds-lp8788.o
>  obj-$(CONFIG_LEDS_LP8860)              += leds-lp8860.o
>  obj-$(CONFIG_LEDS_LT3593)              += leds-lt3593.o
> +obj-$(CONFIG_LEDS_MAX5970)             += leds-max5970.o
>  obj-$(CONFIG_LEDS_MAX77650)            += leds-max77650.o
>  obj-$(CONFIG_LEDS_MAX8997)             += leds-max8997.o
>  obj-$(CONFIG_LEDS_MC13783)             += leds-mc13783.o
> diff --git a/drivers/leds/leds-max5970.c b/drivers/leds/leds-max5970.c
> new file mode 100644
> index 000000000000..79277d47e1bc
> --- /dev/null
> +++ b/drivers/leds/leds-max5970.c
> @@ -0,0 +1,110 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Device driver for leds in MAX5970 and MAX5978 IC
> + *
> + * Copyright (c) 2022 9elements GmbH
> + *
> + * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> + */
> +
> +#include <linux/leds.h>
> +#include <linux/mfd/max5970.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define ldev_to_maxled(c)       container_of(c, struct max5970_led, cdev)
> +
> +struct max5970_led {
> +       struct device *dev;
> +       struct regmap *regmap;
> +       struct led_classdev cdev;
> +       unsigned int index;
> +};
> +
> +static int max5970_led_set_brightness(struct led_classdev *cdev,
> +                                     enum led_brightness brightness)
> +{
> +       struct max5970_led *ddata = ldev_to_maxled(cdev);
> +       int ret, val;
> +
> +       /* Set/clear corresponding bit for given led index */
> +       val = !brightness ? BIT(ddata->index) : 0;
> +
> +       ret = regmap_update_bits(ddata->regmap, MAX5970_REG_LED_FLASH, BIT(ddata->index), val);
> +       if (ret < 0)
> +               dev_err(cdev->dev, "failed to set brightness %d", ret);
> +
> +       return ret;
> +}
> +
> +static int max5970_led_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct device_node *np = dev_of_node(dev->parent);
> +       struct regmap *regmap;
> +       struct device_node *led_node;
> +       struct device_node *child;
> +       struct max5970_led *ddata[MAX5970_NUM_LEDS];
> +       int ret = -ENODEV, num_leds = 0;
> +
> +       regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +       if (!regmap)
> +               return -EPROBE_DEFER;
> +
> +       led_node = of_get_child_by_name(np, "leds");
> +       if (!led_node)
> +               return -ENODEV;
> +
> +       for_each_available_child_of_node(led_node, child) {
> +               u32 reg;
> +
> +               if (of_property_read_u32(child, "reg", &reg))
> +                       continue;
> +
> +               if (reg >= MAX5970_NUM_LEDS) {
> +                       dev_err(dev, "invalid LED (%u >= %d)\n", reg, MAX5970_NUM_LEDS);
> +                       continue;
> +               }
> +
> +               ddata[num_leds] = devm_kzalloc(dev, sizeof(struct max5970_led), GFP_KERNEL);
> +               if (!ddata[num_leds]) {
> +                       of_node_put(child);
> +                       return -ENOMEM;
> +               }
This overflows if more than MAX5970_NUM_LEDS child nodes are present
in the node.
Better drop the array as you don't use it any more.

> +
> +               ddata[num_leds]->index = reg;
> +               ddata[num_leds]->regmap = regmap;
> +               ddata[num_leds]->dev = dev;
> +
> +               if (of_property_read_string(child, "label", &ddata[num_leds]->cdev.name))
> +                       ddata[num_leds]->cdev.name = child->name;
> +
> +               ddata[num_leds]->cdev.max_brightness = 1;
> +               ddata[num_leds]->cdev.brightness_set_blocking = max5970_led_set_brightness;
> +               ddata[num_leds]->cdev.default_trigger = "none";
> +
> +               ret = devm_led_classdev_register(ddata[num_leds]->dev, &ddata[num_leds]->cdev);
> +               if (ret < 0) {
> +                       of_node_put(child);
> +                       dev_err(dev, "Failed to initialize LED %u\n", reg);
> +                       return ret;
> +               }
> +               num_leds++;
> +       }
> +
> +       return ret;
> +}
> +
> +static struct platform_driver max5970_led_driver = {
> +       .driver = {
> +               .name = "max5970-led",
> +       },
> +       .probe = max5970_led_probe,
> +};
> +
> +module_platform_driver(max5970_led_driver);
> +MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>");
> +MODULE_AUTHOR("Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("MAX5970_hot-swap controller LED driver");
> +MODULE_LICENSE("GPL");
>
> base-commit: baca986e1f2c31f8e4b2a6d99d47c3bc844033e8
> --
> 2.41.0
>