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Date: Fri, 26 Mar 2021 06:56:00 +0100
From: Alexander Dahl <post@...pocky.de>
To: Hermes Zhang <chenhui.zhang@...s.com>
Cc: pavel@....cz, dmurphy@...com, robh+dt@...nel.org,
linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, chenhuiz@...s.com, lkml@...s.com,
kernel@...s.com
Subject: Re: [PATCH v2 2/2] leds: leds-multi-gpio: Add multiple GPIOs LED
driver
Hello Hermes,
great to see your improved series. See below for my remarks.
On Fri, Mar 26, 2021 at 01:28:01PM +0800, Hermes Zhang wrote:
> From: Hermes Zhang <chenhuiz@...s.com>
>
> Introduce a new multiple GPIOs LED driver. This LED will made of
> multiple GPIOs (up to 8) and will map different brightness to different
> GPIOs states which defined in dts file.
>
> Signed-off-by: Hermes Zhang <chenhuiz@...s.com>
> ---
> drivers/leds/Kconfig | 3 +
> drivers/leds/Makefile | 3 +
> drivers/leds/simple/Kconfig | 23 ++++
> drivers/leds/simple/Makefile | 3 +
> drivers/leds/simple/leds-multi-gpio.c | 144 ++++++++++++++++++++++++++
> 5 files changed, 176 insertions(+)
> create mode 100644 drivers/leds/simple/Kconfig
> create mode 100644 drivers/leds/simple/Makefile
> create mode 100644 drivers/leds/simple/leds-multi-gpio.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index b6742b4231bf..f95217b2fcf1 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -937,4 +937,7 @@ source "drivers/leds/trigger/Kconfig"
> comment "LED Blink"
> source "drivers/leds/blink/Kconfig"
>
> +comment "LED Simple"
> +source "drivers/leds/simple/Kconfig"
> +
> endif # NEW_LEDS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 2a698df9da57..26917d93fa03 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -111,3 +111,6 @@ obj-$(CONFIG_LEDS_TRIGGERS) += trigger/
>
> # LED Blink
> obj-$(CONFIG_LEDS_BLINK) += blink/
> +
> +# LED Blink
> +obj-$(CONFIG_LEDS_SIMPLE) += simple/
That comment should read "LED Simple", right?
> diff --git a/drivers/leds/simple/Kconfig b/drivers/leds/simple/Kconfig
> new file mode 100644
> index 000000000000..7aef82701f86
> --- /dev/null
> +++ b/drivers/leds/simple/Kconfig
> @@ -0,0 +1,23 @@
> +menuconfig LEDS_SIMPLE
> + bool "Simple LED support"
> + depends on LEDS_CLASS
> + help
> + This option enables simple leds support for the leds class.
> + If unsure, say Y.
> +
> +if LEDS_SIMPLE
> +
> +config LEDS_MULTI_GPIO
> + tristate "LED Support for multiple GPIOs LED"
> + depends on LEDS_CLASS
> + depends on GPIOLIB
> + depends on OF
> + help
> + This option enables support for a multiple GPIOs LED. Such LED is made
> + of multiple GPIOs and could change the brightness by setting different
> + states of the GPIOs.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called leds-multi-gpio.
> +
> +endif # LEDS_SIMPLE
I'm wondering why this is part of this driver? I suppose there's no
such folder yet, although Pavel suggested. Would it make sense to put
that Kconfig menu entry and folder creation to a separate commit?
> diff --git a/drivers/leds/simple/Makefile b/drivers/leds/simple/Makefile
> new file mode 100644
> index 000000000000..2ba655fdc175
> --- /dev/null
> +++ b/drivers/leds/simple/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +obj-$(CONFIG_LEDS_MULTI_GPIO) += leds-multi-gpio.o
> diff --git a/drivers/leds/simple/leds-multi-gpio.c b/drivers/leds/simple/leds-multi-gpio.c
> new file mode 100644
> index 000000000000..14fdaa5a2aac
> --- /dev/null
> +++ b/drivers/leds/simple/leds-multi-gpio.c
> @@ -0,0 +1,144 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Axis Communications AB
> + */
> +
> +#include <linux/leds.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +
> +
> +#define MAX_GPIO_NUM 8
> +
> +struct multi_gpio_led_priv {
> + struct led_classdev cdev;
> +
> + struct gpio_descs *gpios;
> +
> + u16 nr_states;
> +
> + u8 states[0];
> +};
> +
> +
> +static void multi_gpio_led_set(struct led_classdev *led_cdev,
> + enum led_brightness value)
> +{
> + struct multi_gpio_led_priv *priv;
> + int idx;
> +
> + DECLARE_BITMAP(values, MAX_GPIO_NUM);
> +
> + priv = container_of(led_cdev, struct multi_gpio_led_priv, cdev);
> +
> + idx = value > led_cdev->max_brightness ? led_cdev->max_brightness : value;
> +
> + values[0] = priv->states[idx];
> +
> + gpiod_set_array_value(priv->gpios->ndescs, priv->gpios->desc,
> + priv->gpios->info, values);
> +}
> +
> +static int multi_gpio_led_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + struct multi_gpio_led_priv *priv = NULL;
> + int ret;
> + const char *state = NULL;
> + struct led_init_data init_data = {};
> + struct gpio_descs *gpios;
> + u16 nr_states;
> +
> + gpios = devm_gpiod_get_array(dev, "led", GPIOD_OUT_LOW);
> + if (IS_ERR(gpios))
> + return PTR_ERR(gpios);
> +
> + if (gpios->ndescs >= MAX_GPIO_NUM) {
> + dev_err(dev, "Too many GPIOs\n");
> + return -EINVAL;
> + }
> +
> + ret = of_property_count_u8_elems(node, "led-states");
> + if (ret < 0)
> + return ret;
> +
> + if (ret != 1 << gpios->ndescs) {
> + dev_err(dev, "led-states number should equal to 2^led-gpios\n");
> + return -EINVAL;
> + }
> +
> + nr_states = ret;
> +
> + priv = devm_kzalloc(dev, sizeof(struct multi_gpio_led_priv)
> + + sizeof(u8) * nr_states , GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + ret = of_property_read_u8_array(node, "led-states", priv->states, nr_states);
> + if (ret)
> + return ret;
> +
> + priv->gpios = gpios;
> + priv->nr_states = nr_states;
> +
> + priv->cdev.max_brightness = nr_states;
> + priv->cdev.default_trigger = of_get_property(node, "linux,default-trigger", NULL);
> + priv->cdev.brightness_set = multi_gpio_led_set;
> +
> + init_data.fwnode = of_fwnode_handle(node);
> +
> + ret = devm_led_classdev_register_ext(dev, &priv->cdev, &init_data);
> + if (ret < 0)
> + return ret;
> +
> + of_property_read_string(node, "default-state", &state);
> + if (!strcmp(state, "on"))
> + multi_gpio_led_set(&priv->cdev, priv->cdev.max_brightness);
> + else
> + multi_gpio_led_set(&priv->cdev, 0);
> +
> + platform_set_drvdata(pdev, priv);
> +
> + return 0;
> +}
> +
> +static void multi_gpio_led_shutdown(struct platform_device *pdev)
> +{
> + struct multi_gpio_led_priv *priv = platform_get_drvdata(pdev);
> +
> + multi_gpio_led_set(&priv->cdev, 0);
> +}
> +
> +static int multi_gpio_led_remove(struct platform_device *pdev)
> +{
> + multi_gpio_led_shutdown(pdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id of_multi_gpio_led_match[] = {
> + { .compatible = "multi-gpio-led", },
> + {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, of_multi_gpio_led_match);
> +
> +static struct platform_driver multi_gpio_led_driver = {
> + .probe = multi_gpio_led_probe,
> + .remove = multi_gpio_led_remove,
> + .shutdown = multi_gpio_led_shutdown,
> + .driver = {
> + .name = "multi-gpio-led",
> + .of_match_table = of_multi_gpio_led_match,
> + },
> +};
> +
> +module_platform_driver(multi_gpio_led_driver);
> +
> +MODULE_AUTHOR("Hermes Zhang <chenhui.zhang@...s.com>");
> +MODULE_DESCRIPTION("Multiple GPIOs LED driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:leds-multi-gpio");
I did not review thouroughly, but in my mail the indentation looks
wrong. Did checkpatch complain?
Greets
Alex
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