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Subject: Re: [PATCH v2 2/3] leds: upboard: Add LED support
To:     Dan O'Donovan <dan@emutex.com>, linux-kernel@vger.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Lee Jones <lee.jones@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Pavel Machek <pavel@ucw.cz>, linux-gpio@vger.kernel.org,
        linux-leds@vger.kernel.org,
        Carlos Iglesias <carlos.iglesias@emutex.com>,
        Javier Arteaga <javier@emutex.com>
References: <20180421085009.28773-1-javier@emutex.com>
 <1539969334-24577-1-git-send-email-dan@emutex.com>
 <1539969334-24577-3-git-send-email-dan@emutex.com>
From:   Jacek Anaszewski <jacek.anaszewski@gmail.com>
Message-ID: <ede59ef8-7caf-413d-6858-33a1eab5f084@gmail.com>
Date:   Tue, 23 Oct 2018 20:50:48 +0200
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Hi Javier,

Thank you for the patch.

I have few trivial issues below, please take a look.

On 10/19/2018 07:15 PM, Dan O'Donovan wrote:
> From: Javier Arteaga <javier@emutex.com>
> 
> Allow userspace to use the on-board LEDs as "upboard:<color>:".
> 
> Acked-by: Pavel Machek <pavel@ucw.cz>
> Signed-off-by: Javier Arteaga <javier@emutex.com>
> Signed-off-by: Dan O'Donovan <dan@emutex.com>
> ---
>  drivers/leds/Kconfig        |  10 +++++
>  drivers/leds/Makefile       |   1 +
>  drivers/leds/leds-upboard.c | 104 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 115 insertions(+)
>  create mode 100644 drivers/leds/leds-upboard.c
> 
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 44097a3..0ed8857 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -756,6 +756,16 @@ config LEDS_NIC78BX
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called leds-nic78bx.
>  
> +config LEDS_UPBOARD
> +	tristate "LED support for the UP Squared"
> +	depends on LEDS_CLASS
> +	depends on MFD_UPBOARD
> +	help
> +	  This option enables support for the LEDs on the UP Squared board.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called leds-upboard.
> +
>  comment "LED Triggers"
>  source "drivers/leds/trigger/Kconfig"
>  
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 420b5d2..c85f18f 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -78,6 +78,7 @@ obj-$(CONFIG_LEDS_MT6323)		+= leds-mt6323.o
>  obj-$(CONFIG_LEDS_LM3692X)		+= leds-lm3692x.o
>  obj-$(CONFIG_LEDS_SC27XX_BLTC)		+= leds-sc27xx-bltc.o
>  obj-$(CONFIG_LEDS_LM3601X)		+= leds-lm3601x.o
> +obj-$(CONFIG_LEDS_UPBOARD)		+= leds-upboard.o
>  
>  # LED SPI Drivers
>  obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o
> diff --git a/drivers/leds/leds-upboard.c b/drivers/leds/leds-upboard.c
> new file mode 100644
> index 0000000..34a6973
> --- /dev/null
> +++ b/drivers/leds/leds-upboard.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// UP Board LED driver
> +//
> +// Copyright (c) 2018, Emutex Ltd.
> +//
> +// Author: Javier Arteaga <javier@emutex.com>
> +//
> +
> +#include <linux/kernel.h>
> +#include <linux/leds.h>
> +#include <linux/mfd/upboard.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/acpi.h>

The last include should go first to keep alphabetical order.

> +
> +#define to_upboard_led(cdev) container_of(cdev, struct upboard_led, cdev)
> +
> +static const char * const upboard_led_names[] = {
> +	"upboard:blue:",
> +	"upboard:yellow:",
> +	"upboard:green:",
> +	"upboard:red:",
> +};
> +
> +struct upboard_led {
> +	struct regmap_field *field;
> +	struct led_classdev cdev;
> +};
> +
> +static enum led_brightness upboard_led_brightness_get(struct led_classdev *cdev)
> +{
> +	struct upboard_led *led = to_upboard_led(cdev);
> +	int brightness = 0;
> +
> +	regmap_field_read(led->field, &brightness);

Please check the return value.

> +	return brightness;
> +}
> +
> +static void upboard_led_brightness_set(struct led_classdev *cdev,
> +				       enum led_brightness brightness)
> +{
> +	struct upboard_led *led = to_upboard_led(cdev);
> +
> +	regmap_field_write(led->field, brightness);

Ditto.

> +}
> +
> +static int upboard_led_probe(struct platform_device *pdev)
> +{
> +	unsigned int led_index = pdev->id;
> +	struct device *dev = &pdev->dev;
> +	struct acpi_device *adev;
> +	struct upboard_led *led;
> +	struct regmap *regmap;
> +	struct reg_field conf = {
> +		.reg = UPBOARD_REG_FUNC_EN0,
> +		.lsb = led_index,
> +		.msb = led_index,
> +	};
> +
> +	adev = ACPI_COMPANION(dev);
> +	if (!adev || strcmp(acpi_device_hid(adev), "AANT0F01"))
> +		return -ENODEV;
> +
> +	if (led_index >= ARRAY_SIZE(upboard_led_names))
> +		return -EINVAL;
> +
> +	if (!dev->parent)
> +		return -EINVAL;
> +
> +	regmap = dev_get_regmap(dev->parent, NULL);
> +	if (!regmap)
> +		return -EINVAL;
> +
> +	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
> +	if (!led)
> +		return -ENOMEM;
> +
> +	led->field = devm_regmap_field_alloc(dev, regmap, conf);
> +	if (IS_ERR(led->field))
> +		return PTR_ERR(led->field);
> +
> +	led->cdev.max_brightness = 1;

s/1/LED_ON/

> +	led->cdev.brightness_get = upboard_led_brightness_get;
> +	led->cdev.brightness_set = upboard_led_brightness_set;
> +	led->cdev.name = upboard_led_names[led_index];
> +
> +	return devm_led_classdev_register(dev, &led->cdev);
> +}
> +
> +static struct platform_driver upboard_led_driver = {
> +	.driver = {
> +		.name = "upboard-led",
> +	},
> +};
> +
> +module_platform_driver_probe(upboard_led_driver, upboard_led_probe);
> +
> +MODULE_ALIAS("platform:upboard-led");
> +MODULE_AUTHOR("Javier Arteaga <javier@emutex.com>");
> +MODULE_DESCRIPTION("UP Board LED driver");
> +MODULE_LICENSE("GPL v2");
> 

-- 
Best regards,
Jacek Anaszewski