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Date:	Tue, 30 Dec 2014 15:57:01 +0200
From:	Sakari Ailus <sakari.ailus@....fi>
To:	Pavel Machek <pavel@....cz>
Cc:	pali.rohar@...il.com, sre@...ian.org, sre@...g0.de,
	kernel list <linux-kernel@...r.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	linux-omap@...r.kernel.org, tony@...mide.com, khilman@...nel.org,
	aaro.koskinen@....fi, freemangordon@....bg, robh+dt@...nel.org,
	pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	bcousson@...libre.com, m.chehab@...sung.com,
	devicetree@...r.kernel.org, linux-media@...r.kernel.org,
	j.anaszewski@...sung.com
Subject: Re: [PATCHv2] media: i2c/adp1653: devicetree support for adp1653

Hi Pavel,

Thanks for the patch! A few comments below.

On Wed, Dec 24, 2014 at 11:34:34PM +0100, Pavel Machek wrote:
> 
> We are moving to device tree support on OMAP3, but that currently
> breaks ADP1653 driver. This adds device tree support, plus required
> documentation.
> 
> Signed-off-by: Pavel Machek <pavel@....cz>
> 
> ---
> 
> Changed -microsec to -us, as requested by devicetree people.
> 
> Fixed checkpatch issues.
> 
> diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
> index 2d88816..2c6c7c5 100644
> --- a/Documentation/devicetree/bindings/leds/common.txt
> +++ b/Documentation/devicetree/bindings/leds/common.txt
> @@ -14,6 +14,15 @@ Optional properties for child nodes:
>       "ide-disk" - LED indicates disk activity
>       "timer" - LED flashes at a fixed, configurable rate
>  
> +- max-microamp : maximum intensity in microamperes of the LED
> +	         (torch LED for flash devices)

s/torch LED/torch mode/

> +- flash-max-microamp : maximum intensity in microamperes of the
> +                       flash LED; it is mandatory if the LED should
> +		       support the flash mode
> +- flash-timeout-microsec : timeout in microseconds after which the flash
> +                           LED is turned off

These should go to a different patch.

> +
> +
>  Examples:
>  
>  system-status {
> @@ -21,3 +30,10 @@ system-status {
>  	linux,default-trigger = "heartbeat";
>  	...
>  };
> +
> +camera-flash {
> +	label = "Flash";
> +	max-microamp = <50000>;
> +	flash-max-microamp = <320000>;
> +	flash-timeout-microsec = <500000>;
> +}
> diff --git a/Documentation/devicetree/bindings/media/i2c/adp1653.txt b/Documentation/devicetree/bindings/media/i2c/adp1653.txt
> new file mode 100644
> index 0000000..3c7065f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/adp1653.txt
> @@ -0,0 +1,38 @@
> +* Analog Devices ADP1653 flash LED driver
> +
> +Required Properties:
> +
> +  - compatible: Must contain one of the following
> +    - "adi,adp1653"

I doubt whether there are going to be more chips supported with the driver.
There hasn't been since the driver was written not I'm aware of one now.

> +  - reg: I2C slave address
> +
> +  - gpios: References to the GPIO that controls the power for the chip.
> +
> +There are two led outputs available - flash and indicator. One led is
> +represented by one child node, nodes need to be named "flash" and "indicator".

80 characters per line.

> +
> +Required properties of the LED child node:
> +- max-microamp : see Documentation/devicetree/bindings/leds/common.txt
> +
> +Required properties of the flash LED child node:
> +
> +- flash-max-microamp : see Documentation/devicetree/bindings/leds/common.txt
> +- flash-timeout-us : see Documentation/devicetree/bindings/leds/common.txt
> +
> +Example:
> +
> +        adp1653: led-controller@30 {
> +                compatible = "adi,adp1653";
> +		reg = <0x30>;
> +                gpios = <&gpio3 24 GPIO_ACTIVE_HIGH>; /* 88 */

Please use tabs for indentation above (and below).

> +
> +		flash {
> +                        flash-timeout-us = <500000>;
> +                        flash-max-microamp = <320000>;
> +                        max-microamp = <50000>;
> +		};
> +                indicator {
> +                        max-microamp = <17500>;
> +		};
> +        };
> diff --git a/arch/arm/boot/dts/omap3-n900.dts b/arch/arm/boot/dts/omap3-n900.dts
> index bc82a12..d04e7cc 100644
> --- a/arch/arm/boot/dts/omap3-n900.dts
> +++ b/arch/arm/boot/dts/omap3-n900.dts
> @@ -553,6 +558,22 @@
>  
>  		ti,usb-charger-detection = <&isp1704>;
>  	};
> +
> +	adp1653: led-controller@30 {
> +		compatible = "adi,adp1653";
> +		reg = <0x30>;
> +		gpios = <&gpio3 24 GPIO_ACTIVE_HIGH>; /* 88 */
> +
> +		flash {
> +			flash-timeout-us = <500000>;
> +			flash-max-microamp = <320000>;
> +			max-microamp = <50000>;
> +		};
> +
> +		indicator {
> +			max-microamp = <17500>;
> +		};
> +	};

This should go to a separate patch as well.

>  };
>  
>  &i2c3 {
> diff --git a/drivers/media/i2c/adp1653.c b/drivers/media/i2c/adp1653.c
> index 873fe19..78341d0 100644
> --- a/drivers/media/i2c/adp1653.c
> +++ b/drivers/media/i2c/adp1653.c
> @@ -8,6 +8,7 @@
>   * Contributors:
>   *	Sakari Ailus <sakari.ailus@....fi>
>   *	Tuukka Toivonen <tuukkat76@...il.com>
> + *      Pavel Machek <pavel@....cz>
>   *
>   * This program is free software; you can redistribute it and/or
>   * modify it under the terms of the GNU General Public License
> @@ -34,9 +35,12 @@
>  #include <linux/module.h>
>  #include <linux/i2c.h>
>  #include <linux/slab.h>
> +#include <linux/of_gpio.h>
>  #include <media/adp1653.h>
>  #include <media/v4l2-device.h>
>  
> +#include <linux/gpio.h>

Please arrange along with the rest of headers.

> +
>  #define TIMEOUT_MAX		820000
>  #define TIMEOUT_STEP		54600
>  #define TIMEOUT_MIN		(TIMEOUT_MAX - ADP1653_REG_CONFIG_TMR_SET_MAX \
> @@ -306,9 +318,18 @@ adp1653_init_device(struct adp1653_flash *flash)
>  static int
>  __adp1653_set_power(struct adp1653_flash *flash, int on)
>  {
> -	int ret;
> +	int ret = 0;
> +
> +	if (flash->platform_data->power)
> +		ret = flash->platform_data->power(&flash->subdev, on);

if () {
} else {
}

> +	else {
> +		gpio_set_value(flash->platform_data->power_gpio, on);

Shouldn't you add this to the platform data struct?

power_gpio is actually a poor name for this, as is the "power" callback.
This is really "EN" gpio in the spec, I'd call it perhaps just "gpio", or
"enable_gpio".

> +		if (on) {
> +			/* Some delay is apparently required. */
> +			udelay(20);

The driver should always handle the delay, platform data or not. This
reminds me --- is there a need to retain the support for platform data? I
don't think it's being used anywhere. I'm fine with both keeping and
removing it.

> +		}
> +	}
>  
> -	ret = flash->platform_data->power(&flash->subdev, on);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -316,8 +337,13 @@ __adp1653_set_power(struct adp1653_flash *flash, int on)
>  		return 0;
>  
>  	ret = adp1653_init_device(flash);
> -	if (ret < 0)
> +	if (ret >= 0)
> +		return ret;
> +
> +	if (flash->platform_data->power)
>  		flash->platform_data->power(&flash->subdev, 0);
> +	else
> +		gpio_set_value(flash->platform_data->power_gpio, 0);
>  
>  	return ret;
>  }
> @@ -407,21 +433,78 @@ static int adp1653_resume(struct device *dev)
>  
>  #endif /* CONFIG_PM */
>  
> +static int adp1653_of_init(struct i2c_client *client,
> +			   struct adp1653_flash *flash,
> +			   struct device_node *node)
> +{
> +	u32 val;
> +	struct adp1653_platform_data *pd;
> +	enum of_gpio_flags flags;
> +	int gpio;
> +	struct device_node *child;
> +
> +	if (!node)
> +		return -EINVAL;
> +
> +	pd = devm_kzalloc(&client->dev, sizeof(*pd), GFP_KERNEL);
> +	if (!pd)
> +		return -ENOMEM;
> +	flash->platform_data = pd;
> +
> +	child = of_get_child_by_name(node, "flash");
> +	if (!child)
> +		return -EINVAL;
> +	if (of_property_read_u32(child, "flash-timeout-microsec", &val))
> +		return -EINVAL;
> +
> +	pd->max_flash_timeout = val;
> +	if (of_property_read_u32(child, "flash-max-microamp", &val))
> +		return -EINVAL;
> +	pd->max_flash_intensity = val/1000;
> +
> +	if (of_property_read_u32(child, "max-microamp", &val))
> +		return -EINVAL;
> +	pd->max_torch_intensity = val/1000;
> +
> +	child = of_get_child_by_name(node, "indicator");
> +	if (!child)
> +		return -EINVAL;

Do you require an indicator to be connected? I think it shouldn't be
mandatory, at least the driver should work without it, even if it exposes
the control (making that conditional would be a subject for another patch,
but that doesn't need to be done now).

> +	if (of_property_read_u32(child, "max-microamp", &val))
> +		return -EINVAL;
> +	pd->max_indicator_intensity = val;
> +
> +	if (!of_find_property(node, "gpios", NULL)) {
> +		dev_err(&client->dev, "No gpio node\n");
> +		return -EINVAL;
> +	}
> +
> +	gpio = of_get_gpio_flags(node, 0, &flags);

You could assign to pd->... here.

> +	if (gpio < 0) {
> +		dev_err(&client->dev, "Error getting GPIO\n");
> +		return -EINVAL;
> +	}
> +
> +	pd->power_gpio = gpio;
> +	return 0;
> +}
> +
> +
>  static int adp1653_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *devid)
>  {
>  	struct adp1653_flash *flash;
>  	int ret;
>  
> -	/* we couldn't work without platform data */
> -	if (client->dev.platform_data == NULL)
> -		return -ENODEV;
> -
>  	flash = devm_kzalloc(&client->dev, sizeof(*flash), GFP_KERNEL);
>  	if (flash == NULL)
>  		return -ENOMEM;
>  
>  	flash->platform_data = client->dev.platform_data;
> +	if (!flash->platform_data) {
> +		ret = adp1653_of_init(client, flash, client->dev.of_node);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	mutex_init(&flash->power_lock);
>  
> @@ -438,10 +521,11 @@ static int adp1653_probe(struct i2c_client *client,
>  		goto free_and_quit;
>  
>  	flash->subdev.entity.type = MEDIA_ENT_T_V4L2_SUBDEV_FLASH;
> -
> +

Huh? :-)

>  	return 0;
>  
>  free_and_quit:
> +	dev_err(&client->dev, "adp1653: failed to register device\n");
>  	v4l2_ctrl_handler_free(&flash->ctrls);
>  	return ret;
>  }
> @@ -464,7 +551,7 @@ static const struct i2c_device_id adp1653_id_table[] = {
>  };
>  MODULE_DEVICE_TABLE(i2c, adp1653_id_table);
>  
> -static struct dev_pm_ops adp1653_pm_ops = {
> +static const struct dev_pm_ops adp1653_pm_ops = {
>  	.suspend	= adp1653_suspend,
>  	.resume		= adp1653_resume,
>  };
> 
> 

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@....fi	XMPP: sailus@...iisi.org.uk
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