Subject: [PATCH v3 1/3] leds: netxbig: add device tree binding

From: [email-masked] (Jacek Anaszewski)
Date: Tue, 23 Jun 2015 14:11:54 +0200

Hi Simon,

On 06/18/2015 04:59 PM, Simon Guinot wrote:
> This patch adds device tree support for the netxbig LEDs.
>
> This also introduces a additionnal DT binding for the GPIO extension bus
> (netxbig-gpio-ext) used to configure the LEDs. Since this bus could also
> be used to control other devices, then it seems more suitable to have it
> in a separate DT binding.
>
> Signed-off-by: Simon Guinot <[email-masked]>
> ---
> Changes since v1:
> - Check timer mode value retrieved from DT.
> - In netxbig_leds_get_of_pdata, don't use unsigned long variables to get
>    timer delay values from DT with function of_property_read_u32_index.
>    Instead, use a temporary u32 variable. This allows to silence a static
>    checker warning.
> - Make timer property optional in the binding documentation. It is now
>    aligned with the driver code.
>
> Changes since v2:
> - Fix pointer usage with the temporary u32 variable while calling
>    of_property_read_u32_index.
>
>   .../devicetree/bindings/gpio/netxbig-gpio-ext.txt  |  22 ++
>   .../devicetree/bindings/leds/leds-netxbig.txt      |  92 ++++++++
>   drivers/leds/leds-netxbig.c                        | 250 +++++++++++++++++++--
>   include/dt-bindings/leds/leds-netxbig.h            |  18 ++
>   4 files changed, 361 insertions(+), 21 deletions(-)
>   create mode 100644 Documentation/devicetree/bindings/gpio/netxbig-gpio-ext.txt
>   create mode 100644 Documentation/devicetree/bindings/leds/leds-netxbig.txt
>   create mode 100644 include/dt-bindings/leds/leds-netxbig.h
>
> diff --git a/Documentation/devicetree/bindings/gpio/netxbig-gpio-ext.txt b/Documentation/devicetree/bindings/gpio/netxbig-gpio-ext.txt
> new file mode 100644
> index 000000000000..e4fb2fe11086
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/netxbig-gpio-ext.txt
> @@ -0,0 +1,22 @@
> +Binding for the GPIO extension bus found on some LaCie/Seagate boards
> +(Example: 2Big/5Big Network v2, 2Big NAS).
> +
> +Required properties:
> +- compatible: "lacie,netxbig-gpio-ext".
> +- addr-gpios: GPIOs representing the address register.
> +- data-gpios: GPIOs representing the data register.
> +- enable-gpio: GPIO used to enable the new configuration (address, data).

Please mention that enable-gpio latches the settings on raising edge.

> +
> +Example:
> +
> +netxbig_gpio_ext: netxbig-gpio-ext {
> +	compatible = "lacie,netxbig-gpio-ext";
> +
> +	addr-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH
> +		      &gpio1 16 GPIO_ACTIVE_HIGH
> +		      &gpio1 17 GPIO_ACTIVE_HIGH>;
> +	data-gpios = <&gpio1 12 GPIO_ACTIVE_HIGH
> +		      &gpio1 13 GPIO_ACTIVE_HIGH
> +		      &gpio1 14 GPIO_ACTIVE_HIGH>;

You should indicate which element is MSB/LSB.

> +	enable-gpio = <&gpio0 29 GPIO_ACTIVE_HIGH>;
> +};

This needs gpio maintainer ack. Adding Linus and Alexandre.

Please also cc devicetree at vger.kernel.org always when modifying
DT bindings.

> diff --git a/Documentation/devicetree/bindings/leds/leds-netxbig.txt b/Documentation/devicetree/bindings/leds/leds-netxbig.txt
> new file mode 100644
> index 000000000000..efadbecbfeb9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-netxbig.txt
> @@ -0,0 +1,92 @@
> +Binding for the CPLD LEDs (GPIO extension bus) found on some LaCie/Seagate
> +boards (Example: 2Big/5Big Network v2, 2Big NAS).
> +
> +Required properties:
> +- compatible: "lacie,netxbig-leds".
> +- gpio-ext: Phandle for the gpio-ext bus.
> +
> +Optional properties:
> +- timers: Timer array. Each timer entry is represented by three integers:
> +  Mode (gpio-ext bus), delay_on and delay_off.
> +
> +Each LED is represented as a sub-node of the netxbig-leds device.
> +
> +Required sub-node properties:
> +- mode-addr: Mode register address on gpio-ext bus.
> +- mode-val: Mode to value mapping. Each entry is represented by two integers:
> +  A mode and the corresponding value on the gpio-ext bus.
> +- bright-addr: Brightness register address on gpio-ext bus.
> +- bright-max: Maximum brightness value.

We have a property led-max-microamp for this. Since LED subsystem
brightness level is not suitable for describing hardware properties,
we've switched to using microamperes. There is pending patch [1] that
makes the things more precise.

> +
> +Optional sub-node properties:
> +- label: Name for this LED. If omitted, the label is taken from the node name.
> +- linux,default-trigger: Trigger assigned to the LED.
> +
> +Example:
> +
> +netxbig-leds {
> +	compatible = "lacie,netxbig-leds";
> +
> +	gpio-ext = &gpio_ext;
> +
> +	timers = <NETXBIG_LED_TIMER1 500 500
> +		  NETXBIG_LED_TIMER2 500 1000>;
> +
> +	blue-power {
> +		label = "netxbig:blue:power";
> +		mode-addr = <0>;
> +		mode-val = <NETXBIG_LED_OFF 0
> +			    NETXBIG_LED_ON 1
> +			    NETXBIG_LED_TIMER1 3
> +			    NETXBIG_LED_TIMER2 7>;
> +		bright-addr = <1>;
> +		bright-max = <7>;
> +	};
> +	red-power {
> +		label = "netxbig:red:power";
> +		mode-addr = <0>;
> +		mode-val = <NETXBIG_LED_OFF 0
> +			    NETXBIG_LED_ON 2
> +			    NETXBIG_LED_TIMER1 4>;
> +		bright-addr = <1>;
> +		bright-max = <7>;
> +	};
> +	blue-sata0 {
> +		label = "netxbig:blue:sata0";
> +		mode-addr = <3>;
> +		mode-val = <NETXBIG_LED_OFF 0
> +			    NETXBIG_LED_ON 7
> +			    NETXBIG_LED_SATA 1
> +			    NETXBIG_LED_TIMER1 3>;
> +		bright-addr = <2>;
> +		bright-max = <7>;
> +	};
> +	red-sata0 {
> +		label = "netxbig:red:sata0";
> +		mode-addr = <3>;
> +		mode-val = <NETXBIG_LED_OFF 0
> +			    NETXBIG_LED_ON 2
> +			    NETXBIG_LED_TIMER1 4>;
> +		bright-addr = <2>;
> +		bright-max = <7>;
> +	};
> +	blue-sata1 {
> +		label = "netxbig:blue:sata1";
> +		mode-addr = <4>;
> +		mode-val = <NETXBIG_LED_OFF 0
> +			    NETXBIG_LED_ON 7
> +			    NETXBIG_LED_SATA 1
> +			    NETXBIG_LED_TIMER1 3>;
> +		bright-addr = <2>;
> +		bright-max = <7>;
> +	};
> +	red-sata1 {
> +		label = "netxbig:red:sata1";
> +		mode-addr = <4>;
> +		mode-val = <NETXBIG_LED_OFF 0
> +			    NETXBIG_LED_ON 2
> +			    NETXBIG_LED_TIMER1 4>;
> +		bright-addr = <2>;
> +		bright-max = <7>;
> +	};
> +};
> diff --git a/drivers/leds/leds-netxbig.c b/drivers/leds/leds-netxbig.c
> index 25e419752a7b..3649dfebd1d3 100644
> --- a/drivers/leds/leds-netxbig.c
> +++ b/drivers/leds/leds-netxbig.c
> @@ -26,6 +26,7 @@
>   #include <linux/spinlock.h>
>   #include <linux/platform_device.h>
>   #include <linux/gpio.h>
> +#include <linux/of_gpio.h>
>   #include <linux/leds.h>
>   #include <linux/platform_data/leds-kirkwood-netxbig.h>
>
> @@ -140,6 +141,11 @@ struct netxbig_led_data {
>   	spinlock_t		lock;
>   };
>
> +struct netxbig_led_priv {
> +	struct netxbig_led_platform_data *pdata;
> +	struct netxbig_led_data leds_data[];
> +};
> +
>   static int netxbig_led_get_timer_mode(enum netxbig_led_mode *mode,
>   				      unsigned long delay_on,
>   				      unsigned long delay_off,
> @@ -304,12 +310,12 @@ static void delete_netxbig_led(struct netxbig_led_data *led_dat)
>   	led_classdev_unregister(&led_dat->cdev);
>   }
>
> -static int
> -create_netxbig_led(struct platform_device *pdev,
> -		   struct netxbig_led_data *led_dat,
> -		   const struct netxbig_led *template)
> +static int create_netxbig_led(struct platform_device *pdev, int led,
> +			      struct netxbig_led_priv *priv)
>   {
> -	struct netxbig_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
> +	struct netxbig_led_platform_data *pdata = priv->pdata;
> +	struct netxbig_led_data *led_dat = &priv->leds_data[led];
> +	const struct netxbig_led *template = &priv->pdata->leds[led];
>
>   	spin_lock_init(&led_dat->lock);
>   	led_dat->gpio_ext = pdata->gpio_ext;
> @@ -346,38 +352,241 @@ create_netxbig_led(struct platform_device *pdev,
>   	return led_classdev_register(&pdev->dev, &led_dat->cdev);
>   }
>
> +#ifdef CONFIG_OF_GPIO
> +static int gpio_ext_get_of_pdata(struct device *dev, struct device_node *np,
> +				 struct netxbig_gpio_ext *gpio_ext)
> +{
> +	int *addr, *data;
> +	int num_addr, num_data;
> +	int ret;
> +	int i;
> +
> +	ret = of_gpio_named_count(np, "addr-gpios");
> +	if (ret < 0)
> +		return ret;

Please add error messages when parsing fails somewhere. There is a bit
to parse in this driver and the messages would make debugging easier.

> +	num_addr = ret;
> +	addr = devm_kzalloc(dev, num_addr * sizeof(unsigned int), GFP_KERNEL);
> +	if (!addr)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_addr; i++) {
> +		ret = of_get_named_gpio(np, "addr-gpios", i);
> +		if (ret < 0)
> +			return ret;
> +		addr[i] = ret;
> +	}
> +	gpio_ext->addr = addr;
> +	gpio_ext->num_addr = num_addr;
> +
> +	ret = of_gpio_named_count(np, "data-gpios");
> +	if (ret < 0)
> +		return ret;
> +	num_data = ret;
> +	data = devm_kzalloc(dev, num_data * sizeof(unsigned int), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_data; i++) {
> +		ret = of_get_named_gpio(np, "data-gpios", i);
> +		if (ret < 0)
> +			return ret;
> +		data[i] = ret;
> +	}
> +	gpio_ext->data = data;
> +	gpio_ext->num_data = num_data;
> +
> +	ret = of_get_named_gpio(np, "enable-gpio", 0);
> +	if (ret < 0)
> +		return ret;
> +	gpio_ext->enable = ret;
> +
> +	return 0;
> +}
> +
> +static int netxbig_leds_get_of_pdata(struct device *dev,
> +				     struct netxbig_led_platform_data *pdata)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct device_node *gpio_ext_np;
> +	struct device_node *child;
> +	struct netxbig_gpio_ext *gpio_ext;
> +	struct netxbig_led_timer *timers;
> +	struct netxbig_led *leds, *led;
> +	int num_timers;
> +	int num_leds = 0;
> +	int ret;
> +	int i;
> +
> +	/* GPIO extension */
> +	gpio_ext_np = of_parse_phandle(np, "gpio-ext", 0);
> +	if (!gpio_ext_np)
> +		return -EINVAL;

Please add error message here.

> +	gpio_ext = devm_kzalloc(dev, sizeof(struct netxbig_gpio_ext),
> +				GFP_KERNEL);

Kernel code style would be: sizeof(*gpio_ext). The same is relevant
to all other occurrences of sizeof in this file.

> +	if (!gpio_ext)
> +		return -ENOMEM;
> +	ret = gpio_ext_get_of_pdata(dev, gpio_ext_np, gpio_ext);
> +	if (ret)
> +		return ret;
> +	of_node_put(gpio_ext_np);
> +	pdata->gpio_ext = gpio_ext;
> +
> +	/* Timers (optional) */
> +	ret = of_property_count_u32_elems(np, "timers");
> +	if (ret > 0) {
> +		if (ret % 3)
> +			return -EINVAL;
> +		num_timers = ret / 3;
> +		timers = devm_kzalloc(dev,
> +				num_timers * sizeof(struct netxbig_led_timer),
> +				GFP_KERNEL);
> +		if (!timers)
> +			return -ENOMEM;
> +		for (i = 0; i < num_timers; i++) {
> +			u32 tmp;
> +
> +			of_property_read_u32_index(np, "timers", 3 * i,
> +						   &timers[i].mode);
> +			if (timers[i].mode >= NETXBIG_LED_MODE_NUM)
> +				return -EINVAL;
> +			of_property_read_u32_index(np, "timers",
> +						   3 * i + 1, &tmp);
> +			timers[i].delay_on = tmp;
> +			of_property_read_u32_index(np, "timers",
> +						   3 * i + 2, &tmp);
> +			timers[i].delay_off = tmp;

You could get rid of tmp by reformatting above as follows:

of_property_read_u32_index(np, "timers", 3 * i + 1,
                            &timers[i].delay_on);
of_property_read_u32_index(np, "timers", 3 * i + 2,
                            &timers[i].delay_off);

> +		}
> +		pdata->timer = timers;
> +		pdata->num_timer = num_timers;
> +	}
> +
> +	/* LEDs */
> +	num_leds = of_get_child_count(np);
> +	if (!num_leds)
> +		return -ENODEV;
> +
> +	leds = devm_kzalloc(dev, num_leds * sizeof(struct netxbig_led),
> +			    GFP_KERNEL);
> +	if (!leds)
> +		return -ENOMEM;
> +
> +	led = leds;
> +	for_each_child_of_node(np, child) {
> +		const char *string;
> +		int *mode_val;
> +		int num_modes;
> +
> +		if (!of_property_read_string(child, "label", &string))
> +			led->name = string;
> +		else
> +			led->name = child->name;
> +
> +		if (!of_property_read_string(child,
> +					     "linux,default-trigger", &string))
> +			led->default_trigger = string;

Please put above calls to of_property_read_string after all the
below conditions that can end up with returning an error.

> +
> +		if (of_property_read_u32(child, "mode-addr",
> +					 &led->mode_addr))
> +			return -EINVAL;
> +
> +		if (of_property_read_u32(child, "bright-addr",
> +					 &led->bright_addr))
> +			return -EINVAL;
> +
> +		mode_val = devm_kzalloc(dev,
> +					NETXBIG_LED_MODE_NUM * sizeof(int),
> +					GFP_KERNEL);
> +		if (!mode_val)
> +			return -ENOMEM;
> +
> +		for (i = 0; i < NETXBIG_LED_MODE_NUM; i++)
> +			mode_val[i] = NETXBIG_LED_INVALID_MODE;
> +
> +		ret = of_property_count_u32_elems(child, "mode-val");
> +		if (ret < 0 || ret % 2)
> +			return -EINVAL;
> +		num_modes = ret / 2;
> +		if (num_modes > NETXBIG_LED_MODE_NUM)
> +			return -EINVAL;
> +
> +		for (i = 0; i < num_modes; i++) {
> +			int mode;
> +			int val;
> +
> +			of_property_read_u32_index(child,
> +						   "mode-val", 2 * i, &mode);
> +			of_property_read_u32_index(child,
> +						   "mode-val", 2 * i + 1, &val);
> +			if (mode >= NETXBIG_LED_MODE_NUM)
> +				return -EINVAL;
> +			mode_val[mode] = val;
> +		}
> +		led->mode_val = mode_val;
> +
> +		led++;
> +	}
> +
> +	pdata->leds = leds;
> +	pdata->num_leds = num_leds;
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id of_netxbig_leds_match[] = {
> +	{ .compatible = "lacie,netxbig-leds", },
> +	{},
> +};
> +#else
> +static int netxbig_leds_get_of_pdata(struct device *dev,
> +				     struct netxbig_led_platform_data *pdata)
> +{
> +	return -ENODEV;
> +}
> +#endif /* CONFIG_OF_GPIO */
> +
>   static int netxbig_led_probe(struct platform_device *pdev)
>   {
>   	struct netxbig_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
> -	struct netxbig_led_data *leds_data;
> +	struct netxbig_led_priv *priv;
>   	int i;
>   	int ret;
>
> -	if (!pdata)
> -		return -EINVAL;
> +	if (!pdata) {
> +		pdata = devm_kzalloc(&pdev->dev,
> +				     sizeof(struct netxbig_led_platform_data),
> +				     GFP_KERNEL);
> +		if (!pdata)
> +			return -ENOMEM;
> +		ret = netxbig_leds_get_of_pdata(&pdev->dev, pdata);
> +		if (ret)
> +			return ret;
> +	}

You're removing board file for the device later in this patch set, but
in the same time you seem to expect pdata from board file as the
first choice and resort to parsing DT only if pdata is not available.
This is inconsistent. I'd leave the board file intact for now, also
because there can be some users of it.

BTW how do you compile the driver? I've tried to use
multi_v5_defconfig and mvebu_v5_defconfig and I have build breaks
with both of them on the recent linux-next.

>
> -	leds_data = devm_kzalloc(&pdev->dev,
> -		sizeof(struct netxbig_led_data) * pdata->num_leds, GFP_KERNEL);
> -	if (!leds_data)
> +	priv = devm_kzalloc(&pdev->dev,
> +			    sizeof(struct netxbig_led_priv) +
> +			    pdata->num_leds * sizeof(struct netxbig_led_data),
> +			    GFP_KERNEL);
> +	if (!priv)
>   		return -ENOMEM;
> +	priv->pdata = pdata;
>
>   	ret = gpio_ext_init(pdata->gpio_ext);
>   	if (ret < 0)
>   		return ret;
>
>   	for (i = 0; i < pdata->num_leds; i++) {
> -		ret = create_netxbig_led(pdev, &leds_data[i], &pdata->leds[i]);
> +		ret = create_netxbig_led(pdev, i, priv);
>   		if (ret < 0)
>   			goto err_free_leds;
>   	}
> -
> -	platform_set_drvdata(pdev, leds_data);
> +	platform_set_drvdata(pdev, priv);
>
>   	return 0;
>
>   err_free_leds:
>   	for (i = i - 1; i >= 0; i--)
> -		delete_netxbig_led(&leds_data[i]);
> +		delete_netxbig_led(&priv->leds_data[i]);
>
>   	gpio_ext_free(pdata->gpio_ext);
>   	return ret;
> @@ -385,14 +594,12 @@ err_free_leds:
>
>   static int netxbig_led_remove(struct platform_device *pdev)
>   {
> -	struct netxbig_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
> -	struct netxbig_led_data *leds_data;
> +	struct netxbig_led_priv *priv = platform_get_drvdata(pdev);
> +	struct netxbig_led_platform_data *pdata = priv->pdata;
>   	int i;
>
> -	leds_data = platform_get_drvdata(pdev);
> -
>   	for (i = 0; i < pdata->num_leds; i++)
> -		delete_netxbig_led(&leds_data[i]);
> +		delete_netxbig_led(&priv->leds_data[i]);
>
>   	gpio_ext_free(pdata->gpio_ext);
>
> @@ -403,7 +610,8 @@ static struct platform_driver netxbig_led_driver = {
>   	.probe		= netxbig_led_probe,
>   	.remove		= netxbig_led_remove,
>   	.driver		= {
> -		.name	= "leds-netxbig",
> +		.name		= "leds-netxbig",
> +		.of_match_table	= of_match_ptr(of_netxbig_leds_match),
>   	},
>   };
>
> diff --git a/include/dt-bindings/leds/leds-netxbig.h b/include/dt-bindings/leds/leds-netxbig.h
> new file mode 100644
> index 000000000000..92658b0310b2
> --- /dev/null
> +++ b/include/dt-bindings/leds/leds-netxbig.h
> @@ -0,0 +1,18 @@
> +/*
> + * This header provides constants for netxbig LED bindings.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2.  This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#ifndef _DT_BINDINGS_LEDS_NETXBIG_H
> +#define _DT_BINDINGS_LEDS_NETXBIG_H
> +
> +#define NETXBIG_LED_OFF		0
> +#define NETXBIG_LED_ON		1
> +#define NETXBIG_LED_SATA	2
> +#define NETXBIG_LED_TIMER1	3
> +#define NETXBIG_LED_TIMER2	4
> +
> +#endif /* _DT_BINDINGS_LEDS_NETXBIG_H */
>

[1] https://patchwork.ozlabs.org/patch/459991/

-- 
Best Regards,
Jacek Anaszewski