Re: [PATCH 04/10] Input: ams_delta_serio: Replace power GPIO with regulator

[Dmitry Torokhov]

On Sat, Jun 09, 2018 at 04:02:18PM +0200, Janusz Krzysztofik wrote:
> Modify the driver so it no longer requests and manipulates the
> "keybrd_pwr" GPIO pin but a "vcc" regulator supply instead.
> 
> For this to work with Amstrad Delta, define a regulator over the
> "keybrd_pwr" GPIO pin with the "vcc" supply for ams-delta-serio device
> and register it from the board file.  Both assign an absulute GPIO
> number to the soon depreciated .gpio member of the regulator config
> structure, and also build and register a GPIO lookup table so it is
> ready for use by the regulator driver as soon as its upcoming update
> is applied.
> 
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@xxxxxxxxx>
> ---
>  arch/arm/mach-omap1/board-ams-delta.c | 63 +++++++++++++++++++++++++++++++++--
>  drivers/input/serio/ams_delta_serio.c | 27 ++++++++++-----
>  2 files changed, 79 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/arm/mach-omap1/board-ams-delta.c b/arch/arm/mach-omap1/board-ams-delta.c
> index 2119d2d3ba84..706eb2f9301d 100644
> --- a/arch/arm/mach-omap1/board-ams-delta.c
> +++ b/arch/arm/mach-omap1/board-ams-delta.c
> @@ -509,6 +509,46 @@ static struct platform_device ams_delta_serio_device = {
>  	.id		= PLATFORM_DEVID_NONE,
>  };
>  
> +static struct regulator_consumer_supply keybrd_pwr_consumers[] = {
> +	/*
> +	 * Initialize supply .dev_name with NULL.  It will be replaced
> +	 * with serio dev_name() as soon as the serio device is registered.
> +	 */
> +	REGULATOR_SUPPLY("vcc", NULL),
> +};
> +
> +static struct regulator_init_data keybrd_pwr_initdata = {
> +	.constraints		= {
> +		.valid_ops_mask		= REGULATOR_CHANGE_STATUS,
> +	},
> +	.num_consumer_supplies	= ARRAY_SIZE(keybrd_pwr_consumers),
> +	.consumer_supplies	= keybrd_pwr_consumers,
> +};
> +
> +static struct fixed_voltage_config keybrd_pwr_config = {
> +	.supply_name		= "keybrd_pwr",
> +	.microvolts		= 5000000,
> +	.gpio			= AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
> +	.enable_high		= 1,
> +	.init_data		= &keybrd_pwr_initdata,
> +};
> +
> +static struct platform_device keybrd_pwr_device = {
> +	.name	= "reg-fixed-voltage",
> +	.id	= PLATFORM_DEVID_AUTO,
> +	.dev	= {
> +		.platform_data	= &keybrd_pwr_config,
> +	},
> +};
> +
> +static struct gpiod_lookup_table keybrd_pwr_gpio_table = {
> +	.table = {
> +		GPIO_LOOKUP(LATCH2_LABEL, LATCH2_PIN_KEYBRD_PWR, NULL,
> +			    GPIO_ACTIVE_HIGH),
> +		{ },
> +	},
> +};
> +
>  static struct platform_device *ams_delta_devices[] __initdata = {
>  	&latch1_gpio_device,
>  	&latch2_gpio_device,
> @@ -526,6 +566,7 @@ static struct platform_device *late_devices[] __initdata = {
>  
>  static struct gpiod_lookup_table *ams_delta_gpio_tables[] __initdata = {
>  	&ams_delta_audio_gpio_table,
> +	&keybrd_pwr_gpio_table,
>  };
>  
>  static struct gpiod_lookup_table *late_gpio_tables[] __initdata = {
> @@ -566,12 +607,30 @@ static void __init ams_delta_init(void)
>  	platform_add_devices(ams_delta_devices, ARRAY_SIZE(ams_delta_devices));
>  
>  	/*
> -	 * As soon as devices have been registered, assign their dev_names
> -	 * to respective GPIO lookup tables before they are added.
> +	 * As soon as regulator consumers have been registered, assign their
> +	 * dev_names to consumer supply entries of respective regulators.
> +	 */
> +	keybrd_pwr_consumers[0].dev_name =
> +			dev_name(&ams_delta_serio_device.dev);
> +
> +	/*
> +	 * Once consumer supply entries are populated with dev_names,
> +	 * register regulator devices.  At this stage only the keyboard
> +	 * power regulator has its consumer supply table fully populated.
> +	 */
> +	platform_device_register(&keybrd_pwr_device);
> +
> +	/*
> +	 * As soon as GPIO consumers have been registered, assign
> +	 * their dev_names to respective GPIO lookup tables.
>  	 */
>  	ams_delta_audio_gpio_table.dev_id =
>  			dev_name(&ams_delta_audio_device.dev);
> +	keybrd_pwr_gpio_table.dev_id = dev_name(&keybrd_pwr_device.dev);
>  
> +	/*
> +	 * Once GPIO lookup tables are populated with dev_names, register them.
> +	 */
>  	gpiod_add_lookup_tables(ams_delta_gpio_tables,
>  				ARRAY_SIZE(ams_delta_gpio_tables));
>  
> diff --git a/drivers/input/serio/ams_delta_serio.c b/drivers/input/serio/ams_delta_serio.c
> index 551a4fa73fe4..d48beab1d00d 100644
> --- a/drivers/input/serio/ams_delta_serio.c
> +++ b/drivers/input/serio/ams_delta_serio.c
> @@ -23,6 +23,7 @@
>  #include <linux/gpio.h>
>  #include <linux/irq.h>
>  #include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/serio.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
> @@ -39,6 +40,7 @@ MODULE_LICENSE("GPL");
>  
>  struct ams_delta_serio {
>  	struct serio *serio;
> +	struct regulator *vcc;
>  };
>  
>  static int check_data(struct serio *serio, int data)
> @@ -94,16 +96,18 @@ static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
>  
>  static int ams_delta_serio_open(struct serio *serio)
>  {
> -	/* enable keyboard */
> -	gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 1);
> +	struct ams_delta_serio *priv = serio->port_data;
>  
> -	return 0;
> +	/* enable keyboard */
> +	return regulator_enable(priv->vcc);
>  }
>  
>  static void ams_delta_serio_close(struct serio *serio)
>  {
> +	struct ams_delta_serio *priv = serio->port_data;
> +
>  	/* disable keyboard */
> -	gpio_set_value(AMS_DELTA_GPIO_PIN_KEYBRD_PWR, 0);
> +	regulator_disable(priv->vcc);
>  }
>  
>  static const struct gpio ams_delta_gpios[] __initconst_or_module = {
> @@ -117,11 +121,6 @@ static const struct gpio ams_delta_gpios[] __initconst_or_module = {
>  		.flags	= GPIOF_DIR_IN,
>  		.label	= "serio-clock",
>  	},
> -	{
> -		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_PWR,
> -		.flags	= GPIOF_OUT_INIT_LOW,
> -		.label	= "serio-power",
> -	},
>  	{
>  		.gpio	= AMS_DELTA_GPIO_PIN_KEYBRD_DATAOUT,
>  		.flags	= GPIOF_OUT_INIT_LOW,
> @@ -146,6 +145,16 @@ static int ams_delta_serio_init(struct platform_device *pdev)
>  		goto serio;
>  	}
>  
> +	priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
> +	if (IS_ERR(priv->vcc)) {
> +		err = PTR_ERR(priv->vcc);
> +		dev_err(&pdev->dev, "regulator request failed (%d)\n", err);
> +		/* Fail softly if the regulator is not available yet */
> +		if (err == -ENODEV)
> +			err = -EPROBE_DEFER;

Hmm, if regulator is not ready yet, devm_regulator_get() should be
returning -EPROBE_DEFER already, we should not have to convert -ENODEV
to -EPROBE_DEFER...

Is it because we have_full_constraints() returns false? You might need
to add call to regulator_has_full_constraints() to your board file.

> +		goto gpio;
> +	}
> +
>  	err = request_irq(gpio_to_irq(AMS_DELTA_GPIO_PIN_KEYBRD_CLK),
>  			ams_delta_serio_interrupt, IRQ_TYPE_EDGE_RISING,
>  			DRIVER_NAME, priv);
> -- 
> 2.16.1
> 

Thanks.

-- 
Dmitry