Re: [PATCH 14/23] gpio: mockup: use the generic 'gpio-line-names' property

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Fri, Sep 04, 2020 at 05:45:38PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> 
> GPIO line names are currently created by the driver from the chip label.
> We'll want to support custom formats for line names (for instance: to
> name all lines the same) for user-space tests so create them in the
> module init function and pass them to the driver using the standard
> 'gpio-line-names' property.
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> ---
>  drivers/gpio/gpio-mockup.c | 70 +++++++++++++++++++++-----------------
>  1 file changed, 38 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
> index ce83f1df1933..96976ba66598 100644
> --- a/drivers/gpio/gpio-mockup.c
> +++ b/drivers/gpio/gpio-mockup.c
> @@ -18,6 +18,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/property.h>
>  #include <linux/slab.h>
> +#include <linux/string_helpers.h>
>  #include <linux/uaccess.h>
>  
>  #include "gpiolib.h"
> @@ -378,29 +379,6 @@ static void gpio_mockup_debugfs_setup(struct device *dev,
>  	return;
>  }
>  
> -static int gpio_mockup_name_lines(struct device *dev,
> -				  struct gpio_mockup_chip *chip)
> -{
> -	struct gpio_chip *gc = &chip->gc;
> -	char **names;
> -	int i;
> -
> -	names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL);
> -	if (!names)
> -		return -ENOMEM;
> -
> -	for (i = 0; i < gc->ngpio; i++) {
> -		names[i] = devm_kasprintf(dev, GFP_KERNEL,
> -					  "%s-%d", gc->label, i);
> -		if (!names[i])
> -			return -ENOMEM;
> -	}
> -
> -	gc->names = (const char *const *)names;
> -
> -	return 0;
> -}
> -
>  static void gpio_mockup_dispose_mappings(void *data)
>  {
>  	struct gpio_mockup_chip *chip = data;
> @@ -468,12 +446,6 @@ static int gpio_mockup_probe(struct platform_device *pdev)
>  	for (i = 0; i < gc->ngpio; i++)
>  		chip->lines[i].dir = GPIO_LINE_DIRECTION_IN;
>  
> -	if (device_property_read_bool(dev, "named-gpio-lines")) {
> -		rv = gpio_mockup_name_lines(dev, chip);
> -		if (rv)
> -			return rv;
> -	}
> -
>  	chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL,
>  							  gc->ngpio);
>  	if (IS_ERR(chip->irq_sim_domain))
> @@ -524,6 +496,27 @@ static void gpio_mockup_unregister_devices(void)
>  	}
>  }
>  
> +static __init char **gpio_mockup_make_line_names(const char *label,
> +						 unsigned int num_lines)
> +{
> +	unsigned int i;
> +	char **names;
> +
> +	names = kcalloc(num_lines + 1, sizeof(char *), GFP_KERNEL);
> +	if (!names)
> +		return NULL;
> +
> +	for (i = 0; i < num_lines; i++) {
> +		names[i] = kasprintf(GFP_KERNEL, "%s-%u", label, i);
> +		if (!names[i]) {
> +			kfree_strarray(names, i);
> +			return NULL;
> +		}
> +	}
> +
> +	return names;
> +}
> +
>  static int __init gpio_mockup_init(void)
>  {
>  	struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
> @@ -531,6 +524,7 @@ static int __init gpio_mockup_init(void)
>  	struct gpio_mockup_device *mockup_dev;
>  	int i, prop, num_chips, err = 0, base;
>  	struct platform_device_info pdevinfo;
> +	char **line_names;
>  	u16 ngpio;
>  
>  	if ((gpio_mockup_num_ranges < 2) ||
> @@ -563,6 +557,7 @@ static int __init gpio_mockup_init(void)
>  		memset(properties, 0, sizeof(properties));
>  		memset(&pdevinfo, 0, sizeof(pdevinfo));
>  		prop = 0;
> +		line_names = NULL;
>  
>  		snprintf(chip_label, sizeof(chip_label),
>  			 "gpio-mockup-%c", i + 'A');
> @@ -578,9 +573,18 @@ static int __init gpio_mockup_init(void)
>  				 : gpio_mockup_range_ngpio(i) - base;
>  		properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);
>  
> -		if (gpio_mockup_named_lines)
> -			properties[prop++] = PROPERTY_ENTRY_BOOL(
> -						"named-gpio-lines");
> +		if (gpio_mockup_named_lines) {
> +			line_names = gpio_mockup_make_line_names(chip_label,
> +								 ngpio);
> +			if (!line_names) {
> +				err = -ENOMEM;
> +				goto err_out;
> +			}
> +
> +			properties[prop++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
> +						"gpio-line-names",
> +						line_names, ngpio);
> +		}

Indentation here looks quite deep. Maybe introduce a helper in between where
you assign properties?

>  		pdevinfo.name = "gpio-mockup";
>  		pdevinfo.id = i;
> @@ -588,11 +592,13 @@ static int __init gpio_mockup_init(void)
>  
>  		mockup_dev = kzalloc(sizeof(*mockup_dev), GFP_KERNEL);
>  		if (!mockup_dev) {
> +			kfree_strarray(line_names, ngpio);
>  			err = -ENOMEM;
>  			goto err_out;
>  		}
>  
>  		mockup_dev->pdev = platform_device_register_full(&pdevinfo);
> +		kfree_strarray(line_names, ngpio);
>  		if (IS_ERR(mockup_dev->pdev)) {
>  			pr_err("error registering device");
>  			kfree(mockup_dev);
> -- 
> 2.26.1
> 

-- 
With Best Regards,
Andy Shevchenko