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Commit f9c4a31f authored by Thierry Reding's avatar Thierry Reding Committed by Linus Walleij
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gpiolib: Use seq_file's iterator interface 

When dumping a collection of items via seq_file, it is recommended to
use the iterator interface. For the gpiolib debugfs interface this can
be done to dump each GPIO chip in turn.

Note that for gpiolib this is a little cumbersome because it does not
provide a list of registered GPIO chips and the only way to iterate is
over each GPIO individually. Once a chip is found, the number of GPIOs
it provides can be skipped as a small optimization.

This patch was requested by Arnd Bergmann here:

	http://article.gmane.org/gmane.linux.ports.tegra/3535



Signed-off-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent d9875690

drivers/gpio/gpiolib.c

+74 −28
Original line number Diff line number Diff line
@@ -1773,30 +1773,69 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) 
	}

}



static int gpiolib_show(struct seq_file *s, void *unused)

static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)

{

	struct gpio_chip *chip = NULL;

	unsigned		gpio;

	int			started = 0;

	unsigned int gpio;

	void *ret = NULL;

	loff_t index = 0;



	/* REVISIT this isn't locked against gpio_chip removal ... */



	for (gpio = 0; gpio_is_valid(gpio); gpio++) {

		struct device *dev;



		if (chip == gpio_desc[gpio].chip)

		if (gpio_desc[gpio].chip == chip)

			continue;



		chip = gpio_desc[gpio].chip;

		if (!chip)

			continue;



		seq_printf(s, "%sGPIOs %d-%d",

				started ? "\n" : "",

		if (index++ >= *pos) {

			ret = chip;

			break;

		}

	}



	s->private = "";



	return ret;

}



static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)

{

	struct gpio_chip *chip = v;

	unsigned int gpio;

	void *ret = NULL;



	/* skip GPIOs provided by the current chip */

	for (gpio = chip->base + chip->ngpio; gpio_is_valid(gpio); gpio++) {

		chip = gpio_desc[gpio].chip;

		if (chip) {

			ret = chip;

			break;

		}

	}



	s->private = "\n";

	++*pos;



	return ret;

}



static void gpiolib_seq_stop(struct seq_file *s, void *v)

{

}



static int gpiolib_seq_show(struct seq_file *s, void *v)

{

	struct gpio_chip *chip = v;

	struct device *dev;



	seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,

			chip->base, chip->base + chip->ngpio - 1);

	dev = chip->dev;

	if (dev)

			seq_printf(s, ", %s/%s",

				dev->bus ? dev->bus->name : "no-bus",

		seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",

			dev_name(dev));

	if (chip->label)

		seq_printf(s, ", %s", chip->label);
@@ -1804,25 +1843,32 @@ static int gpiolib_show(struct seq_file *s, void *unused) 
		seq_printf(s, ", can sleep");

	seq_printf(s, ":\n");



		started = 1;

	if (chip->dbg_show)

		chip->dbg_show(s, chip);

	else

		gpiolib_dbg_show(s, chip);

	}



	return 0;

}



static const struct seq_operations gpiolib_seq_ops = {

	.start = gpiolib_seq_start,

	.next = gpiolib_seq_next,

	.stop = gpiolib_seq_stop,

	.show = gpiolib_seq_show,

};



static int gpiolib_open(struct inode *inode, struct file *file)

{

	return single_open(file, gpiolib_show, NULL);

	return seq_open(file, &gpiolib_seq_ops);

}



static const struct file_operations gpiolib_operations = {

	.owner		= THIS_MODULE,

	.open		= gpiolib_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

	.release	= seq_release,

};



static int __init gpiolib_debugfs_init(void)