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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: Thierry 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: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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1 changed files with 74 additions and 28 deletions
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@ -1773,30 +1773,69 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
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}
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}
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static int gpiolib_show(struct seq_file *s, void *unused)
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static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
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{
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struct gpio_chip *chip = NULL;
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unsigned gpio;
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int started = 0;
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unsigned int gpio;
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void *ret = NULL;
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loff_t index = 0;
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/* REVISIT this isn't locked against gpio_chip removal ... */
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for (gpio = 0; gpio_is_valid(gpio); gpio++) {
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struct device *dev;
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if (chip == gpio_desc[gpio].chip)
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if (gpio_desc[gpio].chip == chip)
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continue;
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chip = gpio_desc[gpio].chip;
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if (!chip)
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continue;
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seq_printf(s, "%sGPIOs %d-%d",
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started ? "\n" : "",
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if (index++ >= *pos) {
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ret = chip;
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break;
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}
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}
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s->private = "";
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return ret;
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}
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static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
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{
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struct gpio_chip *chip = v;
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unsigned int gpio;
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void *ret = NULL;
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/* skip GPIOs provided by the current chip */
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for (gpio = chip->base + chip->ngpio; gpio_is_valid(gpio); gpio++) {
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chip = gpio_desc[gpio].chip;
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if (chip) {
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ret = chip;
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break;
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}
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}
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s->private = "\n";
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++*pos;
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return ret;
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}
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static void gpiolib_seq_stop(struct seq_file *s, void *v)
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{
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}
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static int gpiolib_seq_show(struct seq_file *s, void *v)
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{
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struct gpio_chip *chip = v;
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struct device *dev;
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seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
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chip->base, chip->base + chip->ngpio - 1);
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dev = chip->dev;
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if (dev)
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seq_printf(s, ", %s/%s",
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dev->bus ? dev->bus->name : "no-bus",
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seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
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dev_name(dev));
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if (chip->label)
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seq_printf(s, ", %s", chip->label);
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@ -1804,25 +1843,32 @@ static int gpiolib_show(struct seq_file *s, void *unused)
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seq_printf(s, ", can sleep");
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seq_printf(s, ":\n");
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started = 1;
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if (chip->dbg_show)
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chip->dbg_show(s, chip);
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else
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gpiolib_dbg_show(s, chip);
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}
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return 0;
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}
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static const struct seq_operations gpiolib_seq_ops = {
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.start = gpiolib_seq_start,
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.next = gpiolib_seq_next,
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.stop = gpiolib_seq_stop,
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.show = gpiolib_seq_show,
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};
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static int gpiolib_open(struct inode *inode, struct file *file)
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{
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return single_open(file, gpiolib_show, NULL);
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return seq_open(file, &gpiolib_seq_ops);
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}
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static const struct file_operations gpiolib_operations = {
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.owner = THIS_MODULE,
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.open = gpiolib_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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.release = seq_release,
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};
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static int __init gpiolib_debugfs_init(void)
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