diff options
author | Alexandre Courbot <acourbot@nvidia.com> | 2013-12-03 03:20:11 (GMT) |
---|---|---|
committer | Linus Walleij <linus.walleij@linaro.org> | 2013-12-09 13:05:51 (GMT) |
commit | ad824783fb23bbc8295cffb6214b3b82d25f7d4a (patch) | |
tree | 745d128c1d04dca7a6c7b10dd737f116f13ddcb1 /drivers/gpio/gpiolib.c | |
parent | bdc54ef45d7670aeb52ce73f8b7ad5f3e5563661 (diff) | |
download | linux-ad824783fb23bbc8295cffb6214b3b82d25f7d4a.tar.xz |
gpio: better lookup method for platform GPIOs
Change the format of the platform GPIO lookup tables to make them less
confusing and improve lookup efficiency.
The previous format was a single linked-list that required to compare
the device name and function ID of every single GPIO defined for each
lookup. Switch that to a list of per-device tables, so that the lookup
can be done in two steps, omitting the GPIOs that are not relevant for a
particular device.
The matching rules are now defined as follows:
- The device name must match *exactly*, and can be NULL for GPIOs not
assigned to a particular device,
- If the function ID in the lookup table is NULL, the con_id argument of
gpiod_get() will not be used for lookup. However, if it is defined, it
must match exactly.
- The index must always match.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio/gpiolib.c')
-rw-r--r-- | drivers/gpio/gpiolib.c | 108 |
1 files changed, 58 insertions, 50 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 44a2327..4eb262a 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2260,18 +2260,14 @@ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep); /** - * gpiod_add_table() - register GPIO device consumers - * @table: array of consumers to register - * @num: number of consumers in table + * gpiod_add_lookup_table() - register GPIO device consumers + * @table: table of consumers to register */ -void gpiod_add_table(struct gpiod_lookup *table, size_t size) +void gpiod_add_lookup_table(struct gpiod_lookup_table *table) { mutex_lock(&gpio_lookup_lock); - while (size--) { - list_add_tail(&table->list, &gpio_lookup_list); - table++; - } + list_add_tail(&table->list, &gpio_lookup_list); mutex_unlock(&gpio_lookup_lock); } @@ -2327,72 +2323,84 @@ static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id, return desc; } -static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, - unsigned int idx, - enum gpio_lookup_flags *flags) +static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev) { const char *dev_id = dev ? dev_name(dev) : NULL; - struct gpio_desc *desc = ERR_PTR(-ENODEV); - unsigned int match, best = 0; - struct gpiod_lookup *p; + struct gpiod_lookup_table *table; mutex_lock(&gpio_lookup_lock); - list_for_each_entry(p, &gpio_lookup_list, list) { - match = 0; + list_for_each_entry(table, &gpio_lookup_list, list) { + if (table->dev_id && dev_id) { + /* + * Valid strings on both ends, must be identical to have + * a match + */ + if (!strcmp(table->dev_id, dev_id)) + goto found; + } else { + /* + * One of the pointers is NULL, so both must be to have + * a match + */ + if (dev_id == table->dev_id) + goto found; + } + } + table = NULL; - if (p->dev_id) { - if (!dev_id || strcmp(p->dev_id, dev_id)) - continue; +found: + mutex_unlock(&gpio_lookup_lock); + return table; +} - match += 2; - } +static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, + unsigned int idx, + enum gpio_lookup_flags *flags) +{ + struct gpio_desc *desc = ERR_PTR(-ENODEV); + struct gpiod_lookup_table *table; + struct gpiod_lookup *p; - if (p->con_id) { - if (!con_id || strcmp(p->con_id, con_id)) - continue; + table = gpiod_find_lookup_table(dev); + if (!table) + return desc; - match += 1; - } + for (p = &table->table[0]; p->chip_label; p++) { + struct gpio_chip *chip; + /* idx must always match exactly */ if (p->idx != idx) continue; - if (match > best) { - struct gpio_chip *chip; - - chip = find_chip_by_name(p->chip_label); - - if (!chip) { - dev_warn(dev, "cannot find GPIO chip %s\n", - p->chip_label); - continue; - } + /* If the lookup entry has a con_id, require exact match */ + if (p->con_id && (!con_id || strcmp(p->con_id, con_id))) + continue; - if (chip->ngpio <= p->chip_hwnum) { - dev_warn(dev, "GPIO chip %s has %d GPIOs\n", - chip->label, chip->ngpio); - continue; - } + chip = find_chip_by_name(p->chip_label); - desc = gpio_to_desc(chip->base + p->chip_hwnum); - *flags = p->flags; + if (!chip) { + dev_warn(dev, "cannot find GPIO chip %s\n", + p->chip_label); + continue; + } - if (match != 3) - best = match; - else - break; + if (chip->ngpio <= p->chip_hwnum) { + dev_warn(dev, "GPIO chip %s has %d GPIOs\n", + chip->label, chip->ngpio); + continue; } - } - mutex_unlock(&gpio_lookup_lock); + desc = gpiochip_offset_to_desc(chip, p->chip_hwnum); + *flags = p->flags; + } return desc; } /** * gpio_get - obtain a GPIO for a given GPIO function - * @dev: GPIO consumer + * @dev: GPIO consumer, can be NULL for system-global GPIOs * @con_id: function within the GPIO consumer * * Return the GPIO descriptor corresponding to the function con_id of device |