Ything-RepoMirrors/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-01-24 23:16:46 +00:00
Code Issues Packages Projects Releases Wiki Activity

gpiolib: allow multiple lookup tables per consumer

Browse Source 
The GPIO machine lookup mechanism dates back to old ARM board files
where lookup tables would all be defined in a single place. Since then,
lookup tables have also been used to address various DT and ACPI quirks
like missing GPIOs and - as of recently - setting up shared GPIO proxy
devices.

The lookup itself stops when we find the first matching table for a
consumer and - if it doesn't contain the right entry - the lookup fails.

Since the tables can now be defined in multiple places and we can't know
how many there are, effectively limiting a consumer to only a single
lookup table is no longer viable.

Rework the code to always look through all tables matching the consumer.

Link: https://lore.kernel.org/r/20251222-gpio-shared-reset-gpio-proxy-v1-1-8d4bba7d8c14@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
This commit is contained in:
Bartosz Golaszewski
2025-12-22 11:01:26 +01:00
parent a05543d6b0
commit 9700b0fccf
1 changed files with 56 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

91
drivers/gpio/gpiolib.c
View File

@@ -4508,45 +4508,41 @@ void gpiod_remove_hogs(struct gpiod_hog *hogs)
}
EXPORT_SYMBOL_GPL(gpiod_remove_hogs);
static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
static bool gpiod_match_lookup_table(struct device *dev,
const struct gpiod_lookup_table *table)
{
const char *dev_id = dev ? dev_name(dev) : NULL;
struct gpiod_lookup_table *table;
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))
return table;
} else {
/*
* One of the pointers is NULL, so both must be to have
* a match
*/
if (dev_id == table->dev_id)
return table;
}
lockdep_assert_held(&gpio_lookup_lock);
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))
return true;
} else {
/*
* One of the pointers is NULL, so both must be to have
* a match
*/
if (dev_id == table->dev_id)
return true;
}
return NULL;
return false;
}
static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
unsigned int idx, unsigned long *flags)
static struct gpio_desc *gpio_desc_table_match(struct device *dev, const char *con_id,
unsigned int idx, unsigned long *flags,
struct gpiod_lookup_table *table)
{
struct gpio_desc *desc = ERR_PTR(-ENOENT);
struct gpiod_lookup_table *table;
struct gpio_desc *desc;
struct gpiod_lookup *p;
struct gpio_chip *gc;
guard(mutex)(&gpio_lookup_lock);
table = gpiod_find_lookup_table(dev);
if (!table)
return desc;
lockdep_assert_held(&gpio_lookup_lock);
for (p = &table->table[0]; p->key; p++) {
/* idx must always match exactly */
@@ -4600,6 +4596,29 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
return desc;
}
return NULL;
}
static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
unsigned int idx, unsigned long *flags)
{
struct gpio_desc *desc = ERR_PTR(-ENOENT);
struct gpiod_lookup_table *table;
guard(mutex)(&gpio_lookup_lock);
list_for_each_entry(table, &gpio_lookup_list, list) {
if (!gpiod_match_lookup_table(dev, table))
continue;
desc = gpio_desc_table_match(dev, con_id, idx, flags, table);
if (!desc)
continue;
/* On IS_ERR() or match. */
return desc;
}
return desc;
}
@@ -4610,14 +4629,16 @@ static int platform_gpio_count(struct device *dev, const char *con_id)
unsigned int count = 0;
scoped_guard(mutex, &gpio_lookup_lock) {
table = gpiod_find_lookup_table(dev);
if (!table)
return -ENOENT;
list_for_each_entry(table, &gpio_lookup_list, list) {
if (!gpiod_match_lookup_table(dev, table))
continue;
for (p = &table->table[0]; p->key; p++) {
if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
(!con_id && !p->con_id))
count++;
for (p = &table->table[0]; p->key; p++) {
if ((con_id && p->con_id &&
!strcmp(con_id, p->con_id)) ||
(!con_id && !p->con_id))
count++;
}
}
}