[RFC v6 2/8] drivers/pwm/core: Add support to remove registered consumer lookup tables

Shobhit Kumar
2015-04-24T15:42:32Z

In case some drivers are unloading, they can remove lookup tables which
they would have registered during their load time to avoid redundant
entries if loaded again

v2: Ccing maintainers

CC: Samuel Ortiz <sameo@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
---
drivers/pwm/core.c | 17 +++++++++++++++++
include/linux/pwm.h | 5 +++++
2 files changed, 22 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ba34c7d..d2fe7c8d 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -586,6 +586,23 @@ void pwm_add_table(struct pwm_lookup *table, size_t num)
}

/**
+ * pwm_remove_table() - un-register PWM device consumers
+ * @table: array of consumers to un-register
+ * @num: number of consumers in table
+ */
+void pwm_remove_table(struct pwm_lookup *table, size_t num)
+{
+ mutex_lock(&pwm_lookup_lock);
+
+ while (num--) {
+ list_del(&table->list);
+ table++;
+ }
+
+ mutex_unlock(&pwm_lookup_lock);
+}
+
+/**
* pwm_get() - look up and request a PWM device
* @dev: device for PWM consumer
* @con_id: consumer name
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index e90628c..cfe2d8d 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -290,10 +290,15 @@ struct pwm_lookup {

#if IS_ENABLED(CONFIG_PWM)
void pwm_add_table(struct pwm_lookup *table, size_t num);
+void pwm_remove_table(struct pwm_lookup *table, size_t num);
#else
static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
{
}
+
+static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
+{
+}
#endif

#ifdef CONFIG_PWM_SYSFS