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MFD: ucb1x00-core: use mutexes instead of semaphores 

Convert the ucb1x00 driver to use mutexes rather than the depreciated
semaphores for exclusive access to the ADC.

Acked-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2012-01-21 09:33:38 +00:00
parent ddb1e04a35
commit cae154767a
2 changed files with 9 additions and 10 deletions
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15
drivers/mfd/ucb1x00-core.c
View File

@ -27,7 +27,6 @@
#include <linux/mutex.h>
#include <linux/mfd/ucb1x00.h>
#include <linux/gpio.h>
#include <linux/semaphore.h>
static DEFINE_MUTEX(ucb1x00_mutex);
static LIST_HEAD(ucb1x00_drivers);
@ -99,7 +98,7 @@ void ucb1x00_io_write(struct ucb1x00 *ucb, unsigned int set, unsigned int clear)
* ucb1x00_enable must have been called to enable the comms
* before using this function.
*
* This function does not take any semaphores or spinlocks.
* This function does not take any mutexes or spinlocks.
*/
unsigned int ucb1x00_io_read(struct ucb1x00 *ucb)
{
@ -183,7 +182,7 @@ static int ucb1x00_gpio_direction_output(struct gpio_chip *chip, unsigned offset
* Any code wishing to use the ADC converter must call this
* function prior to using it.
*
* This function takes the ADC semaphore to prevent two or more
* This function takes the ADC mutex to prevent two or more
* concurrent uses, and therefore may sleep. As a result, it
* can only be called from process context, not interrupt
* context.
@ -193,7 +192,7 @@ static int ucb1x00_gpio_direction_output(struct gpio_chip *chip, unsigned offset
*/
void ucb1x00_adc_enable(struct ucb1x00 *ucb)
{
down(&ucb->adc_sem);
mutex_lock(&ucb->adc_mutex);
ucb->adc_cr |= UCB_ADC_ENA;
@ -215,7 +214,7 @@ void ucb1x00_adc_enable(struct ucb1x00 *ucb)
* complete (2 frames max without sync).
*
* If called for a synchronised ADC conversion, it may sleep
* with the ADC semaphore held.
* with the ADC mutex held.
*/
unsigned int ucb1x00_adc_read(struct ucb1x00 *ucb, int adc_channel, int sync)
{
@ -243,7 +242,7 @@ unsigned int ucb1x00_adc_read(struct ucb1x00 *ucb, int adc_channel, int sync)
* ucb1x00_adc_disable - disable the ADC converter
* @ucb: UCB1x00 structure describing chip
*
* Disable the ADC converter and release the ADC semaphore.
* Disable the ADC converter and release the ADC mutex.
*/
void ucb1x00_adc_disable(struct ucb1x00 *ucb)
{
@ -251,7 +250,7 @@ void ucb1x00_adc_disable(struct ucb1x00 *ucb)
ucb1x00_reg_write(ucb, UCB_ADC_CR, ucb->adc_cr);
ucb1x00_disable(ucb);
up(&ucb->adc_sem);
mutex_unlock(&ucb->adc_mutex);
}
/*
@ -560,7 +559,7 @@ static int ucb1x00_probe(struct mcp *mcp)
spin_lock_init(&ucb->lock);
spin_lock_init(&ucb->io_lock);
sema_init(&ucb->adc_sem, 1);
mutex_init(&ucb->adc_mutex);
ucb->id = id;
ucb->mcp = mcp;

4
include/linux/mfd/ucb1x00.h
View File

@ -12,7 +12,7 @@
#include <linux/mfd/mcp.h>
#include <linux/gpio.h>
#include <linux/semaphore.h>
#include <linux/mutex.h>
#define UCB_IO_DATA 0x00
#define UCB_IO_DIR 0x01
@ -124,7 +124,7 @@ struct ucb1x00 {
spinlock_t lock;
struct mcp *mcp;
unsigned int irq;
struct semaphore adc_sem;
struct mutex adc_mutex;
spinlock_t io_lock;
u16 id;
u16 io_dir;