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Commit cae15476 authored by Russell King's avatar Russell King
Browse files

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: default avatarJochen Friedrich <jochen@scram.de>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ddb1e04a

drivers/mfd/ucb1x00-core.c

+7 −8
Original line number Diff line number Diff line
@@ -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;

include/linux/mfd/ucb1x00.h

+2 −2
Original line number Diff line number Diff line
@@ -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;