[PATCH 14/22] usb: phy: twl4030-usb: Use mutex instead of spinlock for protecting the data

From: Kishon Vijay Abraham I
Date: Wed Sep 24 2014 - 09:48:09 EST


From: Tony Lindgren <tony@xxxxxxxxxxx>

We're using threaded irq on a I2C bus and we're sleeping in
twl4030_usb_irq() as it calls twl4030_usb_linkstat() which
calls the i2c functions. If we ever need to lock for longer
I2C transaction sequences a mutex will allow us to do that
easily.

Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
drivers/phy/phy-twl4030-usb.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c
index 24ff3c6..1e0e2d1 100644
--- a/drivers/phy/phy-twl4030-usb.c
+++ b/drivers/phy/phy-twl4030-usb.c
@@ -28,7 +28,6 @@
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
-#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/io.h>
#include <linux/delay.h>
@@ -155,7 +154,7 @@ struct twl4030_usb {
struct regulator *usb3v1;

/* for vbus reporting with irqs disabled */
- spinlock_t lock;
+ struct mutex lock;

/* pin configuration */
enum twl4030_usb_mode usb_mode;
@@ -516,13 +515,12 @@ static ssize_t twl4030_usb_vbus_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct twl4030_usb *twl = dev_get_drvdata(dev);
- unsigned long flags;
int ret = -EINVAL;

- spin_lock_irqsave(&twl->lock, flags);
+ mutex_lock(&twl->lock);
ret = sprintf(buf, "%s\n",
twl->vbus_supplied ? "on" : "off");
- spin_unlock_irqrestore(&twl->lock, flags);
+ mutex_unlock(&twl->lock);

return ret;
}
@@ -536,12 +534,12 @@ static irqreturn_t twl4030_usb_irq(int irq, void *_twl)

status = twl4030_usb_linkstat(twl);

- spin_lock_irq(&twl->lock);
+ mutex_lock(&twl->lock);
if (status >= 0 && status != twl->linkstat) {
twl->linkstat = status;
status_changed = true;
}
- spin_unlock_irq(&twl->lock);
+ mutex_unlock(&twl->lock);

if (status_changed) {
/* FIXME add a set_power() method so that B-devices can
@@ -695,8 +693,8 @@ static int twl4030_usb_probe(struct platform_device *pdev)
if (IS_ERR(phy_provider))
return PTR_ERR(phy_provider);

- /* init spinlock for workqueue */
- spin_lock_init(&twl->lock);
+ /* init mutex for workqueue */
+ mutex_init(&twl->lock);

INIT_DELAYED_WORK(&twl->id_workaround_work, twl4030_id_workaround_work);

--
1.7.9.5

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