V4L/DVB (8331): cx18: Add locking for struct cx18 GPIO state variables

cx18: Add locking for struct cx18 GPIO state variables in
anticpation of adding IR microcontroller reset support for
use by external IR modules.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/media/video/cx18/cx18-gpio.c b/drivers/media/video/cx18/cx18-gpio.c
index 089bad6d85a..d753a40973b 100644
--- a/drivers/media/video/cx18/cx18-gpio.c
+++ b/drivers/media/video/cx18/cx18-gpio.c
@@ -69,6 +69,7 @@ void cx18_reset_i2c_slaves_gpio(struct cx18 *cx)
         /* Assuming that the masks are a subset of the bits in gpio_dir */
 
         /* Assert */
+        mutex_lock(&cx->gpio_lock);
         cx->gpio_val =
                 (cx->gpio_val | p->active_hi_mask) & ~(p->active_lo_mask);
         gpio_write(cx);
@@ -79,10 +80,12 @@ void cx18_reset_i2c_slaves_gpio(struct cx18 *cx)
                 (cx->gpio_val | p->active_lo_mask) & ~(p->active_hi_mask);
         gpio_write(cx);
         schedule_timeout_uninterruptible(msecs_to_jiffies(p->msecs_recovery));
+        mutex_unlock(&cx->gpio_lock);
 }
 
 void cx18_gpio_init(struct cx18 *cx)
 {
+        mutex_lock(&cx->gpio_lock);
         cx->gpio_dir = cx->card->gpio_init.direction;
         cx->gpio_val = cx->card->gpio_init.initial_value;
 
@@ -91,14 +94,17 @@ void cx18_gpio_init(struct cx18 *cx)
                 cx->gpio_val |= 1 << cx->card->xceive_pin;
         }
 
-        if (cx->gpio_dir == 0)
+        if (cx->gpio_dir == 0) {
+                mutex_unlock(&cx->gpio_lock);
                 return;
+        }
 
         CX18_DEBUG_INFO("GPIO initial dir: %08x/%08x out: %08x/%08x\n",
                    read_reg(CX18_REG_GPIO_DIR1), read_reg(CX18_REG_GPIO_DIR2),
                    read_reg(CX18_REG_GPIO_OUT1), read_reg(CX18_REG_GPIO_OUT2));
 
         gpio_write(cx);
+        mutex_unlock(&cx->gpio_lock);
 }
 
 /* Xceive tuner reset function */
@@ -112,13 +118,16 @@ int cx18_reset_tuner_gpio(void *dev, int cmd, int value)
                 return 0;
         CX18_DEBUG_INFO("Resetting tuner\n");
 
+        mutex_lock(&cx->gpio_lock);
         cx->gpio_val &= ~(1 << cx->card->xceive_pin);
-
         gpio_write(cx);
+        mutex_unlock(&cx->gpio_lock);
         schedule_timeout_interruptible(msecs_to_jiffies(1));
 
+        mutex_lock(&cx->gpio_lock);
         cx->gpio_val |= 1 << cx->card->xceive_pin;
         gpio_write(cx);
+        mutex_unlock(&cx->gpio_lock);
         schedule_timeout_interruptible(msecs_to_jiffies(1));
         return 0;
 }
@@ -151,8 +160,10 @@ int cx18_gpio(struct cx18 *cx, unsigned int command, void *arg)
                 return -EINVAL;
         }
         if (mask) {
+                mutex_lock(&cx->gpio_lock);
                 cx->gpio_val = (cx->gpio_val & ~mask) | (data & mask);
                 gpio_write(cx);
+                mutex_unlock(&cx->gpio_lock);
         }
         return 0;
 }