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>

4 files changed, 17 insertions, 2 deletions

diff --git a/drivers/media/video/cx18/cx18-driver.c b/drivers/media/video/cx18/cx18-driver.c
index e73de625225..22434aadde3 100644
--- a/drivers/media/video/cx18/cx18-driver.c
+++ b/drivers/media/video/cx18/cx18-driver.c
@@ -421,6 +421,7 @@ static int __devinit cx18_init_struct1(struct cx18 *cx)
         mutex_init(&cx->serialize_lock);
         mutex_init(&cx->i2c_bus_lock[0]);
         mutex_init(&cx->i2c_bus_lock[1]);
+        mutex_init(&cx->gpio_lock);
 
         spin_lock_init(&cx->lock);
         spin_lock_init(&cx->dma_reg_lock);
diff --git a/drivers/media/video/cx18/cx18-driver.h b/drivers/media/video/cx18/cx18-driver.h
index b78d0e38d53..45e31b04730 100644
--- a/drivers/media/video/cx18/cx18-driver.h
+++ b/drivers/media/video/cx18/cx18-driver.h
@@ -427,6 +427,7 @@ struct cx18 {
         /* gpio */
         u32 gpio_dir;
         u32 gpio_val;
+        struct mutex gpio_lock;
 
         /* v4l2 and User settings */
 
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;
 }
diff --git a/drivers/media/video/cx18/cx18-ioctl.c b/drivers/media/video/cx18/cx18-ioctl.c
index 6eaf77b99e9..146a4b85649 100644
--- a/drivers/media/video/cx18/cx18-ioctl.c
+++ b/drivers/media/video/cx18/cx18-ioctl.c
@@ -716,8 +716,10 @@ static int cx18_log_status(struct file *file, void *fh)
         cx18_get_audio_input(cx, cx->audio_input, &audin);
         CX18_INFO("Video Input: %s\n", vidin.name);
         CX18_INFO("Audio Input: %s\n", audin.name);
+        mutex_lock(&cx->gpio_lock);
         CX18_INFO("GPIO:  direction 0x%08x, value 0x%08x\n",
                 cx->gpio_dir, cx->gpio_val);
+        mutex_unlock(&cx->gpio_lock);
         CX18_INFO("Tuner: %s\n",
                 test_bit(CX18_F_I_RADIO_USER, &cx->i_flags) ?  "Radio" : "TV");
         cx2341x_log_status(&cx->params, cx->name);