drm: tda998x: Protect the page register

As the HDMI registers of the TDA998x chips are accessed by pages,
the page register must be protected.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 20 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index d4762799351d..6795f094f737 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -32,6 +32,7 @@
 struct tda998x_priv {
         struct i2c_client *cec;
         struct i2c_client *hdmi;
+        struct mutex mutex;
         uint16_t rev;
         uint8_t current_page;
         int dpms;
@@ -402,9 +403,10 @@ reg_read_range(struct tda998x_priv *priv, uint16_t reg, char *buf, int cnt)
         uint8_t addr = REG2ADDR(reg);
         int ret;
 
+        mutex_lock(&priv->mutex);
         ret = set_page(priv, reg);
         if (ret < 0)
-                return ret;
+                goto out;
 
         ret = i2c_master_send(client, &addr, sizeof(addr));
         if (ret < 0)
@@ -414,10 +416,12 @@ reg_read_range(struct tda998x_priv *priv, uint16_t reg, char *buf, int cnt)
         if (ret < 0)
                 goto fail;
 
-        return ret;
+        goto out;
 
 fail:
         dev_err(&client->dev, "Error %d reading from 0x%x\n", ret, reg);
+out:
+        mutex_unlock(&priv->mutex);
         return ret;
 }
 
@@ -431,13 +435,16 @@ reg_write_range(struct tda998x_priv *priv, uint16_t reg, uint8_t *p, int cnt)
         buf[0] = REG2ADDR(reg);
         memcpy(&buf[1], p, cnt);
 
+        mutex_lock(&priv->mutex);
         ret = set_page(priv, reg);
         if (ret < 0)
-                return;
+                goto out;
 
         ret = i2c_master_send(client, buf, cnt + 1);
         if (ret < 0)
                 dev_err(&client->dev, "Error %d writing to 0x%x\n", ret, reg);
+out:
+        mutex_unlock(&priv->mutex);
 }
 
 static int
@@ -459,13 +466,16 @@ reg_write(struct tda998x_priv *priv, uint16_t reg, uint8_t val)
         uint8_t buf[] = {REG2ADDR(reg), val};
         int ret;
 
+        mutex_lock(&priv->mutex);
         ret = set_page(priv, reg);
         if (ret < 0)
-                return;
+                goto out;
 
         ret = i2c_master_send(client, buf, sizeof(buf));
         if (ret < 0)
                 dev_err(&client->dev, "Error %d writing to 0x%x\n", ret, reg);
+out:
+        mutex_unlock(&priv->mutex);
 }
 
 static void
@@ -475,13 +485,16 @@ reg_write16(struct tda998x_priv *priv, uint16_t reg, uint16_t val)
         uint8_t buf[] = {REG2ADDR(reg), val >> 8, val};
         int ret;
 
+        mutex_lock(&priv->mutex);
         ret = set_page(priv, reg);
         if (ret < 0)
-                return;
+                goto out;
 
         ret = i2c_master_send(client, buf, sizeof(buf));
         if (ret < 0)
                 dev_err(&client->dev, "Error %d writing to 0x%x\n", ret, reg);
+out:
+        mutex_unlock(&priv->mutex);
 }
 
 static void
@@ -1268,6 +1281,8 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
 
         priv->dpms = DRM_MODE_DPMS_OFF;
 
+        mutex_init(&priv->mutex);       /* protect the page access */
+
         /* wake up the device: */
         cec_write(priv, REG_CEC_ENAMODS,
                         CEC_ENAMODS_EN_RXSENS | CEC_ENAMODS_EN_HDMI);