[PATCH] gpu: anx7808: fix a missing check of return value

[Kangjie Lu]

Both anx78xx_set_bits() and anx78xx_clear_bits() in the poweron process
may fail. The fix inserts checks for their return values. If the poweron
process fails, it calls anx78xx_poweroff().

Signed-off-by: Kangjie Lu <k...@umn.edu>
---
 drivers/gpu/drm/bridge/analogix-anx78xx.c | 26 ++++++++++++++++-------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix-anx78xx.c 
b/drivers/gpu/drm/bridge/analogix-anx78xx.c
index f8433c93f463..a57104c71739 100644
--- a/drivers/gpu/drm/bridge/analogix-anx78xx.c
+++ b/drivers/gpu/drm/bridge/analogix-anx78xx.c
@@ -610,20 +610,20 @@ static int anx78xx_enable_interrupts(struct anx78xx 
*anx78xx)
        return 0;
 }
 
-static void anx78xx_poweron(struct anx78xx *anx78xx)
+static int anx78xx_poweron(struct anx78xx *anx78xx)
 {
        struct anx78xx_platform_data *pdata = &anx78xx->pdata;
-       int err;
+       int err = 0;
 
        if (WARN_ON(anx78xx->powered))
-               return;
+               return err;
 
        if (pdata->dvdd10) {
                err = regulator_enable(pdata->dvdd10);
                if (err) {
                        DRM_ERROR("Failed to enable DVDD10 regulator: %d\n",
                                  err);
-                       return;
+                       return err;
                }
 
                usleep_range(1000, 2000);
@@ -638,12 +638,18 @@ static void anx78xx_poweron(struct anx78xx *anx78xx)
        gpiod_set_value_cansleep(pdata->gpiod_reset, 0);
 
        /* Power on registers module */
-       anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_POWERDOWN_CTRL_REG,
+       err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], 
SP_POWERDOWN_CTRL_REG,
                         SP_HDCP_PD | SP_AUDIO_PD | SP_VIDEO_PD | SP_LINK_PD);
-       anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], SP_POWERDOWN_CTRL_REG,
+       err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], 
SP_POWERDOWN_CTRL_REG,
                           SP_REGISTER_PD | SP_TOTAL_PD);
+       if (err) { 
+               anx78xx_poweroff(anx78xx);
+               return err;
+       }
 
        anx78xx->powered = true;
+
+       return err;
 }
 
 static void anx78xx_poweroff(struct anx78xx *anx78xx)
@@ -1144,7 +1150,9 @@ static irqreturn_t anx78xx_hpd_threaded_handler(int irq, 
void *data)
        mutex_lock(&anx78xx->lock);
 
        /* Cable is pulled, power on the chip */
-       anx78xx_poweron(anx78xx);
+       err = anx78xx_poweron(anx78xx);
+       if (err)
+               DRM_ERROR("Failed to power on the chip: %d\n", err);
 
        err = anx78xx_enable_interrupts(anx78xx);
        if (err)
@@ -1379,7 +1387,9 @@ static int anx78xx_i2c_probe(struct i2c_client *client,
        }
 
        /* Look for supported chip ID */
-       anx78xx_poweron(anx78xx);
+       err = anx78xx_poweron(anx78xx);
+       if (err)
+               goto err_poweroff;
 
        err = regmap_read(anx78xx->map[I2C_IDX_TX_P2], SP_DEVICE_IDL_REG,
                          &idl);
-- 
2.17.2 (Apple Git-113)

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