drm/i2c: tda998x: check more I/O errors
This patch adds more error checking inn I2C I/O functions.
In case of I/O error, this permits to avoid writing in bad controller
pages, a bad chipset detection or looping when getting the EDID.
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 7df73ba..9bd336c 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -363,7 +363,7 @@
return 0;
}
-static void
+static int
set_page(struct tda998x_priv *priv, uint16_t reg)
{
if (REG2PAGE(reg) != priv->current_page) {
@@ -372,11 +372,14 @@
REG_CURPAGE, REG2PAGE(reg)
};
int ret = i2c_master_send(client, buf, sizeof(buf));
- if (ret < 0)
+ if (ret < 0) {
dev_err(&client->dev, "Error %d writing to REG_CURPAGE\n", ret);
+ return ret;
+ }
priv->current_page = REG2PAGE(reg);
}
+ return 0;
}
static int
@@ -386,7 +389,9 @@
uint8_t addr = REG2ADDR(reg);
int ret;
- set_page(priv, reg);
+ ret = set_page(priv, reg);
+ if (ret < 0)
+ return ret;
ret = i2c_master_send(client, &addr, sizeof(addr));
if (ret < 0)
@@ -413,18 +418,24 @@
buf[0] = REG2ADDR(reg);
memcpy(&buf[1], p, cnt);
- set_page(priv, reg);
+ ret = set_page(priv, reg);
+ if (ret < 0)
+ return;
ret = i2c_master_send(client, buf, cnt + 1);
if (ret < 0)
dev_err(&client->dev, "Error %d writing to 0x%x\n", ret, reg);
}
-static uint8_t
+static int
reg_read(struct tda998x_priv *priv, uint16_t reg)
{
uint8_t val = 0;
- reg_read_range(priv, reg, &val, sizeof(val));
+ int ret;
+
+ ret = reg_read_range(priv, reg, &val, sizeof(val));
+ if (ret < 0)
+ return ret;
return val;
}
@@ -435,7 +446,9 @@
uint8_t buf[] = {REG2ADDR(reg), val};
int ret;
- set_page(priv, reg);
+ ret = set_page(priv, reg);
+ if (ret < 0)
+ return;
ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
if (ret < 0)
@@ -449,7 +462,9 @@
uint8_t buf[] = {REG2ADDR(reg), val >> 8, val};
int ret;
- set_page(priv, reg);
+ ret = set_page(priv, reg);
+ if (ret < 0)
+ return;
ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
if (ret < 0)
@@ -459,13 +474,21 @@
static void
reg_set(struct tda998x_priv *priv, uint16_t reg, uint8_t val)
{
- reg_write(priv, reg, reg_read(priv, reg) | val);
+ int old_val;
+
+ old_val = reg_read(priv, reg);
+ if (old_val >= 0)
+ reg_write(priv, reg, old_val | val);
}
static void
reg_clear(struct tda998x_priv *priv, uint16_t reg, uint8_t val)
{
- reg_write(priv, reg, reg_read(priv, reg) & ~val);
+ int old_val;
+
+ old_val = reg_read(priv, reg);
+ if (old_val >= 0)
+ reg_write(priv, reg, old_val & ~val);
}
static void
@@ -978,8 +1001,10 @@
/* wait for block read to complete: */
for (i = 100; i > 0; i--) {
- uint8_t val = reg_read(priv, REG_INT_FLAGS_2);
- if (val & INT_FLAGS_2_EDID_BLK_RD)
+ ret = reg_read(priv, REG_INT_FLAGS_2);
+ if (ret < 0)
+ return ret;
+ if (ret & INT_FLAGS_2_EDID_BLK_RD)
break;
msleep(1);
}
@@ -1144,6 +1169,7 @@
struct drm_encoder_slave *encoder_slave)
{
struct tda998x_priv *priv;
+ int ret;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -1172,8 +1198,11 @@
tda998x_reset(priv);
/* read version: */
- priv->rev = reg_read(priv, REG_VERSION_LSB) |
- reg_read(priv, REG_VERSION_MSB) << 8;
+ ret = reg_read(priv, REG_VERSION_LSB) |
+ (reg_read(priv, REG_VERSION_MSB) << 8);
+ if (ret < 0)
+ goto fail;
+ priv->rev = ret;
/* mask off feature bits: */
priv->rev &= ~0x30; /* not-hdcp and not-scalar bit */