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 at arm.linux.org.uk>
Signed-off-by: Jean-Francois Moine <moinejf at free.fr>
---
drivers/gpu/drm/i2c/tda998x_drv.c | 57 +++++++++++++++++++++++++++++----------
1 file changed, 43 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 26dd299..11f0607 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -362,7 +362,7 @@ fail:
return 0;
}
-static void
+static int
set_page(struct tda998x_priv *priv, uint16_t reg)
{
if (REG2PAGE(reg) != priv->current_page) {
@@ -371,11 +371,14 @@ set_page(struct tda998x_priv *priv, uint16_t reg)
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
@@ -385,7 +388,9 @@ reg_read_range(struct tda998x_priv *priv, uint16_t reg, char *buf, int cnt)
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)
@@ -412,18 +417,24 @@ reg_write_range(struct tda998x_priv *priv, uint16_t reg, uint8_t *p, int cnt)
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;
}
@@ -434,7 +445,9 @@ reg_write(struct tda998x_priv *priv, uint16_t reg, uint8_t val)
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)
@@ -448,7 +461,9 @@ reg_write16(struct tda998x_priv *priv, uint16_t reg, uint16_t val)
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)
@@ -458,13 +473,21 @@ reg_write16(struct tda998x_priv *priv, uint16_t reg, uint16_t val)
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
@@ -970,8 +993,10 @@ read_edid_block(struct drm_encoder *encoder, uint8_t *buf, int blk)
/* 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);
}
@@ -1134,6 +1159,7 @@ tda998x_encoder_init(struct i2c_client *client,
struct drm_encoder_slave *encoder_slave)
{
struct tda998x_priv *priv;
+ int ret;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -1158,8 +1184,11 @@ tda998x_encoder_init(struct i2c_client *client,
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 */
--
1.8.5.3