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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>
This commit is contained in:
Jean-Francois Moine 2014-01-25 18:14:45 +01:00 committed by Russell King
parent 2f7f730a4f
commit 7d2eadc9b9
1 changed files with 43 additions and 14 deletions
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57
drivers/gpu/drm/i2c/tda998x_drv.c
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@ -363,7 +363,7 @@ cec_read(struct tda998x_priv *priv, uint8_t addr)
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 @@ 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
@ -386,7 +389,9 @@ 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)
@ -413,18 +418,24 @@ 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;
}
@ -435,7 +446,9 @@ 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)
@ -449,7 +462,9 @@ 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)
@ -459,13 +474,21 @@ 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
@ -978,8 +1001,10 @@ 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);
}
@ -1144,6 +1169,7 @@ 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)
@ -1172,8 +1198,11 @@ 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 */