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. Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Tested-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Signed-off-by: Jean-Francois Moine <moinejf@xxxxxxx> --- 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 */ -- 1.9.rc1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel