diff options
| author | Leilk.Liu <leilk.liu@mediatek.com> | 2025-09-06 16:24:06 +0800 |
|---|---|---|
| committer | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2025-09-25 23:14:59 +0200 |
| commit | b492183652808e0f389272bf63dc836241b287ff (patch) | |
| tree | 15b5333c4c555a54c2c26bc3d70f56ab8a5d6e31 /drivers/i2c | |
| parent | 1a2b423be6a89dd07d5fc27ea042be68697a6a49 (diff) | |
i2c: mediatek: fix potential incorrect use of I2C_MASTER_WRRD
The old IC does not support the I2C_MASTER_WRRD (write-then-read)
function, but the current code’s handling of i2c->auto_restart may
potentially lead to entering the I2C_MASTER_WRRD software flow,
resulting in unexpected bugs.
Instead of repurposing the auto_restart flag, add a separate flag
to signal I2C_MASTER_WRRD operations.
Also fix handling of msgs. If the operation (i2c->op) is
I2C_MASTER_WRRD, then the msgs pointer is incremented by 2.
For all other operations, msgs is simply incremented by 1.
Fixes: b2ed11e224a2 ("I2C: mediatek: Add driver for MediaTek MT8173 I2C controller")
Signed-off-by: Leilk.Liu <leilk.liu@mediatek.com>
Suggested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-mt65xx.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index ab456c3717db..dee40704825c 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -1243,6 +1243,7 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, { int ret; int left_num = num; + bool write_then_read_en = false; struct mtk_i2c *i2c = i2c_get_adapdata(adap); ret = clk_bulk_enable(I2C_MT65XX_CLK_MAX, i2c->clocks); @@ -1256,6 +1257,7 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD) && msgs[0].addr == msgs[1].addr) { i2c->auto_restart = 0; + write_then_read_en = true; } } @@ -1280,12 +1282,10 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, else i2c->op = I2C_MASTER_WR; - if (!i2c->auto_restart) { - if (num > 1) { - /* combined two messages into one transaction */ - i2c->op = I2C_MASTER_WRRD; - left_num--; - } + if (write_then_read_en) { + /* combined two messages into one transaction */ + i2c->op = I2C_MASTER_WRRD; + left_num--; } /* always use DMA mode. */ @@ -1293,7 +1293,10 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, if (ret < 0) goto err_exit; - msgs++; + if (i2c->op == I2C_MASTER_WRRD) + msgs += 2; + else + msgs++; } /* the return value is number of executed messages */ ret = num; |