From abf4923e97c3abbbd1e59f0e13c7c214c93c6aaa Mon Sep 17 00:00:00 2001 From: Hsin-Yi Wang Date: Thu, 22 Aug 2019 17:45:17 +0800 Subject: [PATCH] i2c: mediatek: disable zero-length transfers for mt8183 Quoting from mt8183 datasheet, the number of transfers to be transferred in one transaction should be set to bigger than 1, so we should forbid zero-length transfer and update functionality. Reported-by: Alexandru M Stan Signed-off-by: Hsin-Yi Wang Reviewed-by: Qii Wang [wsa: shortened commit message a little] Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-mt65xx.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index 252edb433fdf..29eae1bf4f86 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -234,6 +234,10 @@ static const struct i2c_adapter_quirks mt7622_i2c_quirks = { .max_num_msgs = 255, }; +static const struct i2c_adapter_quirks mt8183_i2c_quirks = { + .flags = I2C_AQ_NO_ZERO_LEN, +}; + static const struct mtk_i2c_compatible mt2712_compat = { .regs = mt_i2c_regs_v1, .pmic_i2c = 0, @@ -298,6 +302,7 @@ static const struct mtk_i2c_compatible mt8173_compat = { }; static const struct mtk_i2c_compatible mt8183_compat = { + .quirks = &mt8183_i2c_quirks, .regs = mt_i2c_regs_v2, .pmic_i2c = 0, .dcm = 0, @@ -870,7 +875,11 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id) static u32 mtk_i2c_functionality(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; + if (adap->quirks->flags & I2C_AQ_NO_ZERO_LEN) + return I2C_FUNC_I2C | + (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); + else + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm mtk_i2c_algorithm = { -- 2.11.0