On Mon, Feb 15, 2021 at 08:03:21PM +0100, Mårten Lindahl wrote: > From: Mårten Lindahl <martenli@xxxxxxxx> > > When the controller starts to send a message with the MASTER_ID field > set (high speed), the whole I2C_ADDR register is overwritten including > MASTER_ID as the SLV_ADDR_MAS field is set. Are you here describing bug in driver or hardware (the controller?)? Looking at the code, I think the driver, but description got me confused. > > This patch preserves already written fields in I2C_ADDR when writing > SLV_ADDR_MAS. > > Signed-off-by: Mårten Lindahl <martenli@xxxxxxxx> > --- > drivers/i2c/busses/i2c-exynos5.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c > index 20a9881a0d6c..f2d04c241299 100644 > --- a/drivers/i2c/busses/i2c-exynos5.c > +++ b/drivers/i2c/busses/i2c-exynos5.c > @@ -606,6 +606,7 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop) > u32 i2c_ctl; > u32 int_en = 0; > u32 i2c_auto_conf = 0; > + u32 i2c_addr = 0; > u32 fifo_ctl; > unsigned long flags; > unsigned short trig_lvl; > @@ -640,7 +641,12 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop) > int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN; > } > > - writel(HSI2C_SLV_ADDR_MAS(i2c->msg->addr), i2c->regs + HSI2C_ADDR); > + i2c_addr = HSI2C_SLV_ADDR_MAS(i2c->msg->addr); > + > + if (i2c->op_clock >= I2C_MAX_FAST_MODE_PLUS_FREQ) > + i2c_addr |= readl(i2c->regs + HSI2C_ADDR); Any reason why not "|= MASTER_ID(i2c->adap.nr)" here instead of more expensive IO read? It's quite important because your current code will bitwise-or old I2C slave address with a new one... This should break during tests with multiple I2C slave devices, shouldn't it? On which HW did you test it? Best regards, Krzysztof > + > + writel(i2c_addr, i2c->regs + HSI2C_ADDR);
