One thing I missed from Matthias' comment on v4: https://patchwork.kernel.org/patch/10822083/ On Wed, Mar 6, 2019 at 6:44 PM Nicolas Boichat <drinkcat@xxxxxxxxxxxx> wrote: > > On Tue, Feb 26, 2019 at 9:11 PM Qii Wang <qii.wang@xxxxxxxxxxxx> wrote: > > > > When two i2c controllers are internally connected to the same > > GPIO pins, the arb clock is needed to ensure that the waveforms > > do not interfere with each other. > > > > Signed-off-by: Qii Wang <qii.wang@xxxxxxxxxxxx> > > Reviewed-by: Nicolas Boichat <drinkcat@xxxxxxxxxxxx> > > > --- > > drivers/i2c/busses/i2c-mt65xx.c | 25 ++++++++++++++++++++++--- > > 1 file changed, 22 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c > > index 428ac99..14d6b38 100644 > > --- a/drivers/i2c/busses/i2c-mt65xx.c > > +++ b/drivers/i2c/busses/i2c-mt65xx.c > > @@ -35,6 +35,7 @@ > > #include <linux/slab.h> > > > > #define I2C_RS_TRANSFER (1 << 4) > > +#define I2C_ARB_LOST (1 << 3) > > #define I2C_HS_NACKERR (1 << 2) > > #define I2C_ACKERR (1 << 1) > > #define I2C_TRANSAC_COMP (1 << 0) > > @@ -181,6 +182,7 @@ struct mtk_i2c { > > struct clk *clk_main; /* main clock for i2c bus */ > > struct clk *clk_dma; /* DMA clock for i2c via DMA */ > > struct clk *clk_pmic; /* PMIC clock for i2c from PMIC */ > > + struct clk *clk_arb; /* Arbitrator clock for i2c */ > > bool have_pmic; /* can use i2c pins from PMIC */ > > bool use_push_pull; /* IO config push-pull mode */ > > > > @@ -299,8 +301,18 @@ static int mtk_i2c_clock_enable(struct mtk_i2c *i2c) > > if (ret) > > goto err_pmic; > > } > > + > > + if (i2c->clk_arb) { > > + ret = clk_prepare_enable(i2c->clk_arb); > > + if (ret) > > + goto err_arb; > > + } > > + > > return 0; > > > > +err_arb: > > + if (i2c->have_pmic) > > + clk_disable_unprepare(i2c->clk_pmic); > > err_pmic: > > clk_disable_unprepare(i2c->clk_main); > > err_main: > > @@ -311,6 +323,9 @@ static int mtk_i2c_clock_enable(struct mtk_i2c *i2c) > > > > static void mtk_i2c_clock_disable(struct mtk_i2c *i2c) > > { > > + if (i2c->clk_arb) > > + clk_disable_unprepare(i2c->clk_arb); > > + > > if (i2c->have_pmic) > > clk_disable_unprepare(i2c->clk_pmic); > > > > @@ -519,13 +534,13 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs, > > > > /* Clear interrupt status */ > > mtk_i2c_writew(i2c, restart_flag | I2C_HS_NACKERR | I2C_ACKERR | > > - I2C_TRANSAC_COMP, OFFSET_INTR_STAT); > > + I2C_ARB_LOST | I2C_TRANSAC_COMP, OFFSET_INTR_STAT); Is it ok to set I2C_ARB_LOST on _all_ SoC that this driver supports? If so, please at least say so in the commit message. > > > > mtk_i2c_writew(i2c, I2C_FIFO_ADDR_CLR, OFFSET_FIFO_ADDR_CLR); > > > > /* Enable interrupt */ > > mtk_i2c_writew(i2c, restart_flag | I2C_HS_NACKERR | I2C_ACKERR | > > - I2C_TRANSAC_COMP, OFFSET_INTR_MASK); > > + I2C_ARB_LOST | I2C_TRANSAC_COMP, OFFSET_INTR_MASK); > > > > /* Set transfer and transaction len */ > > if (i2c->op == I2C_MASTER_WRRD) { > > @@ -659,7 +674,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs, > > > > /* Clear interrupt mask */ > > mtk_i2c_writew(i2c, ~(restart_flag | I2C_HS_NACKERR | I2C_ACKERR | > > - I2C_TRANSAC_COMP), OFFSET_INTR_MASK); > > + I2C_ARB_LOST | I2C_TRANSAC_COMP), OFFSET_INTR_MASK); > > > > if (i2c->op == I2C_MASTER_WR) { > > dma_unmap_single(i2c->dev, wpaddr, > > @@ -884,6 +899,10 @@ static int mtk_i2c_probe(struct platform_device *pdev) > > return PTR_ERR(i2c->clk_dma); > > } > > > > + i2c->clk_arb = devm_clk_get(&pdev->dev, "arb"); > > + if (IS_ERR(i2c->clk_arb)) > > + i2c->clk_arb = NULL; > > + > > clk = i2c->clk_main; > > if (i2c->have_pmic) { > > i2c->clk_pmic = devm_clk_get(&pdev->dev, "pmic"); > > -- > > 1.7.9.5 > >
