by Qii Wang (王琪)

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Subject: Re: [PATCH v4 3/3] i2c: mediatek: Add i2c support for MediaTek MT8183

I am sorry to have missed some comment, and reply the mail again.

On Wed, 2019-02-20 at 15:41 +0100, Matthias Brugger wrote:
>
> On 20/02/2019 13:33, Qii Wang wrote:
> > Add i2c compatible for MT8183. Compare to MT2712 i2c controller,
> > MT8183 has different registers, offsets and clock.
> >
> > Signed-off-by: Qii Wang <[email protected]>
>
> So you introduce arb clock, ltiming (what is this exactly) and the new SoC in
> one commit. I'd prefer to split that up and explain shortly in the commit
> message why they are needed. More comments inline.
>

I have split this patch into three in V5.

> > ---
> > drivers/i2c/busses/i2c-mt65xx.c | 89 ++++++++++++++++++++++++++++++++++++---
> > 1 file changed, 84 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> > index 428ac99..82eedbd 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)
> > @@ -76,6 +77,8 @@
> > #define I2C_CONTROL_DIR_CHANGE (0x1 << 4)
> > #define I2C_CONTROL_ACKERR_DET_EN (0x1 << 5)
> > #define I2C_CONTROL_TRANSFER_LEN_CHANGE (0x1 << 6)
> > +#define I2C_CONTROL_DMAACK_EN (0x1 << 8)
> > +#define I2C_CONTROL_ASYNC_MODE (0x1 << 9)
> > #define I2C_CONTROL_WRAPPER (0x1 << 0)
> >
> > #define I2C_DRV_NAME "i2c-mt65xx"
> > @@ -130,6 +133,8 @@ enum I2C_REGS_OFFSET {
> > OFFSET_DEBUGCTRL,
> > OFFSET_TRANSFER_LEN_AUX,
> > OFFSET_CLOCK_DIV,
> > + /* MT8183 only regs */
> > + OFFSET_LTIMING,
> > };
> >
> > static const u16 mt_i2c_regs_v1[] = {
> > @@ -159,6 +164,32 @@ enum I2C_REGS_OFFSET {
> > [OFFSET_CLOCK_DIV] = 0x70,
> > };
> >
> > +static const u16 mt_i2c_regs_v2[] = {
> > + [OFFSET_DATA_PORT] = 0x0,
> > + [OFFSET_SLAVE_ADDR] = 0x4,
> > + [OFFSET_INTR_MASK] = 0x8,
> > + [OFFSET_INTR_STAT] = 0xc,
> > + [OFFSET_CONTROL] = 0x10,
> > + [OFFSET_TRANSFER_LEN] = 0x14,
> > + [OFFSET_TRANSAC_LEN] = 0x18,
> > + [OFFSET_DELAY_LEN] = 0x1c,
> > + [OFFSET_TIMING] = 0x20,
> > + [OFFSET_START] = 0x24,
> > + [OFFSET_EXT_CONF] = 0x28,
> > + [OFFSET_LTIMING] = 0x2c,
> > + [OFFSET_HS] = 0x30,
> > + [OFFSET_IO_CONFIG] = 0x34,
> > + [OFFSET_FIFO_ADDR_CLR] = 0x38,
> > + [OFFSET_TRANSFER_LEN_AUX] = 0x44,
> > + [OFFSET_CLOCK_DIV] = 0x48,
> > + [OFFSET_SOFTRESET] = 0x50,
> > + [OFFSET_DEBUGSTAT] = 0xe0,
> > + [OFFSET_DEBUGCTRL] = 0xe8,
> > + [OFFSET_FIFO_STAT] = 0xf4,
> > + [OFFSET_FIFO_THRESH] = 0xf8,
> > + [OFFSET_DCM_EN] = 0xf88,
> > +};
> > +
> > struct mtk_i2c_compatible {
> > const struct i2c_adapter_quirks *quirks;
> > const u16 *regs;
> > @@ -168,6 +199,7 @@ struct mtk_i2c_compatible {
> > unsigned char aux_len_reg: 1;
> > unsigned char support_33bits: 1;
> > unsigned char timing_adjust: 1;
> > + unsigned char dma_sync: 1;
> > };
> >
> > struct mtk_i2c {
> > @@ -181,6 +213,7 @@ 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 */
> >
> > @@ -190,6 +223,7 @@ struct mtk_i2c {
> > enum mtk_trans_op op;
> > u16 timing_reg;
> > u16 high_speed_reg;
> > + u16 ltiming_reg;
> > unsigned char auto_restart;
> > bool ignore_restart_irq;
> > const struct mtk_i2c_compatible *dev_comp;
> > @@ -216,6 +250,7 @@ struct mtk_i2c {
> > .aux_len_reg = 1,
> > .support_33bits = 1,
> > .timing_adjust = 1,
> > + .dma_sync = 0,
> > };
> >
> > static const struct mtk_i2c_compatible mt6577_compat = {
> > @@ -227,6 +262,7 @@ struct mtk_i2c {
> > .aux_len_reg = 0,
> > .support_33bits = 0,
> > .timing_adjust = 0,
> > + .dma_sync = 0,
> > };
> >
> > static const struct mtk_i2c_compatible mt6589_compat = {
> > @@ -238,6 +274,7 @@ struct mtk_i2c {
> > .aux_len_reg = 0,
> > .support_33bits = 0,
> > .timing_adjust = 0,
> > + .dma_sync = 0,
> > };
> >
> > static const struct mtk_i2c_compatible mt7622_compat = {
> > @@ -249,6 +286,7 @@ struct mtk_i2c {
> > .aux_len_reg = 1,
> > .support_33bits = 0,
> > .timing_adjust = 0,
> > + .dma_sync = 0,
> > };
> >
> > static const struct mtk_i2c_compatible mt8173_compat = {
> > @@ -259,6 +297,18 @@ struct mtk_i2c {
> > .aux_len_reg = 1,
> > .support_33bits = 1,
> > .timing_adjust = 0,
> > + .dma_sync = 0,
> > +};
> > +
> > +static const struct mtk_i2c_compatible mt8183_compat = {
> > + .regs = mt_i2c_regs_v2,
> > + .pmic_i2c = 0,
> > + .dcm = 0,
> > + .auto_restart = 1,
> > + .aux_len_reg = 1,
> > + .support_33bits = 1,
> > + .timing_adjust = 1,
> > + .dma_sync = 1,
> > };
> >
> > static const struct of_device_id mtk_i2c_of_match[] = {
> > @@ -267,6 +317,7 @@ struct mtk_i2c {
> > { .compatible = "mediatek,mt6589-i2c", .data = &mt6589_compat },
> > { .compatible = "mediatek,mt7622-i2c", .data = &mt7622_compat },
> > { .compatible = "mediatek,mt8173-i2c", .data = &mt8173_compat },
> > + { .compatible = "mediatek,mt8183-i2c", .data = &mt8183_compat },
> > {}
> > };
> > MODULE_DEVICE_TABLE(of, mtk_i2c_of_match);
> > @@ -299,8 +350,18 @@ 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 +372,9 @@ 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);
> >
> > @@ -338,6 +402,8 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
> >
> > mtk_i2c_writew(i2c, i2c->timing_reg, OFFSET_TIMING);
> > mtk_i2c_writew(i2c, i2c->high_speed_reg, OFFSET_HS);
> > + if (i2c->dev_comp->regs == mt_i2c_regs_v2)
>
> I'm not really happy with this check. I personally would prefer a flag or
> something which shows that we need ltiming.
>

ok, I will add a flag(ltiming_adjust) in mtk_i2c_compatible.

> > + mtk_i2c_writew(i2c, i2c->ltiming_reg, OFFSET_LTIMING);
> >
> > /* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
> > if (i2c->have_pmic)
> > @@ -345,6 +411,9 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
> >
> > control_reg = I2C_CONTROL_ACKERR_DET_EN |
> > I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
> > + if (i2c->dev_comp->dma_sync)
> > + control_reg |= I2C_CONTROL_DMAACK_EN | I2C_CONTROL_ASYNC_MODE;
> > +
> > mtk_i2c_writew(i2c, control_reg, OFFSET_CONTROL);
> > mtk_i2c_writew(i2c, I2C_DELAY_LEN, OFFSET_DELAY_LEN);
> >
> > @@ -434,6 +503,8 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> > unsigned int clk_src;
> > unsigned int step_cnt;
> > unsigned int sample_cnt;
> > + unsigned int l_step_cnt;
> > + unsigned int l_sample_cnt;
> > unsigned int target_speed;
> > int ret;
> >
> > @@ -443,11 +514,11 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> > if (target_speed > MAX_FS_MODE_SPEED) {
> > /* Set master code speed register */
> > ret = mtk_i2c_calculate_speed(i2c, clk_src, MAX_FS_MODE_SPEED,
> > - &step_cnt, &sample_cnt);
> > + &l_step_cnt, &l_sample_cnt);
> > if (ret < 0)
> > return ret;
> >
> > - i2c->timing_reg = (sample_cnt << 8) | step_cnt;
> > + i2c->timing_reg = (l_sample_cnt << 8) | l_step_cnt;
> >
> > /* Set the high speed mode register */
> > ret = mtk_i2c_calculate_speed(i2c, clk_src, target_speed,
> > @@ -457,6 +528,8 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> >
> > i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
> > (sample_cnt << 12) | (step_cnt << 8);
> > + i2c->ltiming_reg = (l_sample_cnt << 6) | l_step_cnt |
> > + (sample_cnt << 12) | (step_cnt << 9);
>
> IMHO setting these for all SoCs but then only using it for one makes things more
> complicated. Value should only be set for SoCs that need this features.
>

ok, I will set it dependent on ltiming_adjust.

> > } else {
> > ret = mtk_i2c_calculate_speed(i2c, clk_src, target_speed,
> > &step_cnt, &sample_cnt);
> > @@ -467,6 +540,8 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> >
> > /* Disable the high speed transaction */
> > i2c->high_speed_reg = I2C_TIME_CLR_VALUE;
> > +
> > + i2c->ltiming_reg = (sample_cnt << 6) | step_cnt;
> > }
> >
> > return 0;
> > @@ -519,13 +594,13 @@ 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);
>
> Did you test that this works with all the old SoCs that are already supported by
> this driver?
>
> Regards,
> Matthias
>

Yes, old SoCs also have the bit(I2C_ARB_LOST), but there was no need for
multi-master before, so we didn't set it up specifically.

> >
> > 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 +734,7 @@ 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 +959,10 @@ 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");
> >