2021-02-03 10:40:12

by Qii Wang (王琪)

Subject: [PATCH] i2c: mediatek: Get device clock-stretch time via dts

From: Qii Wang <[email protected]>

tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device
clock-stretching or circuit loss, we could get device
clock-stretch time from dts to adjust these parameters
to meet the spec via EXT_CONF register.

Signed-off-by: Qii Wang <[email protected]>
---
drivers/i2c/busses/i2c-mt65xx.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 2ffd2f3..47c7255 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -245,6 +245,7 @@ struct mtk_i2c {
u16 irq_stat; /* interrupt status */
unsigned int clk_src_div;
unsigned int speed_hz; /* The speed in transfer */
+ unsigned int clock_stretch_ns;
enum mtk_trans_op op;
u16 timing_reg;
u16 high_speed_reg;
@@ -607,7 +608,8 @@ static int mtk_i2c_check_ac_timing(struct mtk_i2c *i2c,
else
clk_ns = sample_ns / 2;

- su_sta_cnt = DIV_ROUND_UP(spec->min_su_sta_ns, clk_ns);
+ su_sta_cnt = DIV_ROUND_UP(spec->min_su_sta_ns + i2c->clock_stretch_ns,
+ clk_ns);
if (su_sta_cnt > max_sta_cnt)
return -1;

@@ -1171,6 +1173,8 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
if (i2c->clk_src_div == 0)
return -EINVAL;

+ of_property_read_u32(np, "clock-stretch-ns", &i2c->clock_stretch_ns);
+
i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
i2c->use_push_pull =
of_property_read_bool(np, "mediatek,use-push-pull");
--
1.9.1

2021-03-03 02:51:25

by Qii Wang (王琪)

Subject: Re: [PATCH] i2c: mediatek: Get device clock-stretch time via dts

Hi,
On Wed, 2021-02-03 at 18:35 +0800, [email protected] wrote:
> From: Qii Wang <[email protected]>
>
> tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device
> clock-stretching or circuit loss, we could get device
> clock-stretch time from dts to adjust these parameters
> to meet the spec via EXT_CONF register.
>
> Signed-off-by: Qii Wang <[email protected]>
> ---

Can it merge into 5.12? or do I need to resend the patch?

Thanks,
Qii

2021-03-04 06:14:08

by Ikjoon Jang

Subject: Re: [PATCH] i2c: mediatek: Get device clock-stretch time via dts

Hi Qii,

On Wed, Feb 3, 2021 at 6:43 PM <[email protected]> wrote:
>
> From: Qii Wang <[email protected]>
>
> tSU,STA/tHD,STA/tSU,STOP maybe out of spec due to device
> clock-stretching or circuit loss, we could get device
> clock-stretch time from dts to adjust these parameters
> to meet the spec via EXT_CONF register.
>
> Signed-off-by: Qii Wang <[email protected]>
> ---
> drivers/i2c/busses/i2c-mt65xx.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index 2ffd2f3..47c7255 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -245,6 +245,7 @@ struct mtk_i2c {
> u16 irq_stat; /* interrupt status */
> unsigned int clk_src_div;
> unsigned int speed_hz; /* The speed in transfer */
> + unsigned int clock_stretch_ns;
> enum mtk_trans_op op;
> u16 timing_reg;
> u16 high_speed_reg;
> @@ -607,7 +608,8 @@ static int mtk_i2c_check_ac_timing(struct mtk_i2c *i2c,
> else
> clk_ns = sample_ns / 2;
>
> - su_sta_cnt = DIV_ROUND_UP(spec->min_su_sta_ns, clk_ns);
> + su_sta_cnt = DIV_ROUND_UP(spec->min_su_sta_ns + i2c->clock_stretch_ns,
> + clk_ns);
> if (su_sta_cnt > max_sta_cnt)
> return -1;
>
> @@ -1171,6 +1173,8 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
> if (i2c->clk_src_div == 0)
> return -EINVAL;
>
> + of_property_read_u32(np, "clock-stretch-ns", &i2c->clock_stretch_ns);
> +

I think this new property "clock-stretch-ns" is for the same purpose of
"i2c-scl-falling-time-ns" + "i2c-scl-rising-time-ns" defined in
Documentation/devicetree/bindings/i2c/i2c.txt?

> i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
> i2c->use_push_pull =
> of_property_read_bool(np, "mediatek,use-push-pull");
> --
> 1.9.1
> _______________________________________________
> Linux-mediatek mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-mediatek

2021-03-04 06:22:47

by Qii Wang (王琪)

Subject: Re: [PATCH] i2c: mediatek: Get device clock-stretch time via dts

Hi,
On Tue, 2021-03-02 at 19:30 +0800, Ikjoon Jang wrote:
> Hi Qii,
> >
> > @@ -1171,6 +1173,8 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
> > if (i2c->clk_src_div == 0)
> > return -EINVAL;
> >
> > + of_property_read_u32(np, "clock-stretch-ns", &i2c->clock_stretch_ns);
> > +
>
> I think this new property "clock-stretch-ns" is for the same purpose of
> "i2c-scl-falling-time-ns" + "i2c-scl-rising-time-ns" defined in
> Documentation/devicetree/bindings/i2c/i2c.txt?
>

I haven't find the corresponding instructions;and this patch is for the
problem caused by clock-stretch when the scl is pulled.

> > i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
> > i2c->use_push_pull =
> > of_property_read_bool(np, "mediatek,use-push-pull");
> > --
> > 1.9.1
> > _______________________________________________
> > Linux-mediatek mailing list
> > [email protected]
> > http://lists.infradead.org/mailman/listinfo/linux-mediatek