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

qii.wang
2021-03-13T08:06:43Z

From: Qii Wang <qii.wang@mediatek.com>

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 <qii.wang@mediatek.com>
---
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