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i2c: mediatek: Use scl_int_delay_ns to compensate clock-stretching 

The parameters of tSU,STA/tHD,STA/tSU,STOP maybe out of spec due
to device clock-stretch or circuit loss, we could get a suitable
scl_int_delay_ns from i2c_timings to compensate these parameters
to meet the spec via EXT_CONF register.

Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Qii Wang 2021-04-17 14:46:52 +08:00 committed by Wolfram Sang
parent 3186b88044
commit a80f24945f
1 changed files with 5 additions and 1 deletions
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6
drivers/i2c/busses/i2c-mt65xx.c
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@ -231,6 +231,7 @@ struct mtk_i2c {
struct i2c_adapter adap; /* i2c host adapter */
struct device *dev;
struct completion msg_complete;
struct i2c_timings timing_info;
/* set in i2c probe */
void __iomem *base; /* i2c base addr */
@ -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->timing_info.scl_int_delay_ns, clk_ns);
if (su_sta_cnt > max_sta_cnt)
return -1;
@ -1176,6 +1178,8 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
i2c->use_push_pull =
of_property_read_bool(np, "mediatek,use-push-pull");
i2c_parse_fw_timings(i2c->dev, &i2c->timing_info, true);
return 0;
}