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>

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index bf25acb..5ddfa4e 100644 (file)
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -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;
 }