From: Konrad Dybcio Date: Tue, 6 Feb 2024 18:43:36 +0000 (+0100) Subject: clk: qcom: reset: Ensure write completion on reset de/assertion X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2f8cf2c3f3e3f7ef61bd19abb4b0bb797ad50aaf;p=linux.git clk: qcom: reset: Ensure write completion on reset de/assertion Trying to toggle the resets in a rapid fashion can lead to the changes not actually arriving at the clock controller block when we expect them to. This was observed at least on SM8250. Read back the value after regmap_update_bits to ensure write completion. Fixes: b36ba30c8ac6 ("clk: qcom: Add reset controller support") Signed-off-by: Konrad Dybcio Link: https://lore.kernel.org/r/20240105-topic-venus_reset-v2-3-c37eba13b5ce@linaro.org Signed-off-by: Bjorn Andersson --- diff --git a/drivers/clk/qcom/reset.c b/drivers/clk/qcom/reset.c index 20d1d35aaf229..d96c96a9089f4 100644 --- a/drivers/clk/qcom/reset.c +++ b/drivers/clk/qcom/reset.c @@ -33,7 +33,12 @@ static int qcom_reset_set_assert(struct reset_controller_dev *rcdev, map = &rst->reset_map[id]; mask = map->bitmask ? map->bitmask : BIT(map->bit); - return regmap_update_bits(rst->regmap, map->reg, mask, assert ? mask : 0); + regmap_update_bits(rst->regmap, map->reg, mask, assert ? mask : 0); + + /* Read back the register to ensure write completion, ignore the value */ + regmap_read(rst->regmap, map->reg, &mask); + + return 0; } static int qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)