From: Stephan Gerhold stephan.gerhold@kernkonzept.com
[ Upstream commit 2cb8a39b6781ea23accd1fa93b3ad000d0948aec ]
The amount of time required between asserting and deasserting the reset signal can vary depending on the involved hardware component. Sometimes 1 us might not be enough and a larger delay is necessary to conform to the specifications.
Usually this is worked around in the consuming drivers, by replacing reset_control_reset() with a sequence of reset_control_assert(), waiting for a custom delay, followed by reset_control_deassert().
However, in some cases the driver making use of the reset is generic and can be used with different reset controllers. In this case the reset time requirement is better handled directly by the reset controller driver.
Make this possible by adding an "udelay" field to the qcom_reset_map that allows setting a different reset delay (in microseconds).
Signed-off-by: Stephan Gerhold stephan.gerhold@kernkonzept.com Signed-off-by: Bjorn Andersson andersson@kernel.org Link: https://lore.kernel.org/r/20220706134132.3623415-4-stephan.gerhold@kernkonze... Stable-dep-of: 2f8cf2c3f3e3 ("clk: qcom: reset: Ensure write completion on reset de/assertion") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/qcom/reset.c | 4 +++- drivers/clk/qcom/reset.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/qcom/reset.c b/drivers/clk/qcom/reset.c index 0324d8daab9bc..fc68c8fa30ac7 100644 --- a/drivers/clk/qcom/reset.c +++ b/drivers/clk/qcom/reset.c @@ -21,8 +21,10 @@
static int qcom_reset(struct reset_controller_dev *rcdev, unsigned long id) { + struct qcom_reset_controller *rst = to_qcom_reset_controller(rcdev); + rcdev->ops->assert(rcdev, id); - udelay(1); + udelay(rst->reset_map[id].udelay ?: 1); /* use 1 us as default */ rcdev->ops->deassert(rcdev, id); return 0; } diff --git a/drivers/clk/qcom/reset.h b/drivers/clk/qcom/reset.h index cda877927d43a..3e30f6724c7a4 100644 --- a/drivers/clk/qcom/reset.h +++ b/drivers/clk/qcom/reset.h @@ -19,6 +19,7 @@ struct qcom_reset_map { unsigned int reg; u8 bit; + u8 udelay; };
struct regmap;