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clk: qcom: reset: Allow specifying custom reset delay

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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@kernkonzept.com
This commit is contained in:
Stephan Gerhold 2022-07-06 15:41:29 +02:00 committed by Bjorn Andersson
parent bf37a05744
commit 2cb8a39b67
2 changed files with 4 additions and 1 deletions
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4
drivers/clk/qcom/reset.c
View File

@ -13,8 +13,10 @@
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;
}

1
drivers/clk/qcom/reset.h
View File

@ -11,6 +11,7 @@
struct qcom_reset_map {
unsigned int reg;
u8 bit;
u8 udelay;
};
struct regmap;