From c32885c71bed47239a7c6113e1c0a83171bee04e Mon Sep 17 00:00:00 2001 From: Sumit Semwal Date: Thu, 28 May 2020 12:30:15 +0530 Subject: regulator: Allow regulators to verify enabled during enable() Some regulators might need to verify that they have indeed been enabled after the enable() call is made and enable_time delay has passed. This is implemented by repeatedly checking is_enabled() upto poll_enabled_time, waiting for the already calculated enable delay in each iteration. Signed-off-by: Sumit Semwal Change-Id: I8f0c9f6aaa1be5373628b1bcd77dbd6a53c65d0e --- v3: addressed minor review comments, improved kernel doc v2: Address review comments, including swapping enable_time and poll_enabled_time. --- drivers/regulator/core.c | 63 +++++++++++++++++++++++++++++++++++++++- include/linux/regulator/driver.h | 5 ++++ 2 files changed, 67 insertions(+), 1 deletion(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 03154f5b939f..538a2779986a 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -2347,6 +2347,37 @@ static void _regulator_enable_delay(unsigned int delay) udelay(us); } +/** + * _regulator_check_status_enabled + * + * A helper function to check if the regulator status can be interpreted + * as 'regulator is enabled'. + * @rdev: the regulator device to check + * + * Return: + * * 1 - if status shows regulator is in enabled state + * * 0 - if not enabled state + * * Error Value - as received from ops->get_status() + */ +static inline int _regulator_check_status_enabled(struct regulator_dev *rdev) +{ + int ret = rdev->desc->ops->get_status(rdev); + + if (ret < 0) { + rdev_info(rdev, "get_status returned error: %d\n", ret); + return ret; + } + + switch (ret) { + case REGULATOR_STATUS_OFF: + case REGULATOR_STATUS_ERROR: + case REGULATOR_STATUS_UNDEFINED: + return 0; + default: + return 1; + } +} + static int _regulator_do_enable(struct regulator_dev *rdev) { int ret, delay; @@ -2407,7 +2438,37 @@ static int _regulator_do_enable(struct regulator_dev *rdev) * together. */ trace_regulator_enable_delay(rdev_get_name(rdev)); - _regulator_enable_delay(delay); + /* If poll_enabled_time is set, poll upto the delay calculated + * above, delaying poll_enabled_time uS to check if the regulator + * actually got enabled. + * If the regulator isn't enabled after enable_delay has + * expired, return -ETIMEDOUT. + */ + if (rdev->desc->poll_enabled_time) { + unsigned int time_remaining = delay; + + while (time_remaining > 0) { + _regulator_enable_delay(rdev->desc->poll_enabled_time); + + if (rdev->desc->ops->get_status) { + ret = _regulator_check_status_enabled(rdev); + if (ret < 0) + return ret; + else if (ret) + break; + } else if (rdev->desc->ops->is_enabled(rdev)) + break; + + time_remaining -= rdev->desc->poll_enabled_time; + } + + if (time_remaining <= 0) { + rdev_err(rdev, "Enabled check timed out\n"); + return -ETIMEDOUT; + } + } else { + _regulator_enable_delay(delay); + } trace_regulator_enable_complete(rdev_get_name(rdev)); diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h index 7eb9fea8e482..436df3ba0b2a 100644 --- a/include/linux/regulator/driver.h +++ b/include/linux/regulator/driver.h @@ -305,6 +305,9 @@ enum regulator_type { * @enable_time: Time taken for initial enable of regulator (in uS). * @off_on_delay: guard time (in uS), before re-enabling a regulator * + * @poll_enabled_time: The polling interval (in uS) to use while checking that + * the regulator was actually enabled. Max upto enable_time. + * * @of_map_mode: Maps a hardware mode defined in a DeviceTree to a standard mode */ struct regulator_desc { @@ -372,6 +375,8 @@ struct regulator_desc { unsigned int off_on_delay; + unsigned int poll_enabled_time; + unsigned int (*of_map_mode)(unsigned int mode); }; -- cgit v1.2.3