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authorJeffrey Hugo <jeffrey.l.hugo@gmail.com>2019-06-19 11:56:36 -0700
committerMark Brown <broonie@kernel.org>2019-06-20 14:18:57 +0100
commit61d7fdc49f03f4ec990974d1d2a8b05e64afeae4 (patch)
tree3ece87bf6c4d89a4323ec0c28067b1be6ccd852d /drivers/regulator
parentfd5d10059d5ead12dd12f05ae6d96e70d1fac3df (diff)
downloadlinux-61d7fdc49f03f4ec990974d1d2a8b05e64afeae4.tar.bz2
regulator: qcom_spmi: Fix math of spmi_regulator_set_voltage_time_sel
spmi_regulator_set_voltage_time_sel() calculates the amount of delay needed as the result of setting a new voltage. Essentially this is the absolute difference of the old and new voltages, divided by the slew rate. The implementation of spmi_regulator_set_voltage_time_sel() is wrong. It attempts to calculate the difference in voltages by using the difference in selectors and multiplying by the voltage step between selectors. This ignores the possibility that the old and new selectors might be from different ranges, which have different step values. Also, the difference between the selectors may encapsulate N ranges inbetween, so a summation of each selector change from old to new would be needed. Lets avoid all of that complexity, and just get the actual voltage represented by both the old and new selector, and use those to directly compute the voltage delta. This is more straight forward, and has the side benifit of avoiding issues with regulator implementations that don't have hardware register support to get the current configured range. Fixes: e92a4047419c ("regulator: Add QCOM SPMI regulator driver") Reported-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reported-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> Reported-by: Mark Brown <broonie@kernel.org> Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Tested-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/regulator')
-rw-r--r--drivers/regulator/qcom_spmi-regulator.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/regulator/qcom_spmi-regulator.c b/drivers/regulator/qcom_spmi-regulator.c
index 13f83be50076..877df33e0246 100644
--- a/drivers/regulator/qcom_spmi-regulator.c
+++ b/drivers/regulator/qcom_spmi-regulator.c
@@ -813,14 +813,10 @@ static int spmi_regulator_set_voltage_time_sel(struct regulator_dev *rdev,
unsigned int old_selector, unsigned int new_selector)
{
struct spmi_regulator *vreg = rdev_get_drvdata(rdev);
- const struct spmi_voltage_range *range;
int diff_uV;
- range = spmi_regulator_find_range(vreg);
- if (!range)
- return -EINVAL;
-
- diff_uV = abs(new_selector - old_selector) * range->step_uV;
+ diff_uV = abs(spmi_regulator_common_list_voltage(rdev, new_selector) -
+ spmi_regulator_common_list_voltage(rdev, old_selector));
return DIV_ROUND_UP(diff_uV, vreg->slew_rate);
}