From 61d7fdc49f03f4ec990974d1d2a8b05e64afeae4 Mon Sep 17 00:00:00 2001
From: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Date: Wed, 19 Jun 2019 11:56:36 -0700
Subject: [PATCH] regulator: qcom_spmi: Fix math of spmi_regulator_set_voltage_time_sel
Git-commit: 61d7fdc49f03f4ec990974d1d2a8b05e64afeae4
Patch-mainline: v5.3-rc1
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/regulator/qcom_spmi-regulator.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
--- a/drivers/regulator/qcom_spmi-regulator.c
+++ b/drivers/regulator/qcom_spmi-regulator.c
@@ -754,18 +754,17 @@ spmi_regulator_common_set_voltage(struct
return spmi_vreg_write(vreg, SPMI_COMMON_REG_VOLTAGE_RANGE, buf, 2);
}
+static int spmi_regulator_common_list_voltage(struct regulator_dev *rdev,
+ unsigned selector);
+
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);
}