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authorLaxman Dewangan <ldewangan@nvidia.com>2016-04-22 14:39:41 +0200
committerMark Brown <broonie@kernel.org>2016-04-22 17:26:41 +0200
commit5aa43599daddbe972f955b2357c76866a6f92973 (patch)
tree4aecd5266aeb3bbeaa41e7fdf257fd9b65e158fa /drivers/regulator/max77620-regulator.c
parentregulator: max77620: Add details of device specific ramp rate setting (diff)
downloadlinux-5aa43599daddbe972f955b2357c76866a6f92973.tar.xz
linux-5aa43599daddbe972f955b2357c76866a6f92973.zip
regulator: max77620: Add support for device specific ramp rate setting
Maxim advertised the ramp rate of the rail with some recommended design specification like output capacitance of rail should be 2.2uF. This make sure that current change in the rail is within maximum current limit and hence meet the advertised ramp rate. If there is variation in design which causes the rail current to change more that maximum current limit then device applies the current limit. In this case, ramp rate is different than advertised ramp rate. Add device specific settings for ramp rate which need to be configure on device register when measure ramp rate on platform is deviated from advertised ramp rate. In this case, all delay time calculation for voltage change is done with measured ramp rate and device ramp rate is used for configuring the device register. If measured ramp rate in the platform is same as advertised ramp rate then regulator-ramp-delay is used for the device register configuration and ramp time calculation for voltage change. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/regulator/max77620-regulator.c')
-rw-r--r--drivers/regulator/max77620-regulator.c83
1 files changed, 56 insertions, 27 deletions
diff --git a/drivers/regulator/max77620-regulator.c b/drivers/regulator/max77620-regulator.c
index 73a3356a5c19..321e804aeab0 100644
--- a/drivers/regulator/max77620-regulator.c
+++ b/drivers/regulator/max77620-regulator.c
@@ -81,6 +81,7 @@ struct max77620_regulator_pdata {
int suspend_fps_pd_slot;
int suspend_fps_pu_slot;
int current_mode;
+ int ramp_rate_setting;
};
struct max77620_regulator {
@@ -307,6 +308,43 @@ static int max77620_read_slew_rate(struct max77620_regulator *pmic, int id)
return 0;
}
+static int max77620_set_slew_rate(struct max77620_regulator *pmic, int id,
+ int slew_rate)
+{
+ struct max77620_regulator_info *rinfo = pmic->rinfo[id];
+ unsigned int val;
+ int ret;
+ u8 mask;
+
+ if (rinfo->type == MAX77620_REGULATOR_TYPE_SD) {
+ if (slew_rate <= 13750)
+ val = 0;
+ else if (slew_rate <= 27500)
+ val = 1;
+ else if (slew_rate <= 55000)
+ val = 2;
+ else
+ val = 3;
+ val <<= MAX77620_SD_SR_SHIFT;
+ mask = MAX77620_SD_SR_MASK;
+ } else {
+ if (slew_rate <= 5000)
+ val = 1;
+ else
+ val = 0;
+ mask = MAX77620_LDO_SLEW_RATE_MASK;
+ }
+
+ ret = regmap_update_bits(pmic->rmap, rinfo->cfg_addr, mask, val);
+ if (ret < 0) {
+ dev_err(pmic->dev, "Regulator %d slew rate set failed: %d\n",
+ id, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
static int max77620_init_pmic(struct max77620_regulator *pmic, int id)
{
struct max77620_regulator_pdata *rpdata = &pmic->reg_pdata[id];
@@ -351,6 +389,13 @@ static int max77620_init_pmic(struct max77620_regulator *pmic, int id)
if (ret < 0)
return ret;
+ if (rpdata->ramp_rate_setting) {
+ ret = max77620_set_slew_rate(pmic, id,
+ rpdata->ramp_rate_setting);
+ if (ret < 0)
+ return ret;
+ }
+
return 0;
}
@@ -502,35 +547,16 @@ static int max77620_regulator_set_ramp_delay(struct regulator_dev *rdev,
{
struct max77620_regulator *pmic = rdev_get_drvdata(rdev);
int id = rdev_get_id(rdev);
- struct max77620_regulator_info *rinfo = pmic->rinfo[id];
- int ret, val;
- u8 mask;
-
- if (rinfo->type == MAX77620_REGULATOR_TYPE_SD) {
- if (ramp_delay <= 13750)
- val = 0;
- else if (ramp_delay <= 27500)
- val = 1;
- else if (ramp_delay <= 55000)
- val = 2;
- else
- val = 3;
- val <<= MAX77620_SD_SR_SHIFT;
- mask = MAX77620_SD_SR_MASK;
- } else {
- if (ramp_delay <= 5000)
- val = 1;
- else
- val = 0;
- mask = MAX77620_LDO_SLEW_RATE_MASK;
- }
+ struct max77620_regulator_pdata *rpdata = &pmic->reg_pdata[id];
- ret = regmap_update_bits(pmic->rmap, rinfo->cfg_addr, mask, val);
- if (ret < 0)
- dev_err(pmic->dev, "Reg 0x%02x update failed: %d\n",
- rinfo->cfg_addr, ret);
+ /* Device specific ramp rate setting tells that platform has
+ * different ramp rate from advertised value. In this case,
+ * do not configure anything and just return success.
+ */
+ if (rpdata->ramp_rate_setting)
+ return 0;
- return ret;
+ return max77620_set_slew_rate(pmic, id, ramp_delay);
}
static int max77620_of_parse_cb(struct device_node *np,
@@ -563,6 +589,9 @@ static int max77620_of_parse_cb(struct device_node *np,
np, "maxim,suspend-fps-power-down-slot", &pval);
rpdata->suspend_fps_pd_slot = (!ret) ? pval : -1;
+ ret = of_property_read_u32(np, "maxim,ramp-rate-setting", &pval);
+ rpdata->ramp_rate_setting = (!ret) ? pval : 0;
+
return max77620_init_pmic(pmic, desc->id);
}