[PATCH v4 13/15] power: axp20x_battery: Add constant charge current table

From: Aidan MacDonald
Date: Wed Jun 29 2022 - 10:30:57 EST


Add a table-based lookup method for constant charge current,
which is necessary when the setting cannot be represented as
a linear range.

This also replaces the hard-coded 300 mA default ccc setting
if the DT-specified value is unsupported; the minimum value
for the device is now set exactly instead of relying on the
value being rounded down to a supported value.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@xxxxxxxxx>
---
drivers/power/supply/axp20x_battery.c | 59 +++++++++++++++++++++------
1 file changed, 47 insertions(+), 12 deletions(-)

diff --git a/drivers/power/supply/axp20x_battery.c b/drivers/power/supply/axp20x_battery.c
index 9106077c0dbb..401779d84d2b 100644
--- a/drivers/power/supply/axp20x_battery.c
+++ b/drivers/power/supply/axp20x_battery.c
@@ -61,6 +61,14 @@ struct axp20x_batt_ps;
struct axp_data {
int ccc_scale;
int ccc_offset;
+ /*
+ * Lookup table for constant charge current, if provided this is used
+ * instead of ccc_scale/ccc_offset.
+ *
+ * The table is indexed by the field AXP20X_CHRG_CTRL1_TGT_CURR so it
+ * must have AXP20X_CHRG_CTRL1_TGT_CURR+1 elements.
+ */
+ const int *ccc_table;
bool has_fg_valid;
int (*get_max_voltage)(struct axp20x_batt_ps *batt, int *val);
int (*set_max_voltage)(struct axp20x_batt_ps *batt, int val);
@@ -176,7 +184,10 @@ static int axp20x_get_constant_charge_current(struct axp20x_batt_ps *axp,

*val &= AXP20X_CHRG_CTRL1_TGT_CURR;

- *val = *val * axp->data->ccc_scale + axp->data->ccc_offset;
+ if (axp->data->ccc_table)
+ *val = axp->data->ccc_table[*val];
+ else
+ *val = *val * axp->data->ccc_scale + axp->data->ccc_offset;

return 0;
}
@@ -389,16 +400,35 @@ static int axp20x_battery_set_max_voltage(struct axp20x_batt_ps *axp20x_batt,
AXP20X_CHRG_CTRL1_TGT_VOLT, val);
}

+static int axp20x_get_constant_charge_current_sel(struct axp20x_batt_ps *axp_batt,
+ int charge_current)
+{
+ int i;
+
+ if (axp_batt->data->ccc_table) {
+ for (i = AXP20X_CHRG_CTRL1_TGT_CURR; i >= 0; i--) {
+ if (axp_batt->data->ccc_table[i] <= charge_current)
+ return i;
+ }
+
+ return -EINVAL;
+ }
+
+ i = (charge_current - axp_batt->data->ccc_offset) / axp_batt->data->ccc_scale;
+ if (i > AXP20X_CHRG_CTRL1_TGT_CURR || i < 0)
+ return -EINVAL;
+
+ return i;
+}
+
static int axp20x_set_constant_charge_current(struct axp20x_batt_ps *axp_batt,
int charge_current)
{
if (charge_current > axp_batt->max_ccc)
return -EINVAL;

- charge_current = (charge_current - axp_batt->data->ccc_offset) /
- axp_batt->data->ccc_scale;
-
- if (charge_current > AXP20X_CHRG_CTRL1_TGT_CURR || charge_current < 0)
+ charge_current = axp20x_get_constant_charge_current_sel(axp_batt, charge_current);
+ if (charge_current < 0)
return -EINVAL;

return regmap_update_bits(axp_batt->regmap, AXP20X_CHRG_CTRL1,
@@ -410,14 +440,14 @@ static int axp20x_set_max_constant_charge_current(struct axp20x_batt_ps *axp,
{
bool lower_max = false;

- charge_current = (charge_current - axp->data->ccc_offset) /
- axp->data->ccc_scale;
-
- if (charge_current > AXP20X_CHRG_CTRL1_TGT_CURR || charge_current < 0)
+ charge_current = axp20x_get_constant_charge_current_sel(axp, charge_current);
+ if (charge_current < 0)
return -EINVAL;

- charge_current = charge_current * axp->data->ccc_scale +
- axp->data->ccc_offset;
+ if (axp->data->ccc_table)
+ charge_current = axp->data->ccc_table[charge_current];
+ else
+ charge_current = charge_current * axp->data->ccc_scale + axp->data->ccc_offset;

if (charge_current > axp->max_ccc)
dev_warn(axp->dev,
@@ -629,7 +659,12 @@ static int axp20x_power_probe(struct platform_device *pdev)
ccc)) {
dev_err(&pdev->dev,
"couldn't set constant charge current from DT: fallback to minimum value\n");
- ccc = 300000;
+
+ if (axp20x_batt->data->ccc_table)
+ ccc = axp20x_batt->data->ccc_table[0];
+ else
+ ccc = axp20x_batt->data->ccc_offset;
+
axp20x_batt->max_ccc = ccc;
axp20x_set_constant_charge_current(axp20x_batt, ccc);
}
--
2.35.1