Re: [PATCH] power: supply: max77759_charger: fix voltage scale (mV -> uV)
From: Sebastian Reichel
Date: Thu Apr 02 2026 - 18:29:09 EST
Hi,
On Thu, Apr 02, 2026 at 07:15:29AM +0000, Amit Sunil Dhamne via B4 Relay wrote:
> From: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
>
> CONSTANT_CHARGE_VOLTAGE_MAX property incorrectly uses mV instead of uV.
> Add fix to use uV as per the power-supply subsystem convention.
>
> Also, add a note indicating all the properties use non negative values.
> A negative value indicates failure with the appropriate error value. In
> that case, it should not be taken as a measurement value or status.
>
> Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
> ---
> This patch is a follow-up to the series [1]. [1] has been accepted in
> the USB subsystem tree (usb-next). However, since Sebastian has additional
> feedback [2], I am sending this patch to address it. Please note that this
> patch is based out of usb-next branch on usb tree. This patch should be
> applied on top of 70d7dd27f6dc ("power: supply: max77759: add charger driver").
>
> [1] https://lore.kernel.org/all/20260325-max77759-charger-v9-0-4486dd297adc@xxxxxxxxxx/
> [2] https://lore.kernel.org/all/ac2jYUA2F5oQsA2g@venus/#t
> ---
Fixes: 70d7dd27f6dc ("power: supply: max77759: add charger driver")
Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Greetings,
-- Sebastian
> Output of power supply selftest:
> root@google-gs:/data/power_supply# ./test_power_supply_properties.sh
> TAP version 13
> 1..66
> # Testing device max77759-charger
> ok 1 max77759-charger.exists
> ok 2 max77759-charger.uevent.NAME
> ok 3 max77759-charger.sysfs.type
> ok 4 max77759-charger.uevent.TYPE
> ok 5 max77759-charger.sysfs.usb_type # SKIP
> # Reported: '1' ()
> ok 6 max77759-charger.sysfs.online
> # Reported: '1' ()
> ok 7 max77759-charger.sysfs.present
> # Reported: 'Charging'
> ok 8 max77759-charger.sysfs.status
> ok 9 max77759-charger.sysfs.capacity # SKIP
> ok 10 max77759-charger.sysfs.capacity_level # SKIP
> ok 11 max77759-charger.sysfs.model_name # SKIP
> ok 12 max77759-charger.sysfs.manufacturer # SKIP
> ok 13 max77759-charger.sysfs.serial_number # SKIP
> ok 14 max77759-charger.sysfs.technology # SKIP
> ok 15 max77759-charger.sysfs.cycle_count # SKIP
> ok 16 max77759-charger.sysfs.scope # SKIP
> # Reported: '3000000' uA (3000 mA)
> ok 17 max77759-charger.sysfs.input_current_limit
> ok 18 max77759-charger.sysfs.input_voltage_limit # SKIP
> ok 19 max77759-charger.sysfs.voltage_now # SKIP
> ok 20 max77759-charger.sysfs.voltage_min # SKIP
> ok 21 max77759-charger.sysfs.voltage_max # SKIP
> ok 22 max77759-charger.sysfs.voltage_min_design # SKIP
> ok 23 max77759-charger.sysfs.voltage_max_design # SKIP
> ok 24 max77759-charger.sysfs.current_now # SKIP
> ok 25 max77759-charger.sysfs.current_max # SKIP
> ok 26 max77759-charger.sysfs.charge_now # SKIP
> ok 27 max77759-charger.sysfs.charge_full # SKIP
> ok 28 max77759-charger.sysfs.charge_full_design # SKIP
> ok 29 max77759-charger.sysfs.power_now # SKIP
> ok 30 max77759-charger.sysfs.energy_now # SKIP
> ok 31 max77759-charger.sysfs.energy_full # SKIP
> ok 32 max77759-charger.sysfs.energy_full_design # SKIP
> ok 33 max77759-charger.sysfs.energy_full_design # SKIP
> # Testing device tcpm-source-psy-1-0025
> ok 34 tcpm-source-psy-1-0025.exists
> ok 35 tcpm-source-psy-1-0025.uevent.NAME
> ok 36 tcpm-source-psy-1-0025.sysfs.type
> ok 37 tcpm-source-psy-1-0025.uevent.TYPE
> # Reported: 'C [PD] PD_PPS PD_SPR_AVS PD_PPS_SPR_AVS' ()
> ok 38 tcpm-source-psy-1-0025.sysfs.usb_type
> # Reported: '1' ()
> ok 39 tcpm-source-psy-1-0025.sysfs.online
> ok 40 tcpm-source-psy-1-0025.sysfs.present # SKIP
> ok 41 tcpm-source-psy-1-0025.sysfs.status # SKIP
> ok 42 tcpm-source-psy-1-0025.sysfs.capacity # SKIP
> ok 43 tcpm-source-psy-1-0025.sysfs.capacity_level # SKIP
> ok 44 tcpm-source-psy-1-0025.sysfs.model_name # SKIP
> ok 45 tcpm-source-psy-1-0025.sysfs.manufacturer # SKIP
> ok 46 tcpm-source-psy-1-0025.sysfs.serial_number # SKIP
> ok 47 tcpm-source-psy-1-0025.sysfs.technology # SKIP
> ok 48 tcpm-source-psy-1-0025.sysfs.cycle_count # SKIP
> ok 49 tcpm-source-psy-1-0025.sysfs.scope # SKIP
> ok 50 tcpm-source-psy-1-0025.sysfs.input_current_limit # SKIP
> ok 51 tcpm-source-psy-1-0025.sysfs.input_voltage_limit # SKIP
> # Reported: '5000000' uV (5 V)
> ok 52 tcpm-source-psy-1-0025.sysfs.voltage_now
> # Reported: '5000000' uV (5 V)
> ok 53 tcpm-source-psy-1-0025.sysfs.voltage_min
> # Reported: '5000000' uV (5 V)
> ok 54 tcpm-source-psy-1-0025.sysfs.voltage_max
> ok 55 tcpm-source-psy-1-0025.sysfs.voltage_min_design # SKIP
> ok 56 tcpm-source-psy-1-0025.sysfs.voltage_max_design # SKIP
> # Reported: '3000000' uA (3000 mA)
> ok 57 tcpm-source-psy-1-0025.sysfs.current_now
> # Reported: '3000000' uA (3000 mA)
> ok 58 tcpm-source-psy-1-0025.sysfs.current_max
> ok 59 tcpm-source-psy-1-0025.sysfs.charge_now # SKIP
> ok 60 tcpm-source-psy-1-0025.sysfs.charge_full # SKIP
> ok 61 tcpm-source-psy-1-0025.sysfs.charge_full_design # SKIP
> ok 62 tcpm-source-psy-1-0025.sysfs.power_now # SKIP
> ok 63 tcpm-source-psy-1-0025.sysfs.energy_now # SKIP
> ok 64 tcpm-source-psy-1-0025.sysfs.energy_full # SKIP
> ok 65 tcpm-source-psy-1-0025.sysfs.energy_full_design # SKIP
> ok 66 tcpm-source-psy-1-0025.sysfs.energy_full_design # SKIP
> # 47 skipped test(s) detected. Consider enabling relevant config options to improve coverage.
> # Totals: pass:19 fail:0 xfail:0 xpass:0 skip:47 error:0
> ---
> drivers/power/supply/max77759_charger.c | 21 +++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/power/supply/max77759_charger.c b/drivers/power/supply/max77759_charger.c
> index 9bb414599f16..58594bb78426 100644
> --- a/drivers/power/supply/max77759_charger.c
> +++ b/drivers/power/supply/max77759_charger.c
> @@ -26,7 +26,7 @@
>
> /* Default values for Fast Charge Current & Float Voltage */
> #define CHG_CC_DEFAULT_UA 2266770
> -#define CHG_FV_DEFAULT_MV 4300
> +#define CHG_FV_DEFAULT_UV 4300000
>
> #define MAX_NUM_RETRIES 3
> #define PSY_WORK_RETRY_DELAY_MS 10
> @@ -61,10 +61,10 @@ static const struct linear_range chgcc_limit_ranges[] = {
> LINEAR_RANGE(200000, 0x3, 0x3C, 66670),
> };
>
> -/* Charge Termination Voltage Limits (in mV) */
> +/* Charge Termination Voltage Limits (in uV) */
> static const struct linear_range chg_cv_prm_ranges[] = {
> - LINEAR_RANGE(3800, 0x38, 0x39, 100),
> - LINEAR_RANGE(4000, 0x0, 0x32, 10),
> + LINEAR_RANGE(3800000, 0x38, 0x39, 100000),
> + LINEAR_RANGE(4000000, 0x0, 0x32, 10000),
> };
>
> /* USB input current limits (in uA) */
> @@ -310,14 +310,14 @@ static int get_float_voltage(struct max77759_charger *chg)
> return ret ? ret : val;
> }
>
> -static int set_float_voltage_limit(struct max77759_charger *chg, u32 fv_mv)
> +static int set_float_voltage_limit(struct max77759_charger *chg, u32 fv_uv)
> {
> u32 regval;
> bool found;
>
> linear_range_get_selector_high_array(chg_cv_prm_ranges,
> ARRAY_SIZE(chg_cv_prm_ranges),
> - fv_mv, ®val, &found);
> + fv_uv, ®val, &found);
> if (!found)
> return -EINVAL;
>
> @@ -370,6 +370,11 @@ static const enum power_supply_property max77759_charger_props[] = {
> POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
> };
>
> +/*
> + * Note: None of the properties in this driver support usage of negative values.
> + * If you do see one, it's because the function is reporting an error value and
> + * should not be taken as a measurement value or status.
> + */
> static int max77759_charger_get_property(struct power_supply *psy,
> enum power_supply_property psp,
> union power_supply_propval *pval)
> @@ -557,10 +562,10 @@ static int max77759_charger_init(struct max77759_charger *chg)
> return ret;
>
> if (power_supply_get_battery_info(chg->psy, &info)) {
> - fv = CHG_FV_DEFAULT_MV;
> + fv = CHG_FV_DEFAULT_UV;
> fast_chg_curr = CHG_CC_DEFAULT_UA;
> } else {
> - fv = info->constant_charge_voltage_max_uv / 1000;
> + fv = info->constant_charge_voltage_max_uv;
> fast_chg_curr = info->constant_charge_current_max_ua;
> }
>
>
> ---
> base-commit: 81ebd43cc0d6d106ce7b6ccbf7b5e40ca7f5503d
> change-id: 20260402-fix-psy-max77759-usb-next-15a4f86a08ce
>
> Best regards,
> --
> Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
>
>
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