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Message-ID: <20180926135150.fla2r4ilfco3atws@earth.universe>
Date: Wed, 26 Sep 2018 15:51:50 +0200
From: Sebastian Reichel <sre@...nel.org>
To: Baolin Wang <baolin.wang@...aro.org>
Cc: robh+dt@...nel.org, mark.rutland@....com, linux-pm@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
yuanjiang.yu@...soc.com, broonie@...nel.org, ctatlor97@...il.com,
linus.walleij@...aro.org
Subject: Re: [PATCH v2 2/4] power: supply: core: Introduce properties to
present the battery OCV table
Hi,
On Wed, Sep 26, 2018 at 10:59:12AM +0800, Baolin Wang wrote:
> Some battery driver will use the open circuit voltage (OCV) value to look
> up the corresponding battery capacity percent in one certain degree Celsius.
> Thus this patch provides some battery properties to present the OCV table
> temperatures and OCV capacity table values.
>
> Suggested-by: Sebastian Reichel <sre@...nel.org>
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> ---
> Changes from v1:
> - New patch in v2.
> ---
> .../devicetree/bindings/power/supply/battery.txt | 14 +++++
> drivers/power/supply/power_supply_core.c | 63 +++++++++++++++++++-
> include/linux/power_supply.h | 11 ++++
> 3 files changed, 87 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt
> index 25b9d2e..ac2b303 100644
> --- a/Documentation/devicetree/bindings/power/supply/battery.txt
> +++ b/Documentation/devicetree/bindings/power/supply/battery.txt
> @@ -23,6 +23,16 @@ Optional Properties:
> - constant-charge-current-max-microamp: maximum constant input current
> - constant-charge-voltage-max-microvolt: maximum constant input voltage
> - internal-resistance-micro-ohms: battery internal resistance
> + - ocv-capacity-table-0: An array providing the battery capacity percent
> + with corresponding open circuit voltage (OCV) of the battery, which
> + is used to look up battery capacity according to current OCV value.
> + - ocv-capacity-table-1: Same as ocv-capacity-table-0
> + ......
> + - ocv-capacity-table-n: Same as ocv-capacity-table-0
> + - ocv-capacity-table-temperatures: An array containing the temperature
> + in degree Celsius, for each of the battery capacity lookup table.
> + The first temperature value specifies the OCV table 0, and the second
> + temperature value specifies the OCV table 1, and so on.
>
> Battery properties are named, where possible, for the corresponding
> elements in enum power_supply_property, defined in
> @@ -44,6 +54,10 @@ Example:
> constant-charge-current-max-microamp = <900000>;
> constant-charge-voltage-max-microvolt = <4200000>;
> internal-resistance-micro-ohms = <250000>;
> + ocv-capacity-table-temperatures = <(-10) 0 10>;
> + ocv-capacity-table-0 = <4185000 100>, <4113000 95>, <4066000 90>, ...;
> + ocv-capacity-table-1 = <4200000 100>, <4185000 95>, <4113000 90>, ...;
> + ocv-capacity-table-2 = <4250000 100>, <4200000 95>, <4185000 90>, ...;
> };
>
> charger: charger@11 {
> diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
> index 9f3452f..151ff03 100644
> --- a/drivers/power/supply/power_supply_core.c
> +++ b/drivers/power/supply/power_supply_core.c
> @@ -570,7 +570,7 @@ int power_supply_get_battery_info(struct power_supply *psy,
> {
> struct device_node *battery_np;
> const char *value;
> - int err;
> + int err, len, index;
>
> info->energy_full_design_uwh = -EINVAL;
> info->charge_full_design_uah = -EINVAL;
> @@ -581,6 +581,12 @@ int power_supply_get_battery_info(struct power_supply *psy,
> info->constant_charge_voltage_max_uv = -EINVAL;
> info->internal_resistance_uohm = -EINVAL;
>
> + for (index = 0; index < POWER_SUPPLY_OCV_TEMP_MAX; index++) {
> + info->ocv_table[index] = NULL;
> + info->ocv_temp[index] = -EINVAL;
> + info->ocv_table_size[index] = -EINVAL;
> + }
> +
> if (!psy->of_node) {
> dev_warn(&psy->dev, "%s currently only supports devicetree\n",
> __func__);
> @@ -620,10 +626,65 @@ int power_supply_get_battery_info(struct power_supply *psy,
> of_property_read_u32(battery_np, "internal-resistance-micro-ohms",
> &info->internal_resistance_uohm);
>
> + len = of_property_count_u32_elems(battery_np,
> + "ocv-capacity-table-temperatures");
> + if (len < 0 && len != -EINVAL) {
> + return len;
> + } else if (len > POWER_SUPPLY_OCV_TEMP_MAX) {
> + dev_err(&psy->dev, "Too many temperature values\n");
> + return -EINVAL;
> + } else if (len > 0) {
> + of_property_read_u32_array(battery_np,
> + "ocv-capacity-table-temperatures",
> + info->ocv_temp, len);
> + }
> +
> + for (index = 0; index < len; index++) {
> + struct power_supply_battery_ocv_table *table;
> + char *propname;
> + const __be32 *list;
> + int i, tab_len, size;
> +
> + propname = kasprintf(GFP_KERNEL, "ocv-capacity-table-%d", index);
> + list = of_get_property(battery_np, propname, &size);
> + kfree(propname);
> + if (!list || !size) {
> + dev_err(&psy->dev, "failed to get ocv capacity table\n");
I think it's better to replace "ocv capacity table" with %s / propname.
> + power_supply_put_battery_info(psy, info);
> + return -EINVAL;
> + }
> +
> + tab_len = size / sizeof(*table);
I think this should be
tab_len = size / (2 * sizeof(__be32));
which decouples DT memory layout from kernel memory layout.
> + info->ocv_table_size[index] = tab_len;
> +
> + table = info->ocv_table[index] = devm_kzalloc(&psy->dev,
> + tab_len * sizeof(*table),
> + GFP_KERNEL);
> + if (!info->ocv_table[index]) {
> + power_supply_put_battery_info(psy, info);
> + return -ENOMEM;
> + }
> +
> + for (i = 0; i < tab_len; i++) {
> + table[i].ocv = be32_to_cpu(*list++);
> + table[i].capacity = be32_to_cpu(*list++);
> + }
> + }
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(power_supply_get_battery_info);
>
> +void power_supply_put_battery_info(struct power_supply *psy,
> + struct power_supply_battery_info *info)
> +{
> + int i;
> +
> + for (i = 0; i < POWER_SUPPLY_OCV_TEMP_MAX; i++)
> + kfree(info->ocv_table[i]);
> +}
> +EXPORT_SYMBOL_GPL(power_supply_put_battery_info);
> +
> int power_supply_get_property(struct power_supply *psy,
> enum power_supply_property psp,
> union power_supply_propval *val)
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index 019452d..b0a2768 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -309,6 +309,12 @@ struct power_supply_info {
> int use_for_apm;
> };
>
> +struct power_supply_battery_ocv_table {
> + int ocv; /* microVolts */
> + int capacity; /* percent */
> +};
> +
> +#define POWER_SUPPLY_OCV_TEMP_MAX 20
> /*
> * This is the recommended struct to manage static battery parameters,
> * populated by power_supply_get_battery_info(). Most platform drivers should
> @@ -327,6 +333,9 @@ struct power_supply_battery_info {
> int constant_charge_current_max_ua; /* microAmps */
> int constant_charge_voltage_max_uv; /* microVolts */
> int internal_resistance_uohm; /* microOhms */
> + int ocv_temp[POWER_SUPPLY_OCV_TEMP_MAX]; /* celsius */
> + struct power_supply_battery_ocv_table *ocv_table[POWER_SUPPLY_OCV_TEMP_MAX];
> + int ocv_table_size[POWER_SUPPLY_OCV_TEMP_MAX];
> };
>
> extern struct atomic_notifier_head power_supply_notifier;
> @@ -350,6 +359,8 @@ extern struct power_supply *devm_power_supply_get_by_phandle(
>
> extern int power_supply_get_battery_info(struct power_supply *psy,
> struct power_supply_battery_info *info);
> +extern void power_supply_put_battery_info(struct power_supply *psy,
> + struct power_supply_battery_info *info);
> extern void power_supply_changed(struct power_supply *psy);
> extern int power_supply_am_i_supplied(struct power_supply *psy);
> extern int power_supply_set_input_current_limit_from_supplier(
Looks good to me. Technically this can result in existing users of
power_supply_get_battery_info leaking memory, if they have an OCV
table in DT.
-- Sebastian
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