Re: [PATCH] [RFC]power: battery: Generic battery driver using IIO

From: Lars-Peter Clausen
Date: Tue Sep 11 2012 - 05:59:15 EST


On 09/10/2012 05:40 PM, anish kumar wrote:
> From: anish kumar <anish198519851985@xxxxxxxxx>
>
> This is the cleaned up code after the valuable inputs from
> the Jonathan, Lars and Anton.
>
> I have tried to accomodate all the concerns however please
> let me know incase something is missed out.
>
> Signed-off-by: anish kumar <anish198519851985@xxxxxxxxx>

Hi,


> ---
> drivers/power/generic-adc-battery.c | 431 +++++++++++++++++++++++++++++
> include/linux/power/generic-adc-battery.h | 33 +++
> 2 files changed, 464 insertions(+), 0 deletions(-)
> create mode 100644 drivers/power/generic-adc-battery.c
> create mode 100644 include/linux/power/generic-adc-battery.h
>
> diff --git a/drivers/power/generic-adc-battery.c b/drivers/power/generic-adc-battery.c
> new file mode 100644
> index 0000000..3459740
> --- /dev/null
> +++ b/drivers/power/generic-adc-battery.c
> @@ -0,0 +1,431 @@
[...]
> +
> +static int generic_adc_bat_get_property(struct power_supply *psy,
> + enum power_supply_property psp,
> + union power_supply_propval *val)
> +{
> + struct generic_adc_bat *adc_bat;
> + int scaleint, scalepart, iio_val, ret = 0;
> + long result = 0;
> +
> + adc_bat = to_generic_bat(psy);
> + if (!adc_bat) {
> + dev_err(psy->dev, "no battery infos ?!\n");
> + return -EINVAL;
> + }
> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_POWER_NOW:
> + ret = iio_read_channel_raw(adc_bat->channel[POWER],
> + &iio_val);
> + ret = iio_read_channel_scale(adc_bat->channel[POWER],
> + &scaleint, &scalepart);
> + if (ret < 0)
> + return ret;
> + break;
> + case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> + ret = iio_read_channel_raw(adc_bat->channel[VOLTAGE],
> + &iio_val);
> + ret = iio_read_channel_scale(adc_bat->channel[VOLTAGE],
> + &scaleint, &scalepart);
> + if (ret < 0)
> + return ret;
> + break;
> + case POWER_SUPPLY_PROP_CURRENT_NOW:
> + ret = iio_read_channel_raw(adc_bat->channel[CURRENT],
> + &iio_val);
> + ret = iio_read_channel_scale(adc_bat->channel[CURRENT],
> + &scaleint, &scalepart);
> + if (ret < 0)
> + return ret;
> + break;
> + default:
> + break;
> + }
> +
> + switch (ret) {
> + case IIO_VAL_INT:
> + result = iio_val * scaleint;
> + break;
> + case IIO_VAL_INT_PLUS_MICRO:
> + result = (s64)iio_val * (s64)scaleint +
> + div_s64((s64)iio_val * (s64)scalepart, 1000000LL);
> + break;
> + case IIO_VAL_INT_PLUS_NANO:
> + result = (s64)iio_val * (s64)scaleint +
> + div_s64((s64)iio_val * (s64)scalepart, 1000000000LL);
> + break;
> + }

I think it's a good idea to factor the channel reading and scale conversion
out into a helper function.

> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_STATUS:
> + if (adc_bat->pdata.gpio_charge_finished < 0)

gpio_is_valid

> + val->intval = adc_bat->level == 100000 ?
> + POWER_SUPPLY_STATUS_FULL : adc_bat->status;
> + else
> + val->intval = adc_bat->status;
> + break;
[...]
> + return ret;
> +}
> +

[...]

> +static void generic_adc_bat_work(struct work_struct *work)
> +{
> + struct generic_adc_bat *adc_bat;
> + struct delayed_work *delayed_work;
> + int is_charged;
> + int is_plugged;
> +
> + delayed_work = container_of(work,
> + struct delayed_work, work);
> + adc_bat = container_of(delayed_work,
> + struct generic_adc_bat, bat_work);
> +
> + /* backup battery doesn't have current monitoring capability anyway */
> + is_plugged = power_supply_am_i_supplied(&adc_bat->psy);
> + adc_bat->cable_plugged = is_plugged;
> + if (is_plugged != adc_bat->was_plugged) {
> + adc_bat->was_plugged = is_plugged;
> + if (is_plugged)
> + adc_bat->status = POWER_SUPPLY_STATUS_CHARGING;
> + else
> + adc_bat->status = POWER_SUPPLY_STATUS_DISCHARGING;
> + } else {
> + if ((adc_bat->pdata.gpio_charge_finished >= 0) && is_plugged) {

gpio_is_valid

> + is_charged = charge_finished(adc_bat);
> + if (is_charged)
> + adc_bat->status = POWER_SUPPLY_STATUS_FULL;
> + else
> + adc_bat->status = POWER_SUPPLY_STATUS_CHARGING;
> + }
> + }
> +
> + power_supply_changed(&adc_bat->psy);
> +}

[...]

> +
> +/*
> + * compare the pdata->channel names with the predefined channels and
> + * returns the index of the channel in channel_name array or -1 in the
> + * case of not-found.
> + */
> +int channel_cmp(char *name)
> +{
> + if (!strcmp(name, channel_name[VOLTAGE]))
> + return VOLTAGE;
> + else if (!strcmp(name, channel_name[CURRENT]))
> + return CURRENT;
> + else if (!strcmp(name, channel_name[POWER]))
> + return POWER;
> + else
> + return -1;
> +}
> +
> +static int __devinit generic_adc_bat_probe(struct platform_device *pdev)
> +{
> + struct iio_battery_platform_data *pdata = pdev->dev.platform_data;
> + int ret, chan_index;
> +
> + /* copying the battery name from platform data */
> + adc_bat.psy.name = pdata->battery_name;

You should make a per device copy of adc_bat, otherwise there can only be
one device at a time.

> +
> + /* bootup default values for the battery */
> + adc_bat.volt_value = -1;
> + adc_bat.cur_value = -1;
> + adc_bat.cable_plugged = 0;
> + adc_bat.status = POWER_SUPPLY_STATUS_DISCHARGING;
> +
> + /* calculate the total number of channels */
> + for (chan_index = 0; pdata->channel_name[chan_index]; chan_index++)
> + ;
> +
> + if (!chan_index) {
> + pr_err("atleast provide one channel\n");
> + return -EINVAL;
> + }
> +
> + /* copying the static properties and allocating extra memory for holding
> + * the extra configurable properties received from platform data.
> + */
> + adc_bat.psy.properties = kzalloc(sizeof(bat_props)
> + + sizeof(int)*chan_index, GFP_KERNEL);
> + if (!adc_bat.psy.properties) {
> + ret = -ENOMEM;
> + goto first_mem_fail;
> + }
> + memcpy(adc_bat.psy.properties, bat_props, sizeof(bat_props));
> +
> + /* allocating memory for iio channels */
> + adc_bat.channel = kzalloc(chan_index * sizeof(struct iio_channel),
> + GFP_KERNEL);
> + if (!adc_bat.channel) {
> + ret = -ENOMEM;
> + goto second_mem_fail;
> + }
> +
> + /*
> + * getting channel from iio and copying the battery properties
> + * based on the channel set in the platform data.
> + */
> + for (chan_index = 0; pdata->channel_name[chan_index]; chan_index++) {
> + int channel = channel_cmp(pdata->channel_name[chan_index]);
> + if (channel < 0) {
> + ret = -EINVAL;
> + goto second_mem_fail;
> + }
> +
> + adc_bat.channel[chan_index] =
> + iio_channel_get(dev_name(&pdev->dev),
> + pdata->channel_name[chan_index]);

Just request the channel with the hardcoded channel names. There is no need
to pass these in via platform data. If a channel is not found just skip it
and continue with the next one. Only if 0 channels were found return an error.

> + if (IS_ERR(adc_bat.channel[chan_index])) {
> + ret = PTR_ERR(adc_bat.channel[chan_index]);
> + goto second_mem_fail;
> + }
> +
> + memcpy(adc_bat.psy.properties+sizeof(bat_props),
> + &dyn_props[channel], sizeof(dyn_props[channel]));

You need to increase the offset for each new property.

> + }
> +
> + ret = power_supply_register(&pdev->dev, &adc_bat.psy);
> + if (ret)
> + goto err_reg_fail;
> +
> + INIT_DELAYED_WORK(&adc_bat.bat_work, generic_adc_bat_work);
> +
> + if (gpio_is_valid(pdata->gpio_charge_finished)) {
> + ret = gpio_request(pdata->gpio_charge_finished, "charged");
> + if (ret)
> + goto err_gpio;
> +
> + ret = request_irq(gpio_to_irq(pdata->gpio_charge_finished),
> + generic_adc_bat_charged,
> + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> + "battery charged", &adc_bat);

I'd make this request_any_context_irq, some IRQ expander use nested IRQs.

> + if (ret)
> + goto err_gpio;
> + } else
> + goto err_gpio; /* let's bail out */
> +
> + platform_set_drvdata(pdev, &adc_bat);
> + /* Schedule timer to check current status */
> + schedule_delayed_work(&adc_bat.bat_work,
> + msecs_to_jiffies(0));
> + return 0;
> +
> +err_gpio:
> + power_supply_unregister(&adc_bat.psy);
> +err_reg_fail:
> + for (chan_index = 0; pdata->channel_name[chan_index]; chan_index++)
> + iio_channel_release(adc_bat.channel[chan_index]);
> + kfree(adc_bat.channel);
> +second_mem_fail:
> + kfree(adc_bat.psy.properties);
> +first_mem_fail:
> + return ret;
> +}
> +
> +static int generic_adc_bat_remove(struct platform_device *pdev)
> +{
> + int chan_index;
> + struct iio_battery_platform_data *pdata = pdev->dev.platform_data;
> + struct generic_adc_bat *adc_bat = to_generic_bat(pdata);
> +
> + power_supply_unregister(&adc_bat->psy);
> +
> + if (pdata->gpio_charge_finished >= 0) {

gpio_is_valid

> + free_irq(gpio_to_irq(pdata->gpio_charge_finished), NULL);
> + gpio_free(pdata->gpio_charge_finished);
> + }
> +
> + for (chan_index = 0; pdata->channel_name[chan_index]; chan_index++)
> + iio_channel_release(adc_bat->channel[chan_index]);
> + cancel_delayed_work(&adc_bat->bat_work);
> + return 0;
> +}

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