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Message-ID: <554A360C.7020401@intel.com>
Date: Wed, 06 May 2015 18:41:00 +0300
From: Anda-Maria Nicolae <anda-maria.nicolae@...el.com>
To: Laurentiu Palcu <laurentiu.palcu@...el.com>
CC: sre@...nel.org, dbaryshkov@...il.com, robh+dt@...nel.org,
pawel.moll@....com, mark.rutland@....com,
ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
dwmw2@...radead.org, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v3] power_supply: Add support for Richtek rt9455 battery
charger
Hi Laurentiu,
Inline are the answers to your comments.
Thanks,
Anda
On 05/06/2015 02:40 PM, Laurentiu Palcu wrote:
> On Tue, May 05, 2015 at 07:32:10PM +0300, Anda-Maria Nicolae wrote:
>> Based on the datasheet found here:
>> http://www.richtek.com/download_ds.jsp?p=RT9455
>>
>> Signed-off-by: Anda-Maria Nicolae <anda-maria.nicolae@...el.com>
>> ---
>>
>> Updates from v2 version:
>> - removed unused masks and keep the used ones. I have tried to access mask field
>> from struct regmap_field, but I have received the following compilation error:
>> "dereferencing pointer to incomplete type". I think this happens because I include
>> the file include/linux/regmap.h and in this file struct regmap_field is only declared
>> and not defined. Struct regmap_field is defined in drivers/base/regmap/internal.h.
>> If I include this file, compilation works. But I do not think it is a good idea
>> to include it; I did not find any other driver which includes this file. I also
>> could not find any driver that accesses mask field from struct regmap_field.
> If you want to go this path, which looks promising since you can get rid
> of all mask macros, you don't need regmap_field to compute your masks.
> You need reg_field (include/linux/regmap.h). When you setup your fields,
> you use:
>
> static const struct reg_field rt9455_reg_fields[] = {...};
>
> Hence, you have access to both msb and lsb of each field and you can
> easily compute your mask. Just an idea.
>
Because the masks are constant, I believe it is better to define macros
for them instead of calculating every time the driver uses one of them.
This is why I wanted to use mask field: to avoid calculating them and to
remove the macros.
>> For instance, drivers/pwm/pwm-sti.c at lines 157, 158, also uses masks.
>>
>> - I have also kept REG_FIELD definitions for interrupt registers, since, for instance,
>> I use F_BATAB to check battery presence property.
>>
>> - cached regs 0x05 and 0x06. Also, I have added rt9455_is_writeable_reg function
>> for writeable_reg field of regmap_config.
>>
>> - used POWER_STATUS_DISCHARGING, replaced break with and replaced it with return and
>> indented it correctly. I spent some time on this and I finally understood what is happening.
>> So, if PWR_RDY bit is set, but STAT bits value is 0, the charger may be in one
>> of the following cases:
>> 1. CHG_EN bit is 0.
>> 2. CHG_EN bit is 1 but the battery is not connected.
>> In any of these cases, POWER_SUPPLY_STATUS_NOT_CHARGING is returned.
>> If the PWR_RDY bit is cleared, POWER_SUPPLY_STATUS_DISCHARGING is returned.
>>
>> - used VOREG bits value instead of VMREG in functions rt9455_charger_get_voltage_max()/
>> rt9455_charger_set_voltage_max(). Although RT9455 charger has VMREG bits which,
>> according to the datasheet, represent "Maximum battery regulation voltage", the
>> charger never uses VMREG value as maximum threshold for battery voltage. This
>> happens because TE and TE_SHDN_EN bits are set during rt9455_probe(), and charging
>> operation is terminated when charging current is less than ICHRG x IEOC. When charging
>> operation is terminated, battery voltage is almost equal to VOREG. Therefore,
>> VMREG value is not taken into account. This is the reason why VOREG value is
>> set/returned in these functions.
> Something's not right... What happens in the following scenario:
> VMREG=4.2V (default value) and user sets VOREG=4.45V? Did you test this
> case. I really doubt VMREG field is not used at all. Of course, you can set
> VMREG to maximum value in which case VMREG doesn't really matter.
I have set VMREG to its maximum value in rt9455_hw_init() function.
Please take a look at my last patch.
Yes, I have tested this case with a battery whose voltage is 3.97V,
VOREG = 4.45V and VMREG = 4.2V. The charger drains current from the
power source. If I set VOREG to 4V, from 4.45V, Charge done interrupt is
triggered and no current is drained from the power source. If I increase
VMREG to 4.45V, and keep VOREG to 4V, no input current is drained from
the power source, but if I increase VOREG to 4.2V, the charger drains
current from the power source. This is why I have decided to use VOREG
instead of VMREG.
>
>> - corrected comment from rt9455_usb_event_id() function.
>>
>> - replaced IS_ERR_OR_NULL() with IS_ERR() to check the result of usb_get_phy()
>> function. Also, if usb_register_notifier() fails, since usb_put_phy() is immediately
>> called, I have set info->usb_phy to ERR_PTR(-ENODEV) so that in rt9455_remove()
>> usb_put_phy is not mistakenly called again.
>>
>> .../devicetree/bindings/power/rt9455_charger.txt | 43 +
>> .../devicetree/bindings/vendor-prefixes.txt | 1 +
>> drivers/power/Kconfig | 6 +
>> drivers/power/Makefile | 1 +
>> drivers/power/rt9455_charger.c | 1801 ++++++++++++++++++++
>> 5 files changed, 1852 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/power/rt9455_charger.txt
>> create mode 100644 drivers/power/rt9455_charger.c
>>
> (...)
>
>> +static int rt9455_charger_get_status(struct rt9455_info *info,
>> + union power_supply_propval *val)
>> +{
>> + unsigned int v, pwr_rdy;
>> + int ret;
>> +
>> + ret = regmap_field_read(info->regmap_fields[F_STAT], &v);
>> + if (ret) {
>> + dev_err(&info->client->dev, "Failed to read STAT bits\n");
>> + return ret;
>> + }
>> +
>> + switch (v) {
>> + case 0:
>> + ret = regmap_field_read(info->regmap_fields[F_PWR_RDY],
>> + &pwr_rdy);
>> + if (ret) {
>> + dev_err(&info->client->dev, "Failed to read PWR_RDY bit\n");
>> + return ret;
>> + }
>> +
>> + if (!pwr_rdy) {
>> + val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
>> + return 0;
>> + }
>> + /*
>> + * If PWR_RDY bit is set, but STAT bits value is 0, the charger
>> + * may be in one of the following cases:
>> + * 1. CHG_EN bit is 0.
>> + * 2. CHG_EN bit is 1 but the battery is not connected.
>> + * In any of these cases, POWER_SUPPLY_STATUS_NOT_CHARGING is
>> + * returned.
>> + */
>> + val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
>> + return 0;
> If STAT is always 0 when charger is removed, I guess this solution is
> fine. Though you could do the PWR_RDY check first and, if it's 1, you
> could then continue with STAT evaluation.
>
>> + case 1:
>> + val->intval = POWER_SUPPLY_STATUS_CHARGING;
>> + return 0;
>> + case 2:
>> + val->intval = POWER_SUPPLY_STATUS_FULL;
>> + return 0;
>> + default:
>> + val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
>> + return 0;
>> + }
>> +}
>> +
> (...)
>> +
>> +static int rt9455_charger_get_voltage(struct rt9455_info *info,
>> + union power_supply_propval *val)
>> +{
>> + int voltage;
>> + int ret;
>> +
>> + ret = rt9455_get_field_val(info, F_VOREG,
>> + rt9455_voreg_values,
>> + ARRAY_SIZE(rt9455_voreg_values),
>> + &voltage);
>> + if (ret) {
>> + dev_err(&info->client->dev, "Failed to read VOREG value\n");
>> + return ret;
>> + }
>> +
>> + val->intval = voltage;
>> +
>> + return 0;
>> +}
>> +
>> +static int rt9455_charger_get_voltage_max(struct rt9455_info *info,
>> + union power_supply_propval *val)
>> +{
>> + /*
>> + * Although RT9455 charger has VMREG bits which, according to the
>> + * datasheet, represent "Maximum battery regulation voltage", the
>> + * charger never uses VMREG value as maximum threshold for battery
>> + * voltage. This happens because TE and TE_SHDN_EN bits are set during
>> + * rt9455_probe(), and charging operation is terminated when charging
>> + * current is less than ICHRG x IEOC. When charging operation is
>> + * terminated, battery voltage is almost equal to VOREG. Therefore,
>> + * VMREG value is not taken into account. This is the reason why maximum
>> + * VOREG value is returned in this function. Also, maximum VOREG value
>> + * equals maximum VMREG value: 4.45V.
>> + */
>> + int idx = ARRAY_SIZE(rt9455_voreg_values) - 1;
>> +
>> + val->intval = rt9455_voreg_values[idx];
>> +
>> + return 0;
>> +}
>> +
> (...)
>> +
>> +static int rt9455_charger_set_voltage(struct rt9455_info *info,
>> + const union power_supply_propval *val)
>> +{
>> + return rt9455_set_field_val(info, F_VOREG,
>> + rt9455_voreg_values,
>> + ARRAY_SIZE(rt9455_voreg_values),
>> + val->intval);
>> +}
>> +
>> +static int rt9455_charger_set_voltage_max(struct rt9455_info *info,
>> + const union power_supply_propval *val)
>> +{
>> + /*
>> + * Although RT9455 charger has VMREG bits which, according to the
>> + * datasheet, represent "Maximum battery regulation voltage", the
>> + * charger never uses VMREG value as maximum threshold for battery
>> + * voltage. This happens because TE and TE_SHDN_EN bits are set during
>> + * rt9455_probe(), and charging operation is terminated when charging
>> + * current is less than ICHRG x IEOC. When charging operation is
>> + * terminated, battery voltage is almost equal to VOREG. Therefore,
>> + * VMREG value is not taken into account. This is the reason why VOREG
>> + * value is set in this function.
>> + */
>> + return rt9455_set_field_val(info, F_VOREG,
>> + rt9455_voreg_values,
>> + ARRAY_SIZE(rt9455_voreg_values),
>> + val->intval);
>> +}
> Apparently, rt9455_charger_set_voltage_max() and
> rt9455_charger_set_voltage() do the same thing?
Yes, they do the same thing. If I increase VMREG instead of VOREG, the
charger does not drain current if the battery voltage is almost equal to
VOREG and I think the user wants the contrary.
> (...)
>
>> +static int rt9455_usb_event_id(struct rt9455_info *info,
>> + u8 opa_mode, u8 iaicr)
>> +{
>> + struct device *dev = &info->client->dev;
>> + int ret;
>> +
>> + if (opa_mode == RT9455_CHARGE_MODE) {
>> + /*
>> + * If the charger is in charge mode, and it has received
>> + * USB_EVENT_ID, this means a consumer device is connected and
>> + * it should be powered by the charger.
>> + * In this case, the charger goes into boost mode.
>> + */
>> + dev_dbg(dev, "USB_EVENT_ID received, therefore the charger goes into boost mode\n");
>> + ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
>> + RT9455_BOOST_MODE);
> I missed this previously but, when you switch to boost mode here,
> shouldn't you set the boost output voltage somewhere? According to
> chip's specification, VOREG is used for both battery regulation and
> boost output. So, if the user sets the battery regulation to 4.45
> (maximum), when switching to boost mode you'll end up with 5.6V on VBUS
> rail. I'm not an expert in USB specifications but a quick google search
> revealed that the maximum VBUS voltage is 5.25V.
>
> Perhaps you should add a DT property to let the user choose boost output
> voltage.
Did not know that. I understand. Will do it.
>> + if (ret) {
>> + dev_err(dev, "Failed to set charger in boost mode\n");
>> + return NOTIFY_DONE;
>> + }
>> + }
>> +
>> + dev_dbg(dev, "USB_EVENT_ID received, therefore IAICR is set to its minimum value\n");
>> + if (iaicr != RT9455_IAICR_100MA) {
>> + ret = regmap_field_write(info->regmap_fields[F_IAICR],
>> + RT9455_IAICR_100MA);
>> + if (ret) {
>> + dev_err(dev, "Failed to set IAICR value\n");
>> + return NOTIFY_DONE;
>> + }
>> + }
>> +
>> + return NOTIFY_OK;
>> +}
>> +
> (...)
>> +
>> +static int rt9455_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
>> + struct device *dev = &client->dev;
>> + struct rt9455_info *info;
>> + struct power_supply_config rt9455_charger_config = {};
>> + /* mandatory device-specific data values */
>> + u32 ichrg, ieoc_percentage, voreg;
>> + /* optional device-specific data values */
>> + u32 mivr = -1, iaicr = -1;
>> + int i, ret;
>> +
>> + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
>> + dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
>> + return -ENODEV;
>> + }
>> + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
>> + if (!info)
>> + return -ENOMEM;
>> +
>> + info->client = client;
>> + i2c_set_clientdata(client, info);
>> +
>> + info->regmap = devm_regmap_init_i2c(client,
>> + &rt9455_regmap_config);
>> + if (IS_ERR(info->regmap)) {
>> + dev_err(dev, "Failed to initialize register map\n");
>> + return -EINVAL;
>> + }
>> +
>> + for (i = 0; i < F_MAX_FIELDS; i++) {
>> + info->regmap_fields[i] =
>> + devm_regmap_field_alloc(dev, info->regmap,
>> + rt9455_reg_fields[i]);
>> + if (IS_ERR(info->regmap_fields[i])) {
>> + dev_err(dev,
>> + "Failed to allocate regmap field = %d\n", i);
>> + return PTR_ERR(info->regmap_fields[i]);
>> + }
>> + }
>> +
>> + ret = rt9455_discover_charger(info, &ichrg, &ieoc_percentage,
>> + &voreg, &mivr, &iaicr);
>> + if (ret) {
>> + dev_err(dev, "Failed to discover charger\n");
>> + return ret;
>> + }
>> +
>> +#if IS_ENABLED(CONFIG_USB_PHY)
>> + info->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
> If you used devm_usb_get_phy() you wouldn't have to worry about
> releasing usb_phy(as Krzysztof suggested in the previous mail). It's up
> to you.
>
Ok.
>> + if (IS_ERR(info->usb_phy)) {
>> + dev_err(dev, "Failed to get USB transceiver\n");
>> + } else {
>> + info->nb.notifier_call = rt9455_usb_event;
>> + ret = usb_register_notifier(info->usb_phy, &info->nb);
>> + if (ret) {
>> + dev_err(dev, "Failed to register USB notifier\n");
>> + usb_put_phy(info->usb_phy);
>> + /*
>> + * Since usb_put_phy() has been called, info->usb_phy is
>> + * set to ERR_PTR so that in rt9455_remove()
>> + * usb_put_phy() is not mistakenly called again.
>> + */
>> + info->usb_phy = ERR_PTR(-ENODEV);
>> + }
>> + }
>> +#endif
>> +
>> + INIT_DEFERRABLE_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
>> + INIT_DEFERRABLE_WORK(&info->max_charging_time_work,
>> + rt9455_max_charging_time_work_callback);
>> + INIT_DEFERRABLE_WORK(&info->batt_presence_work,
>> + rt9455_batt_presence_work_callback);
>> +
>> + rt9455_charger_config.of_node = dev->of_node;
>> + rt9455_charger_config.drv_data = info;
>> + rt9455_charger_config.supplied_to = rt9455_charger_supplied_to;
>> + rt9455_charger_config.num_supplicants =
>> + ARRAY_SIZE(rt9455_charger_supplied_to);
>> + ret = devm_request_threaded_irq(dev, client->irq, NULL,
>> + rt9455_irq_handler_thread,
>> + IRQF_TRIGGER_LOW | IRQF_ONESHOT,
>> + RT9455_DRIVER_NAME, info);
>> + if (ret) {
>> + dev_err(dev, "Failed to register IRQ handler\n");
>> + return ret;
>> + }
>> +
>> + ret = rt9455_hw_init(info, ichrg, ieoc_percentage, voreg, mivr, iaicr);
>> + if (ret) {
>> + dev_err(dev, "Failed to set charger to its default values\n");
>> + return ret;
>> + }
>> +
>> + info->charger = power_supply_register(dev, &rt9455_charger_desc,
>> + &rt9455_charger_config);
>> + if (IS_ERR(info->charger)) {
>> + dev_err(dev, "Failed to register charger\n");
>> + ret = PTR_ERR(info->charger);
>> + goto put_usb_phy;
>> + }
>> +
>> + return 0;
>> +
>> +put_usb_phy:
>> +#if IS_ENABLED(CONFIG_USB_PHY)
>> + if (!IS_ERR(info->usb_phy)) {
>> + usb_unregister_notifier(info->usb_phy, &info->nb);
>> + usb_put_phy(info->usb_phy);
>> + info->usb_phy = ERR_PTR(-ENODEV);
>> + }
>> +#endif
>> + return ret;
>> +}
>> +
>> +static int rt9455_remove(struct i2c_client *client)
>> +{
>> + int ret;
>> + struct rt9455_info *info = i2c_get_clientdata(client);
>> +
>> + ret = rt9455_register_reset(info);
>> + if (ret)
>> + dev_err(&info->client->dev, "Failed to set charger to its default values\n");
>> +
>> +#if IS_ENABLED(CONFIG_USB_PHY)
>> + if (!IS_ERR(info->usb_phy)) {
>> + usb_unregister_notifier(info->usb_phy, &info->nb);
>> + usb_put_phy(info->usb_phy);
>> + }
>> +#endif
>> +
>> + cancel_delayed_work_sync(&info->pwr_rdy_work);
>> + cancel_delayed_work_sync(&info->max_charging_time_work);
>> + cancel_delayed_work_sync(&info->batt_presence_work);
>> +
>> + power_supply_unregister(info->charger);
>> +
>> + return ret;
>> +}
>> +
>> +static const struct i2c_device_id rt9455_i2c_id_table[] = {
>> + { RT9455_DRIVER_NAME, 0 },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, rt9455_i2c_id_table);
>> +
>> +static const struct of_device_id rt9455_of_match[] = {
>> + { .compatible = "richtek,rt9455", },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, rt9455_of_match);
>> +
>> +static const struct acpi_device_id rt9455_i2c_acpi_match[] = {
>> + { "RT945500", 0 },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(acpi, rt9455_i2c_acpi_match);
>> +
>> +static struct i2c_driver rt9455_driver = {
>> + .probe = rt9455_probe,
>> + .remove = rt9455_remove,
>> + .id_table = rt9455_i2c_id_table,
>> + .driver = {
>> + .name = RT9455_DRIVER_NAME,
>> + .of_match_table = of_match_ptr(rt9455_of_match),
>> + .acpi_match_table = ACPI_PTR(rt9455_i2c_acpi_match),
>> + },
>> +};
>> +module_i2c_driver(rt9455_driver);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_AUTHOR("Anda-Maria Nicolae <anda-maria.nicolae@...el.com>");
>> +MODULE_ALIAS("i2c:rt9455-charger");
>> +MODULE_DESCRIPTION("Richtek RT9455 Charger Driver");
>> --
>> 1.7.9.5
>>
>> --
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