Subject: [linux-sunxi] Re: [PATCH v3 4/4] power: Add an axp20x-usb-power driver

From: [email-masked] (Hans de Goede)
Date: Mon, 6 Jul 2015 14:20:22 +0200

Hi,

On 06-07-15 12:40, Maxime Ripard wrote:
> Hi,
>
> On Fri, Jun 26, 2015 at 12:59:17PM +0200, Hans de Goede wrote:
>> This adds a driver for the usb power_supply bits of the axp20x PMICs.
>>
>> I initially started writing my own driver, before coming aware of
>> Bruno Pr?mont's excellent earlier RFC with a driver for this.
>>
>> My driver was lacking CURRENT_MAX and VOLTAGE_MIN support Bruno's
>> drvier has, so I've copied the code for those from his driver.
>>
>> Note that the AC-power-supply and battery charger bits will need separate
>> drivers. Each one needs its own devictree child-node so that other
>> devicetree nodes can reference the right power-supply, and thus each one
>> will get its own mfd-cell / platform_device and platform-driver.
>>
>> Cc: Bruno Pr?mont <[email-masked]>
>> Acked-by: Lee Jones <[email-masked]>
>> Signed-off-by: Bruno Pr?mont <[email-masked]>
>> Signed-off-by: Hans de Goede <[email-masked]>
>> ---
>> Changes in v2:
>> -Split out the dt-bindings documentation into a separate patch
>> -Renamed axp20x_read_16bit to axp20x_read_variable_width
>> -Use better local variable names inside axp20x_read_variable_width
>> Changes in v3:
>> -Add Bruno's S-o-b
>> ---
>>   drivers/power/Kconfig            |   7 ++
>>   drivers/power/Makefile           |   1 +
>>   drivers/power/axp20x_usb_power.c | 243 +++++++++++++++++++++++++++++++++++++++
>>   include/linux/mfd/axp20x.h       |  24 ++++
>>   4 files changed, 275 insertions(+)
>>   create mode 100644 drivers/power/axp20x_usb_power.c
>>
>> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
>> index 4091fb0..1fee60c 100644
>> --- a/drivers/power/Kconfig
>> +++ b/drivers/power/Kconfig
>> @@ -439,6 +439,13 @@ config BATTERY_RT5033
>>   	  The fuelgauge calculates and determines the battery state of charge
>>   	  according to battery open circuit voltage.
>>
>> +config AXP20X_POWER
>> +	tristate "AXP20x power supply driver"
>> +	depends on MFD_AXP20X
>> +	help
>> +	  This driver provides support for the power supply features of
>> +	  AXP20x PMIC.
>> +
>>   source "drivers/power/reset/Kconfig"
>>
>>   endif # POWER_SUPPLY
>> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
>> index b7b0181..ae0f27d 100644
>> --- a/drivers/power/Makefile
>> +++ b/drivers/power/Makefile
>> @@ -9,6 +9,7 @@ obj-$(CONFIG_GENERIC_ADC_BATTERY)	+= generic-adc-battery.o
>>
>>   obj-$(CONFIG_PDA_POWER)		+= pda_power.o
>>   obj-$(CONFIG_APM_POWER)		+= apm_power.o
>> +obj-$(CONFIG_AXP20X_POWER)	+= axp20x_usb_power.o
>>   obj-$(CONFIG_MAX8925_POWER)	+= max8925_power.o
>>   obj-$(CONFIG_WM831X_BACKUP)	+= wm831x_backup.o
>>   obj-$(CONFIG_WM831X_POWER)	+= wm831x_power.o
>> diff --git a/drivers/power/axp20x_usb_power.c b/drivers/power/axp20x_usb_power.c
>> new file mode 100644
>> index 0000000..09f388e
>> --- /dev/null
>> +++ b/drivers/power/axp20x_usb_power.c
>> @@ -0,0 +1,243 @@
>> +/*
>> + * AXP20x PMIC USB power supply status driver
>> + *
>> + * Copyright (C) 2015 Hans de Goede <[email-masked]>
>> + * Copyright (C) 2014 Bruno Pr?mont <[email-masked]>
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under  the terms of the GNU General  Public License as published by the
>> + * Free Software Foundation;  either version 2 of the License, or (at your
>> + * option) any later version.
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/init.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/mfd/axp20x.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/power_supply.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +
>> +#define DRVNAME "axp20x-usb-power-supply"
>> +
>> +#define AXP20X_PWR_STATUS_VBUS_PRESENT	BIT(5)
>> +#define AXP20X_PWR_STATUS_VBUS_USED	BIT(4)
>> +
>> +#define AXP20X_USB_STATUS_VBUS_VALID	BIT(2)
>> +
>> +#define AXP20X_VBUS_VHOLD_uV(b)		(4000000 + (((b) >> 3) & 7) * 100000)
>> +#define AXP20X_VBUS_CLIMIT_MASK		3
>> +#define AXP20X_VBUC_CLIMIT_900mA	0
>> +#define AXP20X_VBUC_CLIMIT_500mA	1
>> +#define AXP20X_VBUC_CLIMIT_100mA	2
>> +#define AXP20X_VBUC_CLIMIT_NONE		3
>> +
>> +#define AXP20X_ADC_EN1_VBUS_CURR	BIT(2)
>> +#define AXP20X_ADC_EN1_VBUS_VOLT	BIT(3)
>> +
>> +#define AXP20X_VBUS_MON_VBUS_VALID	BIT(3)
>> +
>> +struct axp20x_usb_power {
>> +	struct regmap *regmap;
>> +	struct power_supply *supply;
>> +};
>> +
>> +static irqreturn_t axp20x_usb_power_irq(int irq, void *devid)
>> +{
>> +	struct axp20x_usb_power *power = devid;
>> +
>> +	power_supply_changed(power->supply);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int axp20x_usb_power_get_property(struct power_supply *psy,
>> +	enum power_supply_property psp, union power_supply_propval *val)
>> +{
>> +	struct axp20x_usb_power *power = power_supply_get_drvdata(psy);
>> +	unsigned int input, v;
>> +	int r;
>> +
>> +	switch (psp) {
>> +	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
>> +		r = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
>> +		if (r)
>> +			return r;
>> +
>> +		val->intval = AXP20X_VBUS_VHOLD_uV(v);
>> +		return 0;
>> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
>> +		r = axp20x_read_variable_width(power->regmap,
>> +					       AXP20X_VBUS_V_ADC_H, 12);
>> +		if (r < 0)
>> +			return r;
>> +
>> +		val->intval = r * 1700; /* 1 step = 1.7 mV */
>
> Eventually, as we will have more users (the various power supplies,
> the TS pin?), we should have an IIO driver for the internal ADC.

IMHO an IIO driver is only useful in case the TS or gpio pins are
used in ADC mode, and sofar we've not encountered any boards using that,

In my expereince the IIO framework is overly complicated and usually gets
in the way more then it helps.

> Do you know how close it is from the AXP288's ?

No I've not compared the 2.

>> +		return 0;
>> +	case POWER_SUPPLY_PROP_CURRENT_MAX:
>> +		r = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
>> +		if (r)
>> +			return r;
>> +
>> +		switch (v & AXP20X_VBUS_CLIMIT_MASK) {
>> +		case AXP20X_VBUC_CLIMIT_100mA:
>> +			val->intval = 100000;
>> +			break;
>> +		case AXP20X_VBUC_CLIMIT_500mA:
>> +			val->intval = 500000;
>> +			break;
>> +		case AXP20X_VBUC_CLIMIT_900mA:
>> +			val->intval = 900000;
>> +			break;
>> +		case AXP20X_VBUC_CLIMIT_NONE:
>> +			val->intval = -1;
>> +			break;
>> +		}
>> +		return 0;
>> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
>> +		r = axp20x_read_variable_width(power->regmap,
>> +					       AXP20X_VBUS_I_ADC_H, 12);
>> +		if (r < 0)
>> +			return r;
>> +
>> +		val->intval = r * 375; /* 1 step = 0.375 mA */
>
> And here too.
>
>> +		return 0;
>> +	default:
>> +		break;
>> +	}
>> +
>> +	/* All the properties below need the input-status reg value */
>> +	r = regmap_read(power->regmap, AXP20X_PWR_INPUT_STATUS, &input);
>> +	if (r)
>> +		return r;
>> +
>> +	switch (psp) {
>> +	case POWER_SUPPLY_PROP_HEALTH:
>> +		if (!(input & AXP20X_PWR_STATUS_VBUS_PRESENT)) {
>> +			val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
>> +			break;
>> +		}
>> +
>> +		r = regmap_read(power->regmap, AXP20X_USB_OTG_STATUS, &v);
>> +		if (r)
>> +			return r;
>> +
>> +		if (!(v & AXP20X_USB_STATUS_VBUS_VALID)) {
>> +			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
>> +			break;
>> +		}
>> +
>> +		val->intval = POWER_SUPPLY_HEALTH_GOOD;
>> +		break;
>> +	case POWER_SUPPLY_PROP_PRESENT:
>> +		val->intval = !!(input & AXP20X_PWR_STATUS_VBUS_PRESENT);
>> +		break;
>> +	case POWER_SUPPLY_PROP_ONLINE:
>> +		val->intval = !!(input & AXP20X_PWR_STATUS_VBUS_USED);
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static enum power_supply_property axp20x_usb_power_properties[] = {
>> +	POWER_SUPPLY_PROP_HEALTH,
>> +	POWER_SUPPLY_PROP_PRESENT,
>> +	POWER_SUPPLY_PROP_ONLINE,
>> +	POWER_SUPPLY_PROP_VOLTAGE_MIN,
>> +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
>> +	POWER_SUPPLY_PROP_CURRENT_MAX,
>> +	POWER_SUPPLY_PROP_CURRENT_NOW,
>> +};
>> +
>> +static const struct power_supply_desc axp20x_usb_power_desc = {
>> +	.name = "axp20x-usb",
>> +	.type = POWER_SUPPLY_TYPE_USB,
>> +	.properties = axp20x_usb_power_properties,
>> +	.num_properties = ARRAY_SIZE(axp20x_usb_power_properties),
>> +	.get_property = axp20x_usb_power_get_property,
>> +};
>> +
>> +static int axp20x_usb_power_probe(struct platform_device *pdev)
>> +{
>> +	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
>> +	struct power_supply_config psy_cfg = {};
>> +	struct axp20x_usb_power *power;
>> +	static const char * const irq_names[] = { "VBUS_PLUGIN",
>> +		"VBUS_REMOVAL", "VBUS_VALID", "VBUS_NOT_VALID" };
>> +	int i, irq, r;
>> +
>> +	if (!of_device_is_available(pdev->dev.of_node))
>> +		return -ENODEV;
>
> That looks odd. Is it even going to be probed in the first place?

Yes, the mfd framework will instantiate all cells listed for an mfd
device without checking there are compatible child-nodes present
in the dtb.

>> +
>> +	power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
>> +	if (!power)
>> +		return -ENOMEM;
>> +
>> +	power->regmap = axp20x->regmap;
>
> It should probably be wise to test that the axp20x pointer is not
> NULL.

The platform device we are probing has been instantiated by the mfd
framework after setting the parent device driver ptr, so this will never
be not NULL.

>> +
>> +	/* Enable vbus valid checking */
>> +	r = regmap_update_bits(power->regmap, AXP20X_VBUS_MON,
>> +		    AXP20X_VBUS_MON_VBUS_VALID, AXP20X_VBUS_MON_VBUS_VALID);
>> +	if (r)
>> +		return r;
>> +
>> +	/* Enable vbus voltage and current measurement */
>> +	r = regmap_update_bits(power->regmap, AXP20X_ADC_EN1,
>> +			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT,
>> +			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT);
>> +	if (r)
>> +		return r;
>> +
>> +	psy_cfg.of_node = pdev->dev.of_node;
>> +	psy_cfg.drv_data = power;
>> +
>> +	power->supply = devm_power_supply_register(&pdev->dev,
>> +					&axp20x_usb_power_desc, &psy_cfg);
>> +	if (IS_ERR(power->supply))
>> +		return PTR_ERR(power->supply);
>> +
>> +	/* Request irqs after registering, as irqs may trigger immediately */
>> +	for (i = 0; i < ARRAY_SIZE(irq_names); i++) {
>> +		irq = platform_get_irq_byname(pdev, irq_names[i]);
>> +		if (irq < 0) {
>> +			dev_warn(&pdev->dev, "No IRQ for %s: %d\n",
>> +				 irq_names[i], irq);
>> +			continue;
>> +		}
>> +		irq = regmap_irq_get_virq(axp20x->regmap_irqc, irq);
>> +		r = devm_request_any_context_irq(&pdev->dev, irq,
>> +				axp20x_usb_power_irq, 0, DRVNAME, power);
>> +		if (r < 0)
>> +			dev_warn(&pdev->dev, "Error requesting %s IRQ: %d\n",
>> +				 irq_names[i], r);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id axp20x_usb_power_match[] = {
>> +	{ .compatible = "x-powers,axp202-usb-power-supply" },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, axp20x_usb_power_match);
>> +
>> +static struct platform_driver axp20x_usb_power_driver = {
>> +	.probe = axp20x_usb_power_probe,
>> +	.driver = {
>> +		.name = DRVNAME,
>> +		.of_match_table = axp20x_usb_power_match,
>> +	},
>> +};
>> +
>> +module_platform_driver(axp20x_usb_power_driver);
>> +
>> +MODULE_AUTHOR("Hans de Goede <[email-masked]>");
>> +MODULE_DESCRIPTION("AXP20x PMIC USB power supply status driver");
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
>> index 6d8b39a..8ec996e 100644
>> --- a/include/linux/mfd/axp20x.h
>> +++ b/include/linux/mfd/axp20x.h
>> @@ -11,6 +11,8 @@
>>   #ifndef __LINUX_MFD_AXP20X_H
>>   #define __LINUX_MFD_AXP20X_H
>>
>> +#include <linux/regmap.h>
>> +
>>   enum {
>>   	AXP202_ID = 0,
>>   	AXP209_ID,
>> @@ -372,4 +374,26 @@ struct axp288_extcon_pdata {
>>   	struct gpio_desc *gpio_mux_cntl;
>>   };
>>
>> +/* generic helper function for reading 9-16 bit wide regs */
>> +static inline int axp20x_read_variable_width(struct regmap *regmap,
>> +	unsigned int reg, unsigned int width)
>> +{
>> +	unsigned int reg_val, result;
>> +	int err;
>> +
>> +	err = regmap_read(regmap, reg, &reg_val);
>> +	if (err)
>> +		return err;
>> +
>> +	result = reg_val << (width - 8);
>> +
>> +	err = regmap_read(regmap, reg + 1, &reg_val);
>> +	if (err)
>> +		return err;
>> +
>> +	result |= reg_val;
>> +
>> +	return result;
>> +}
>> +
>>   #endif /* __LINUX_MFD_AXP20X_H */
>> --
>> 2.4.3

Regards,

Hans