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

[Krzysztof Kozlowski <k.kozlowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

W dniu 28.06.2015 o 05:25, Bruno Prémont pisze:
> On Sat, 27 Jun 2015 14:28:40 Krzysztof Kozlowski wrote:
>> W dniu 26.06.2015 o 19:59, Hans de Goede pisze:
>>> 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 Prémont'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 Prémont <bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org>
>>> Acked-by: Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>> Signed-off-by: Bruno Prémont <bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org>
>>> Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>> ---
>>> 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
>>
>> Hi,
>>
>> Two minor comments below, the driver itself looks good.
>>
>>
>>> ---
>>>  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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>> + * Copyright (C) 2014 Bruno Prémont <bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org>
>>> + *
>>> + * 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;
>>
>> Here and in probe function - it is strictly personal but I don't like
>> the 'r' variable. I got used to 'err' or 'ret' which are more
>> descriptive to me. 'r' may look like 'resource' for example.
> 
> 'ret' might work but doesn't it imply return value for this function
> instead of return value from a called function?

A little, but in this case it is indeed a return value from called
function. 'err' would fine as well.

> 
>>> +
>>> +	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 */
>>> +		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 */
>>> +		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;
>>> +
>>> +	power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
>>> +	if (!power)
>>> +		return -ENOMEM;
>>> +
>>> +	power->regmap = axp20x->regmap;
>>> +
>>> +	/* 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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>");
>>> +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 */
>>
>> Is this static inline function used outside of
>> drivers/power/axp20x_usb_power.c? Looks like it isn't, but maybe you
>> have a plan for it? If not, then it shouldn't be in header file.
> 
> See comments for first iteration of this patch:
> | | This is only used twice and only in one file.
> | |
> | | Do you know of any other uses of this call that will be upstreamed
> | | shortly?  
> | 
> | Yes I plan to write drivers for the other 3 power_supply class
> | cells (ac-power, battery-charger, rtc-bat-charger) in the axp209,
> | and most of those need the same helper which I why I put it here.  

Thanks for explanation.

Best regards,
Krzysztof

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