Re: [PATCH 1/4] power: Add an axp20x-ac-power driver

Maxime Ripard
2016-04-04T21:38:51Z

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Hi,

On Sun, Apr 03, 2016 at 03:15:04PM +0200, Michael Haas wrote:
> This adds a driver for the ac power_supply bits of the axp20x
> PMICs.
>
> This submission is taken directly from Bruno Prémonts 2015 RFC [0].
> The original RFC contains drivers for AC, battery and backup
> battery. This commit only adds the AC driver for now.
>
> My only change to Bruno's axp20x_ac_power.c is the additional
> check on a possible short-circuit between ACIN and VBUS. In this
> case, axp20x-ac-power-supply refuses to attach itself to the device
> and axp20x-usb-power-supply must be used.
>
> [0] http://permalink.gmane.org/gmane.comp.hardware.netbook.arm.sunxi/17980
>
> Signed-off-by: Michael Haas <haas-bdq14YP6qtSV9CzYT+GlPGD2FQJk+8+b@public.gmane.org>
> ---
> drivers/mfd/axp20x.c | 11 +++
> drivers/power/Makefile | 2 +-
> drivers/power/axp20x_ac_power.c | 212 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 224 insertions(+), 1 deletion(-)
> create mode 100644 drivers/power/axp20x_ac_power.c
>
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index a57d6e9..9351c0e 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -178,6 +178,12 @@ static struct resource axp288_power_button_resources[] = {
> },
> };
>
> +static struct resource axp20x_ac_power_supply_resources[] = {
> + DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_ACIN_PLUGIN, "ACIN_PLUGIN"),
> + DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_ACIN_REMOVAL, "ACIN_REMOVAL"),
> + DEFINE_RES_IRQ_NAMED(AXP20X_IRQ_ACIN_OVER_V, "ACIN_OVER_V"),
> +};
> +
> static struct resource axp288_fuel_gauge_resources[] = {
> {
> .start = AXP288_IRQ_QWBTU,
> @@ -440,6 +446,11 @@ static struct mfd_cell axp20x_cells[] = {
> .of_compatible = "x-powers,axp202-usb-power-supply",
> .num_resources = ARRAY_SIZE(axp20x_usb_power_supply_resources),
> .resources = axp20x_usb_power_supply_resources,
> + }, {
> + .name = "axp20x-ac-power-supply",
> + .of_compatible = "x-powers,axp202-ac-power-supply",
> + .num_resources = ARRAY_SIZE(axp20x_ac_power_supply_resources),
> + .resources = axp20x_ac_power_supply_resources,
> },
> };
>

These changes should be in a separate patch.

> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> index e46b75d..3a785cc 100644
> --- a/drivers/power/Makefile
> +++ b/drivers/power/Makefile
> @@ -9,7 +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-$(CONFIG_AXP20X_POWER) += axp20x_usb_power.o axp20x_ac_power.o
> obj-$(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_ac_power.c b/drivers/power/axp20x_ac_power.c
> new file mode 100644
> index 0000000..c5bcbeb
> --- /dev/null
> +++ b/drivers/power/axp20x_ac_power.c
> @@ -0,0 +1,212 @@
> +/*
> + * AXP20x PMIC AC power driver
> + *
> + * Copyright 2014-2015 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/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.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-ac-power"
> +/* Fields of AXP20X_PWR_INPUT_STATUS */
> +#define AXP20X_PWR_STATUS_AC_PRESENT BIT(7)
> +#define AXP20X_PWR_STATUS_AC_AVAILABLE BIT(6)
> +#define AXP20X_PWR_STATUS_AC_VBUS_SHORT BIT(1)
> +#define AXP20X_PWR_STATUS_AC_VBUS_SEL BIT(0)
> +
> +/* Fields of AXP20X_ADC_EN1 */
> +#define AXP20X_ADC_EN1_ACIN_VOLT BIT(5)
> +#define AXP20X_ADC_EN1_ACIN_CURR BIT(4)

That should probably be defined in the global header, next to the
registers.

> +struct axp20x_ac_power {
> + struct regmap *regmap;
> + struct power_supply *supply;
> +};
> +
> +static int axp20x_ac_power_get_property(struct power_supply *psy,
> + enum power_supply_property psp, union power_supply_propval *val)

The alignment is supposed to be on the opening parentheses

> +{
> + struct axp20x_ac_power *power = power_supply_get_drvdata(psy);
> + unsigned int input;
> + int r;
> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> + r = axp20x_read_variable_width(power->regmap,
> + AXP20X_ACIN_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_NOW:
> + r = axp20x_read_variable_width(power->regmap,
> + AXP20X_ACIN_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_PRESENT:
> + val->intval = !!(input & AXP20X_PWR_STATUS_AC_PRESENT);
> + break;
> + case POWER_SUPPLY_PROP_ONLINE:
> + val->intval = !!(input & AXP20X_PWR_STATUS_AC_AVAILABLE);
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static enum power_supply_property axp20x_ac_power_properties[] = {
> + POWER_SUPPLY_PROP_PRESENT,
> + POWER_SUPPLY_PROP_ONLINE,
> + POWER_SUPPLY_PROP_VOLTAGE_NOW,
> + POWER_SUPPLY_PROP_CURRENT_NOW,
> +};
> +
> +static const struct power_supply_desc axp20x_ac_power_desc = {
> + .name = "axp20x-ac",
> + .type = POWER_SUPPLY_TYPE_MAINS,
> + .properties = axp20x_ac_power_properties,
> + .num_properties = ARRAY_SIZE(axp20x_ac_power_properties),
> + .get_property = axp20x_ac_power_get_property,
> +};
> +
> +static irqreturn_t axp20x_irq_ac_over_v(int irq, void *devid)
> +{
> + struct axp20x_ac_power *power = devid;
> +
> + dev_warn(&power->supply->dev, "IRQ#%d AC over voltage\n", irq);
> + power_supply_changed(power->supply);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t axp20x_irq_ac_plugin(int irq, void *devid)
> +{
> + struct axp20x_ac_power *power = devid;
> +
> + dev_info(&power->supply->dev, "IRQ#%d AC connected\n", irq);
> + power_supply_changed(power->supply);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t axp20x_irq_ac_removal(int irq, void *devid)
> +{
> + struct axp20x_ac_power *power = devid;
> +
> + dev_info(&power->supply->dev, "IRQ#%d AC disconnected\n", irq);
> + power_supply_changed(power->supply);
> +
> + return IRQ_HANDLED;
> +}

Logging in the interrupt handler is usually a bad idea, for several
reasons:
- If you have a console, it's going to be output on the console,
which might take quite some time. And you don't want to take
quite some time in the interrupt handler.
- printk might not even work in the interrupt context in some
scenarios.

Removing that handler, you can register the same interrupt handler on
all the interrupts.

> +static int axp20x_ac_power_probe(struct platform_device *pdev)
> +{
> + struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
> + struct power_supply_config psy_cfg = {};
> + struct axp20x_ac_power *power;
> + static const char * const irq_names[] = { "ACIN_PLUGIN",
> + "ACIN_REMOVAL", "ACIN_OVER_V" };
> + irqreturn_t (*irq_funcs[])(int, void *) = { axp20x_irq_ac_plugin,
> + axp20x_irq_ac_removal, axp20x_irq_ac_over_v };
> + int i, irq, r, input;
> +
> + if (!of_device_is_available(pdev->dev.of_node))
> + return -ENODEV;

That's useless. If the device is not available, you're not going to be
probed in the first place.

> + power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
> + if (!power)
> + return -ENOMEM;
> +
> + power->regmap = axp20x->regmap;
> +
> + r = regmap_read(power->regmap, AXP20X_PWR_INPUT_STATUS, &input);
> + if (r < 0)
> + return r;
> +
> + if (!!(input & AXP20X_PWR_STATUS_AC_VBUS_SHORT)) {
> + dev_err(&pdev->dev, "AC is connected to VBUS. Use axp20x_usb_power-supply driver instead!");
> + return -ENODEV;
> + }

Can't that change over time? Can't we support both drivers at the same time?

> + /* Enable ac voltage and current measurement */
> + r = regmap_update_bits(power->regmap, AXP20X_ADC_EN1,
> + AXP20X_ADC_EN1_ACIN_CURR | AXP20X_ADC_EN1_ACIN_VOLT,
> + AXP20X_ADC_EN1_ACIN_CURR | AXP20X_ADC_EN1_ACIN_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_ac_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,
> + irq_funcs[i], 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_ac_power_match[] = {
> + { .compatible = "x-powers,axp202-ac-power-supply" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, axp20x_ac_power_match);
> +
> +static struct platform_driver axp20x_ac_power_driver = {
> + .probe = axp20x_ac_power_probe,
> + .driver = {
> + .name = DRVNAME,
> + .of_match_table = axp20x_ac_power_match,
> + },
> +};
> +
> +module_platform_driver(axp20x_ac_power_driver);
> +
> +MODULE_AUTHOR("Bruno Prémont <bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org>");
> +MODULE_DESCRIPTION("AXP20x PMIC AC power supply status driver");
> +MODULE_LICENSE("GPL");
> --
> 2.8.0

Thanks!
Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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