power: Add an axp20x-usb-power driver

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@linux-vserver.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

4 files changed, 280 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index f8758d6febf8..914167e14d2e 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -472,6 +472,13 @@ config CHARGER_RT9455
         help
           Say Y to enable support for Richtek RT9455 battery charger.
 
+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 5752ce818f51..fb4413e5dd37 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 000000000000..421a90b83567
--- /dev/null
+++ b/drivers/power/axp20x_usb_power.c
@@ -0,0 +1,248 @@
+/*
+ * AXP20x PMIC USB power supply status driver
+ *
+ * Copyright (C) 2015 Hans de Goede <hdegoede@redhat.com>
+ * Copyright (C) 2014 Bruno Prémont <bonbons@linux-vserver.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 ret;
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_VOLTAGE_MIN:
+                ret = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
+                if (ret)
+                        return ret;
+
+                val->intval = AXP20X_VBUS_VHOLD_uV(v);
+                return 0;
+        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+                ret = axp20x_read_variable_width(power->regmap,
+                                                 AXP20X_VBUS_V_ADC_H, 12);
+                if (ret < 0)
+                        return ret;
+
+                val->intval = ret * 1700; /* 1 step = 1.7 mV */
+                return 0;
+        case POWER_SUPPLY_PROP_CURRENT_MAX:
+                ret = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
+                if (ret)
+                        return ret;
+
+                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:
+                ret = axp20x_read_variable_width(power->regmap,
+                                                 AXP20X_VBUS_I_ADC_H, 12);
+                if (ret < 0)
+                        return ret;
+
+                val->intval = ret * 375; /* 1 step = 0.375 mA */
+                return 0;
+        default:
+                break;
+        }
+
+        /* All the properties below need the input-status reg value */
+        ret = regmap_read(power->regmap, AXP20X_PWR_INPUT_STATUS, &input);
+        if (ret)
+                return ret;
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_HEALTH:
+                if (!(input & AXP20X_PWR_STATUS_VBUS_PRESENT)) {
+                        val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
+                        break;
+                }
+
+                ret = regmap_read(power->regmap, AXP20X_USB_OTG_STATUS, &v);
+                if (ret)
+                        return ret;
+
+                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, ret;
+
+        if (!of_device_is_available(pdev->dev.of_node))
+                return -ENODEV;
+
+        if (!axp20x) {
+                dev_err(&pdev->dev, "Parent drvdata not set\n");
+                return -EINVAL;
+        }
+
+        power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
+        if (!power)
+                return -ENOMEM;
+
+        power->regmap = axp20x->regmap;
+
+        /* Enable vbus valid checking */
+        ret = regmap_update_bits(power->regmap, AXP20X_VBUS_MON,
+                    AXP20X_VBUS_MON_VBUS_VALID, AXP20X_VBUS_MON_VBUS_VALID);
+        if (ret)
+                return ret;
+
+        /* Enable vbus voltage and current measurement */
+        ret = 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 (ret)
+                return ret;
+
+        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);
+                ret = devm_request_any_context_irq(&pdev->dev, irq,
+                                axp20x_usb_power_irq, 0, DRVNAME, power);
+                if (ret < 0)
+                        dev_warn(&pdev->dev, "Error requesting %s IRQ: %d\n",
+                                 irq_names[i], ret);
+        }
+
+        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@redhat.com>");
+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 cc8ad1e1a307..b24c771cebd5 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 {
         AXP152_ID = 0,
         AXP202_ID,
@@ -438,4 +440,26 @@ 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 */