mfd: AXP20x: Add mfd driver for AXP20x PMIC

This patch introduces the preliminary support for PMICs X-Powers AXP202
and AXP209. The AXP209 and AXP202 are the PMUs (Power Management Unit)
used by A10, A13 and A20 SoCs and developed by X-Powers, a sister company
of Allwinner.

The core enables support for two subsystems:
- PEK (Power Enable Key)
- Regulators

Signed-off-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

3 files changed, 271 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index e166d7176d7a..c681741ce492 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -67,6 +67,18 @@ config MFD_BCM590XX
 	help
 	  Support for the BCM590xx PMUs from Broadcom
 
+config MFD_AXP20X
+	bool "X-Powers AXP20X"
+	select MFD_CORE
+	select REGMAP_I2C
+	select REGMAP_IRQ
+	depends on I2C=y
+	help
+	  If you say Y here you get support for the X-Powers AXP202 and AXP209.
+	  This driver include only the core APIs. You have to select individual
+	  components like regulators or the PEK (Power Enable Key) under the
+	  corresponding menus.
+
 config MFD_CROS_EC
 	tristate "ChromeOS Embedded Controller"
 	select MFD_CORE
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 2851275e2656..1efecf2793ae 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_PMIC_DA9052)	+= da9052-irq.o
 obj-$(CONFIG_PMIC_DA9052)	+= da9052-core.o
 obj-$(CONFIG_MFD_DA9052_SPI)	+= da9052-spi.o
 obj-$(CONFIG_MFD_DA9052_I2C)	+= da9052-i2c.o
+obj-$(CONFIG_MFD_AXP20X)	+= axp20x.o
 
 obj-$(CONFIG_MFD_LP3943)	+= lp3943.o
 obj-$(CONFIG_MFD_LP8788)	+= lp8788.o lp8788-irq.o
diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
new file mode 100644
index 000000000000..dee653989e3a
--- /dev/null
+++ b/drivers/mfd/axp20x.c
@@ -0,0 +1,258 @@
+/*
+ * axp20x.c - MFD core driver for the X-Powers AXP202 and AXP209
+ *
+ * AXP20x comprises an adaptive USB-Compatible PWM charger, 2 BUCK DC-DC
+ * converters, 5 LDOs, multiple 12-bit ADCs of voltage, current and temperature
+ * as well as 4 configurable GPIOs.
+ *
+ * Author: Carlo Caione <carlo@caione.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/regulator/consumer.h>
+#include <linux/mfd/axp20x.h>
+#include <linux/mfd/core.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+
+#define AXP20X_OFF	0x80
+
+static const struct regmap_range axp20x_writeable_ranges[] = {
+	regmap_reg_range(AXP20X_DATACACHE(0), AXP20X_IRQ5_STATE),
+	regmap_reg_range(AXP20X_DCDC_MODE, AXP20X_FG_RES),
+};
+
+static const struct regmap_range axp20x_volatile_ranges[] = {
+	regmap_reg_range(AXP20X_IRQ1_EN, AXP20X_IRQ5_STATE),
+};
+
+static const struct regmap_access_table axp20x_writeable_table = {
+	.yes_ranges	= axp20x_writeable_ranges,
+	.n_yes_ranges	= ARRAY_SIZE(axp20x_writeable_ranges),
+};
+
+static const struct regmap_access_table axp20x_volatile_table = {
+	.yes_ranges	= axp20x_volatile_ranges,
+	.n_yes_ranges	= ARRAY_SIZE(axp20x_volatile_ranges),
+};
+
+static struct resource axp20x_pek_resources[] = {
+	{
+		.name	= "PEK_DBR",
+		.start	= AXP20X_IRQ_PEK_RIS_EDGE,
+		.end	= AXP20X_IRQ_PEK_RIS_EDGE,
+		.flags	= IORESOURCE_IRQ,
+	}, {
+		.name	= "PEK_DBF",
+		.start	= AXP20X_IRQ_PEK_FAL_EDGE,
+		.end	= AXP20X_IRQ_PEK_FAL_EDGE,
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static const struct regmap_config axp20x_regmap_config = {
+	.reg_bits	= 8,
+	.val_bits	= 8,
+	.wr_table	= &axp20x_writeable_table,
+	.volatile_table	= &axp20x_volatile_table,
+	.max_register	= AXP20X_FG_RES,
+	.cache_type	= REGCACHE_RBTREE,
+};
+
+#define AXP20X_IRQ(_irq, _off, _mask) \
+	[AXP20X_IRQ_##_irq] = { .reg_offset = (_off), .mask = BIT(_mask) }
+
+static const struct regmap_irq axp20x_regmap_irqs[] = {
+	AXP20X_IRQ(ACIN_OVER_V,		0, 7),
+	AXP20X_IRQ(ACIN_PLUGIN,		0, 6),
+	AXP20X_IRQ(ACIN_REMOVAL,	0, 5),
+	AXP20X_IRQ(VBUS_OVER_V,		0, 4),
+	AXP20X_IRQ(VBUS_PLUGIN,		0, 3),
+	AXP20X_IRQ(VBUS_REMOVAL,	0, 2),
+	AXP20X_IRQ(VBUS_V_LOW,		0, 1),
+	AXP20X_IRQ(BATT_PLUGIN,		1, 7),
+	AXP20X_IRQ(BATT_REMOVAL,	1, 6),
+	AXP20X_IRQ(BATT_ENT_ACT_MODE,	1, 5),
+	AXP20X_IRQ(BATT_EXIT_ACT_MODE,	1, 4),
+	AXP20X_IRQ(CHARG,		1, 3),
+	AXP20X_IRQ(CHARG_DONE,		1, 2),
+	AXP20X_IRQ(BATT_TEMP_HIGH,	1, 1),
+	AXP20X_IRQ(BATT_TEMP_LOW,	1, 0),
+	AXP20X_IRQ(DIE_TEMP_HIGH,	2, 7),
+	AXP20X_IRQ(CHARG_I_LOW,		2, 6),
+	AXP20X_IRQ(DCDC1_V_LONG,	2, 5),
+	AXP20X_IRQ(DCDC2_V_LONG,	2, 4),
+	AXP20X_IRQ(DCDC3_V_LONG,	2, 3),
+	AXP20X_IRQ(PEK_SHORT,		2, 1),
+	AXP20X_IRQ(PEK_LONG,		2, 0),
+	AXP20X_IRQ(N_OE_PWR_ON,		3, 7),
+	AXP20X_IRQ(N_OE_PWR_OFF,	3, 6),
+	AXP20X_IRQ(VBUS_VALID,		3, 5),
+	AXP20X_IRQ(VBUS_NOT_VALID,	3, 4),
+	AXP20X_IRQ(VBUS_SESS_VALID,	3, 3),
+	AXP20X_IRQ(VBUS_SESS_END,	3, 2),
+	AXP20X_IRQ(LOW_PWR_LVL1,	3, 1),
+	AXP20X_IRQ(LOW_PWR_LVL2,	3, 0),
+	AXP20X_IRQ(TIMER,		4, 7),
+	AXP20X_IRQ(PEK_RIS_EDGE,	4, 6),
+	AXP20X_IRQ(PEK_FAL_EDGE,	4, 5),
+	AXP20X_IRQ(GPIO3_INPUT,		4, 3),
+	AXP20X_IRQ(GPIO2_INPUT,		4, 2),
+	AXP20X_IRQ(GPIO1_INPUT,		4, 1),
+	AXP20X_IRQ(GPIO0_INPUT,		4, 0),
+};
+
+static const struct of_device_id axp20x_of_match[] = {
+	{ .compatible = "x-powers,axp202", .data = (void *) AXP202_ID },
+	{ .compatible = "x-powers,axp209", .data = (void *) AXP209_ID },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, axp20x_of_match);
+
+/*
+ * This is useless for OF-enabled devices, but it is needed by I2C subsystem
+ */
+static const struct i2c_device_id axp20x_i2c_id[] = {
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, axp20x_i2c_id);
+
+static const struct regmap_irq_chip axp20x_regmap_irq_chip = {
+	.name			= "axp20x_irq_chip",
+	.status_base		= AXP20X_IRQ1_STATE,
+	.ack_base		= AXP20X_IRQ1_STATE,
+	.mask_base		= AXP20X_IRQ1_EN,
+	.num_regs		= 5,
+	.irqs			= axp20x_regmap_irqs,
+	.num_irqs		= ARRAY_SIZE(axp20x_regmap_irqs),
+	.mask_invert		= true,
+	.init_ack_masked	= true,
+};
+
+static const char * const axp20x_supplies[] = {
+	"acin",
+	"vin2",
+	"vin3",
+	"ldo24in",
+	"ldo3in",
+	"ldo5in",
+};
+
+static struct mfd_cell axp20x_cells[] = {
+	{
+		.name			= "axp20x-pek",
+		.num_resources		= ARRAY_SIZE(axp20x_pek_resources),
+		.resources		= axp20x_pek_resources,
+	}, {
+		.name			= "axp20x-regulator",
+		.parent_supplies	= axp20x_supplies,
+		.num_parent_supplies	= ARRAY_SIZE(axp20x_supplies),
+	},
+};
+
+static struct axp20x_dev *axp20x_pm_power_off;
+static void axp20x_power_off(void)
+{
+	regmap_write(axp20x_pm_power_off->regmap, AXP20X_OFF_CTRL,
+		     AXP20X_OFF);
+}
+
+static int axp20x_i2c_probe(struct i2c_client *i2c,
+			 const struct i2c_device_id *id)
+{
+	struct axp20x_dev *axp20x;
+	const struct of_device_id *of_id;
+	int ret;
+
+	axp20x = devm_kzalloc(&i2c->dev, sizeof(*axp20x), GFP_KERNEL);
+	if (!axp20x)
+		return -ENOMEM;
+
+	of_id = of_match_device(axp20x_of_match, &i2c->dev);
+	if (!of_id) {
+		dev_err(&i2c->dev, "Unable to setup AXP20X data\n");
+		return -ENODEV;
+	}
+	axp20x->variant = (long) of_id->data;
+
+	axp20x->i2c_client = i2c;
+	axp20x->dev = &i2c->dev;
+	dev_set_drvdata(axp20x->dev, axp20x);
+
+	axp20x->regmap = devm_regmap_init_i2c(i2c, &axp20x_regmap_config);
+	if (IS_ERR(axp20x->regmap)) {
+		ret = PTR_ERR(axp20x->regmap);
+		dev_err(&i2c->dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_add_irq_chip(axp20x->regmap, i2c->irq,
+				  IRQF_ONESHOT | IRQF_SHARED, -1,
+				  &axp20x_regmap_irq_chip,
+				  &axp20x->regmap_irqc);
+	if (ret) {
+		dev_err(&i2c->dev, "failed to add irq chip: %d\n", ret);
+		return ret;
+	}
+
+	ret = mfd_add_devices(axp20x->dev, -1, axp20x_cells,
+			      ARRAY_SIZE(axp20x_cells), NULL, 0, NULL);
+
+	if (ret) {
+		dev_err(&i2c->dev, "failed to add MFD devices: %d\n", ret);
+		regmap_del_irq_chip(i2c->irq, axp20x->regmap_irqc);
+		return ret;
+	}
+
+	if (!pm_power_off) {
+		axp20x_pm_power_off = axp20x;
+		pm_power_off = axp20x_power_off;
+	}
+
+	dev_info(&i2c->dev, "AXP20X driver loaded\n");
+
+	return 0;
+}
+
+static int axp20x_i2c_remove(struct i2c_client *i2c)
+{
+	struct axp20x_dev *axp20x = i2c_get_clientdata(i2c);
+
+	if (axp20x == axp20x_pm_power_off) {
+		axp20x_pm_power_off = NULL;
+		pm_power_off = NULL;
+	}
+
+	mfd_remove_devices(axp20x->dev);
+	regmap_del_irq_chip(axp20x->i2c_client->irq, axp20x->regmap_irqc);
+
+	return 0;
+}
+
+static struct i2c_driver axp20x_i2c_driver = {
+	.driver = {
+		.name	= "axp20x",
+		.owner	= THIS_MODULE,
+		.of_match_table	= of_match_ptr(axp20x_of_match),
+	},
+	.probe		= axp20x_i2c_probe,
+	.remove		= axp20x_i2c_remove,
+	.id_table	= axp20x_i2c_id,
+};
+
+module_i2c_driver(axp20x_i2c_driver);
+
+MODULE_DESCRIPTION("PMIC MFD core driver for AXP20X");
+MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
+MODULE_LICENSE("GPL");