mfd: axp20x: Split the driver into core and i2c bits

The axp20x driver assumes the device is i2c based. This is not the
case with later chips, which use a proprietary 2 wire serial bus
by Allwinner called "Reduced Serial Bus".

This patch follows the example of mfd/wm831x and splits it into
an interface independent core, and an i2c specific glue layer.
MFD_AXP20X and the new MFD_AXP20X_I2C are changed to tristate
symbols, allowing the driver to be built as modules.

Whitespace and other style errors in the moved i2c specific code
have been fixed. Included but unused header files are removed as
well.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -91,14 +91,18 @@ config MFD_BCM590XX
 	  Support for the BCM590xx PMUs from Broadcom
 
 config MFD_AXP20X
-	bool "X-Powers AXP20X"
+	tristate
 	select MFD_CORE
-	select REGMAP_I2C
 	select REGMAP_IRQ
-	depends on I2C=y
+
+config MFD_AXP20X_I2C
+	tristate "X-Powers AXP series PMICs with I2C"
+	select MFD_AXP20X
+	select REGMAP_I2C
+	depends on I2C
 	help
-	  If you say Y here you get support for the X-Powers AXP202, AXP209 and
-	  AXP288 power management IC (PMIC).
+	  If you say Y here you get support for the X-Powers AXP series power
+	  management ICs (PMICs) controlled with I2C.
 	  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.

drivers/mfd/Makefile

@@ -111,6 +111,7 @@ 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_AXP20X_I2C)	+= axp20x-i2c.o
 
 obj-$(CONFIG_MFD_LP3943)	+= lp3943.o
 obj-$(CONFIG_MFD_LP8788)	+= lp8788.o lp8788-irq.o

drivers/mfd/axp20x-i2c.c

+/*
+ * I2C driver for the X-Powers' Power Management ICs
+ *
+ * AXP20x typically comprises an adaptive USB-Compatible PWM charger, BUCK DC-DC
+ * converters, LDOs, multiple 12-bit ADCs of voltage, current and temperature
+ * as well as configurable GPIOs.
+ *
+ * This driver supports the I2C variants.
+ *
+ * Copyright (C) 2014 Carlo Caione
+ *
+ * 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/acpi.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mfd/axp20x.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+static int axp20x_i2c_probe(struct i2c_client *i2c,
+			    const struct i2c_device_id *id)
+{
+	struct axp20x_dev *axp20x;
+	int ret;
+
+	axp20x = devm_kzalloc(&i2c->dev, sizeof(*axp20x), GFP_KERNEL);
+	if (!axp20x)
+		return -ENOMEM;
+
+	axp20x->dev = &i2c->dev;
+	axp20x->irq = i2c->irq;
+	dev_set_drvdata(axp20x->dev, axp20x);
+
+	ret = axp20x_match_device(axp20x);
+	if (ret)
+		return ret;
+
+	axp20x->regmap = devm_regmap_init_i2c(i2c, axp20x->regmap_cfg);
+	if (IS_ERR(axp20x->regmap)) {
+		ret = PTR_ERR(axp20x->regmap);
+		dev_err(&i2c->dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
+	return axp20x_device_probe(axp20x);
+}
+
+static int axp20x_i2c_remove(struct i2c_client *i2c)
+{
+	struct axp20x_dev *axp20x = i2c_get_clientdata(i2c);
+
+	return axp20x_device_remove(axp20x);
+}
+
+static const struct of_device_id axp20x_i2c_of_match[] = {
+	{ .compatible = "x-powers,axp152", .data = (void *)AXP152_ID },
+	{ .compatible = "x-powers,axp202", .data = (void *)AXP202_ID },
+	{ .compatible = "x-powers,axp209", .data = (void *)AXP209_ID },
+	{ .compatible = "x-powers,axp221", .data = (void *)AXP221_ID },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, axp20x_i2c_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 acpi_device_id axp20x_i2c_acpi_match[] = {
+	{
+		.id = "INT33F4",
+		.driver_data = AXP288_ID,
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, axp20x_i2c_acpi_match);
+
+static struct i2c_driver axp20x_i2c_driver = {
+	.driver = {
+		.name	= "axp20x-i2c",
+		.of_match_table	= of_match_ptr(axp20x_i2c_of_match),
+		.acpi_match_table = ACPI_PTR(axp20x_i2c_acpi_match),
+	},
+	.probe		= axp20x_i2c_probe,
+	.remove		= axp20x_i2c_remove,
+	.id_table	= axp20x_i2c_id,
+};
+
+module_i2c_driver(axp20x_i2c_driver);
+
+MODULE_DESCRIPTION("PMIC MFD I2C driver for AXP20X");
+MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
+MODULE_LICENSE("GPL");

drivers/mfd/axp20x.c

 /*
- * axp20x.c - MFD core driver for the X-Powers' Power Management ICs
+ * MFD core driver for the X-Powers' Power Management ICs
  *
  * AXP20x typically comprises an adaptive USB-Compatible PWM charger, BUCK DC-DC
  * converters, LDOs, multiple 12-bit ADCs of voltage, current and temperature
  * as well as configurable GPIOs.
  *
+ * This file contains the interface independent core functions.
+ *
  * Copyright (C) 2014 Carlo Caione
  *
  * Author: Carlo Caione <carlo@caione.org>
@@ -15,18 +17,15 @@
  */
 
 #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>
 #include <linux/acpi.h>
 
 #define AXP20X_OFF	0x80
@@ -378,32 +377,6 @@ static const struct regmap_irq axp288_regmap_irqs[] = {
 	INIT_REGMAP_IRQ(AXP288, BC_USB_CHNG,            5, 1),
 };
 
-static const struct of_device_id axp20x_of_match[] = {
-	{ .compatible = "x-powers,axp152", .data = (void *) AXP152_ID },
-	{ .compatible = "x-powers,axp202", .data = (void *) AXP202_ID },
-	{ .compatible = "x-powers,axp209", .data = (void *) AXP209_ID },
-	{ .compatible = "x-powers,axp221", .data = (void *) AXP221_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 acpi_device_id axp20x_acpi_match[] = {
-	{
-		.id = "INT33F4",
-		.driver_data = AXP288_ID,
-	},
-	{ },
-};
-MODULE_DEVICE_TABLE(acpi, axp20x_acpi_match);
-
 static const struct regmap_irq_chip axp152_regmap_irq_chip = {
 	.name			= "axp152_irq_chip",
 	.status_base		= AXP152_IRQ1_STATE,
@@ -608,7 +581,7 @@ static void axp20x_power_off(void)
 		     AXP20X_OFF);
 }
 
-static int axp20x_match_device(struct axp20x_dev *axp20x)
+int axp20x_match_device(struct axp20x_dev *axp20x)
 {
 	struct device *dev = axp20x->dev;
 	const struct acpi_device_id *acpi_id;
@@ -665,38 +638,18 @@ static int axp20x_match_device(struct axp20x_dev *axp20x)
 
 	return 0;
 }
+EXPORT_SYMBOL(axp20x_match_device);
 
-static int axp20x_i2c_probe(struct i2c_client *i2c,
-			 const struct i2c_device_id *id)
+int axp20x_device_probe(struct axp20x_dev *axp20x)
 {
-	struct axp20x_dev *axp20x;
 	int ret;
 
-	axp20x = devm_kzalloc(&i2c->dev, sizeof(*axp20x), GFP_KERNEL);
-	if (!axp20x)
-		return -ENOMEM;
-
-	axp20x->i2c_client = i2c;
-	axp20x->dev = &i2c->dev;
-	dev_set_drvdata(axp20x->dev, axp20x);
-
-	ret = axp20x_match_device(axp20x);
-	if (ret)
-		return ret;
-
-	axp20x->regmap = devm_regmap_init_i2c(i2c, axp20x->regmap_cfg);
-	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,
+	ret = regmap_add_irq_chip(axp20x->regmap, axp20x->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);
+		dev_err(axp20x->dev, "failed to add irq chip: %d\n", ret);
 		return ret;
 	}
 
@@ -704,8 +657,8 @@ static int axp20x_i2c_probe(struct i2c_client *i2c,
 			axp20x->nr_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);
+		dev_err(axp20x->dev, "failed to add MFD devices: %d\n", ret);
+		regmap_del_irq_chip(axp20x->irq, axp20x->regmap_irqc);
 		return ret;
 	}
 
@@ -714,38 +667,25 @@ static int axp20x_i2c_probe(struct i2c_client *i2c,
 		pm_power_off = axp20x_power_off;
 	}
 
-	dev_info(&i2c->dev, "AXP20X driver loaded\n");
+	dev_info(axp20x->dev, "AXP20X driver loaded\n");
 
 	return 0;
 }
+EXPORT_SYMBOL(axp20x_device_probe);
 
-static int axp20x_i2c_remove(struct i2c_client *i2c)
+int axp20x_device_remove(struct axp20x_dev *axp20x)
 {
-	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);
+	regmap_del_irq_chip(axp20x->irq, axp20x->regmap_irqc);
 
 	return 0;
 }
-
-static struct i2c_driver axp20x_i2c_driver = {
-	.driver = {
-		.name	= "axp20x",
-		.of_match_table	= of_match_ptr(axp20x_of_match),
-		.acpi_match_table = ACPI_PTR(axp20x_acpi_match),
-	},
-	.probe		= axp20x_i2c_probe,
-	.remove		= axp20x_i2c_remove,
-	.id_table	= axp20x_i2c_id,
-};
-
-module_i2c_driver(axp20x_i2c_driver);
+EXPORT_SYMBOL(axp20x_device_remove);
 
 MODULE_DESCRIPTION("PMIC MFD core driver for AXP20X");
 MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");

include/linux/mfd/axp20x.h

@@ -396,7 +396,7 @@ enum axp288_irqs {
 
 struct axp20x_dev {
 	struct device			*dev;
-	struct i2c_client		*i2c_client;
+	int				irq;
 	struct regmap			*regmap;
 	struct regmap_irq_chip_data	*regmap_irqc;
 	long				variant;
@@ -462,4 +462,35 @@ static inline int axp20x_read_variable_width(struct regmap *regmap,
 	return result;
 }
 
+/**
+ * axp20x_match_device(): Setup axp20x variant related fields
+ *
+ * @axp20x: axp20x device to setup (.dev field must be set)
+ * @dev: device associated with this axp20x device
+ *
+ * This lets the axp20x core configure the mfd cells and register maps
+ * for later use.
+ */
+int axp20x_match_device(struct axp20x_dev *axp20x);
+
+/**
+ * axp20x_device_probe(): Probe a configured axp20x device
+ *
+ * @axp20x: axp20x device to probe (must be configured)
+ *
+ * This function lets the axp20x core register the axp20x mfd devices
+ * and irqchip. The axp20x device passed in must be fully configured
+ * with axp20x_match_device, its irq set, and regmap created.
+ */
+int axp20x_device_probe(struct axp20x_dev *axp20x);
+
+/**
+ * axp20x_device_probe(): Remove a axp20x device
+ *
+ * @axp20x: axp20x device to remove
+ *
+ * This tells the axp20x core to remove the associated mfd devices
+ */
+int axp20x_device_remove(struct axp20x_dev *axp20x);
+
 #endif /* __LINUX_MFD_AXP20X_H */