[PATCH v3 1/6] mfd: da9150: Add support for Fuel-Gauge

[Adam Thomson <Adam.Thomson.Opensource@diasemi.com>]

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
---

Changes in v3:
 - Use DEFINE_RES_IRQ_NAMED() helper for defining FG IRQ resource.
 - Unwanted new line & comments removed.
 - Remove gotos which can be replaced with straight forward return calls.
 - Add enum for indexing MFD cells list, which is used to assign pdata for FG
   sub-device.
 - Remove use of function pointers for QIF related read/write functions as
   currently only I2C supported, so call I2C functions directly.
 - Fold fg.h contents into core.h.

Changes in v2:
 - Moved temp callback function prototype to be part of power fuel-gauge patch,
   as requested by Lee Jones.

 drivers/mfd/da9150-core.c       | 156 ++++++++++++++++++++++++++++++++++++++--
 include/linux/mfd/da9150/core.h |  19 ++++-
 2 files changed, 167 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/da9150-core.c b/drivers/mfd/da9150-core.c
index 94b9bbd..fccd4d5 100644
--- a/drivers/mfd/da9150-core.c
+++ b/drivers/mfd/da9150-core.c
@@ -23,6 +23,77 @@
 #include <linux/mfd/da9150/core.h>
 #include <linux/mfd/da9150/registers.h>

+/* Raw device access, used for QIF */
+static int da9150_i2c_read_device(struct i2c_client *client, u8 addr, int count,
+				  u8 *buf)
+{
+	struct i2c_msg xfer;
+	int ret;
+
+	/*
+	 * Read is split into two transfers as device expects STOP/START rather
+	 * than repeated start to carry out this kind of access.
+	 */
+
+	/* Write address */
+	xfer.addr = client->addr;
+	xfer.flags = 0;
+	xfer.len = 1;
+	xfer.buf = &addr;
+
+	ret = i2c_transfer(client->adapter, &xfer, 1);
+	if (ret != 1) {
+		if (ret < 0)
+			return ret;
+		else
+			return -EIO;
+	}
+
+	/* Read data */
+	xfer.addr = client->addr;
+	xfer.flags = I2C_M_RD;
+	xfer.len = count;
+	xfer.buf = buf;
+
+	ret = i2c_transfer(client->adapter, &xfer, 1);
+	if (ret == 1)
+		return 0;
+	else if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
+static int da9150_i2c_write_device(struct i2c_client *client, u8 addr,
+				   int count, const u8 *buf)
+{
+	struct i2c_msg xfer;
+	u8 *reg_data;
+	int ret;
+
+	reg_data = kzalloc(1 + count, GFP_KERNEL);
+	if (!reg_data)
+		return -ENOMEM;
+
+	reg_data[0] = addr;
+	memcpy(&reg_data[1], buf, count);
+
+	/* Write address & data */
+	xfer.addr = client->addr;
+	xfer.flags = 0;
+	xfer.len = 1 + count;
+	xfer.buf = reg_data;
+
+	ret = i2c_transfer(client->adapter, &xfer, 1);
+	kfree(reg_data);
+	if (ret == 1)
+		return 0;
+	else if (ret < 0)
+		return ret;
+	else
+		return -EIO;
+}
+
 static bool da9150_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
@@ -107,6 +178,28 @@ static const struct regmap_config da9150_regmap_config = {
 	.volatile_reg = da9150_volatile_reg,
 };

+void da9150_read_qif(struct da9150 *da9150, u8 addr, int count, u8 *buf)
+{
+	int ret;
+
+	ret = da9150_i2c_read_device(da9150->core_qif, addr, count, buf);
+	if (ret < 0)
+		dev_err(da9150->dev, "Failed to read from QIF 0x%x: %d\n",
+			addr, ret);
+}
+EXPORT_SYMBOL_GPL(da9150_read_qif);
+
+void da9150_write_qif(struct da9150 *da9150, u8 addr, int count, const u8 *buf)
+{
+	int ret;
+
+	ret = da9150_i2c_write_device(da9150->core_qif, addr, count, buf);
+	if (ret < 0)
+		dev_err(da9150->dev, "Failed to write to QIF 0x%x: %d\n",
+			addr, ret);
+}
+EXPORT_SYMBOL_GPL(da9150_write_qif);
+
 u8 da9150_reg_read(struct da9150 *da9150, u16 reg)
 {
 	int val, ret;
@@ -297,19 +390,35 @@ static struct resource da9150_charger_resources[] = {
 	},
 };

+static struct resource da9150_fg_resources[] = {
+	DEFINE_RES_IRQ_NAMED(DA9150_IRQ_FG, "FG"),
+};
+
+enum da9150_dev_idx {
+	DA9150_GPADC_IDX = 0,
+	DA9150_CHARGER_IDX,
+	DA9150_FG_IDX,
+};
+
 static struct mfd_cell da9150_devs[] = {
-	{
+	[DA9150_GPADC_IDX] = {
 		.name = "da9150-gpadc",
 		.of_compatible = "dlg,da9150-gpadc",
 		.resources = da9150_gpadc_resources,
 		.num_resources = ARRAY_SIZE(da9150_gpadc_resources),
 	},
-	{
+	[DA9150_CHARGER_IDX] = {
 		.name = "da9150-charger",
 		.of_compatible = "dlg,da9150-charger",
 		.resources = da9150_charger_resources,
 		.num_resources = ARRAY_SIZE(da9150_charger_resources),
 	},
+	[DA9150_FG_IDX] = {
+		.name = "da9150-fuelgauge",
+		.of_compatible = "dlg,da9150-fg",
+		.resources = da9150_fg_resources,
+		.num_resources = ARRAY_SIZE(da9150_fg_resources),
+	},
 };

 static int da9150_probe(struct i2c_client *client,
@@ -317,6 +426,7 @@ static int da9150_probe(struct i2c_client *client,
 {
 	struct da9150 *da9150;
 	struct da9150_pdata *pdata = dev_get_platdata(&client->dev);
+	int qif_addr;
 	int ret;

 	da9150 = devm_kzalloc(&client->dev, sizeof(*da9150), GFP_KERNEL);
@@ -335,16 +445,41 @@ static int da9150_probe(struct i2c_client *client,
 		return ret;
 	}

-	da9150->irq_base = pdata ? pdata->irq_base : -1;
+	/* Setup secondary I2C interface for QIF access */
+	qif_addr = da9150_reg_read(da9150, DA9150_CORE2WIRE_CTRL_A);
+	qif_addr = (qif_addr & DA9150_CORE_BASE_ADDR_MASK) >> 1;
+	qif_addr |= DA9150_QIF_I2C_ADDR_LSB;
+	da9150->core_qif = i2c_new_dummy(client->adapter, qif_addr);
+	if (!da9150->core_qif) {
+		dev_err(da9150->dev, "Failed to attach QIF client\n");
+		return -ENODEV;
+	}
+
+	i2c_set_clientdata(da9150->core_qif, da9150);
+
+	if (pdata) {
+		da9150->irq_base = pdata->irq_base;
+
+		da9150_devs[DA9150_FG_IDX].platform_data = pdata->fg_pdata;
+		da9150_devs[DA9150_FG_IDX].pdata_size =
+			sizeof(struct da9150_fg_pdata);
+	} else {
+		da9150->irq_base = -1;
+	}

 	ret = regmap_add_irq_chip(da9150->regmap, da9150->irq,
 				  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 				  da9150->irq_base, &da9150_regmap_irq_chip,
 				  &da9150->regmap_irq_data);
-	if (ret)
-		return ret;
+	if (ret) {
+		dev_err(da9150->dev, "Failed to add regmap irq chip: %d\n",
+			ret);
+		goto regmap_irq_fail;
+	}
+

 	da9150->irq_base = regmap_irq_chip_get_base(da9150->regmap_irq_data);
+
 	enable_irq_wake(da9150->irq);

 	ret = mfd_add_devices(da9150->dev, -1, da9150_devs,
@@ -352,11 +487,17 @@ static int da9150_probe(struct i2c_client *client,
 			      da9150->irq_base, NULL);
 	if (ret) {
 		dev_err(da9150->dev, "Failed to add child devices: %d\n", ret);
-		regmap_del_irq_chip(da9150->irq, da9150->regmap_irq_data);
-		return ret;
+		goto mfd_fail;
 	}

 	return 0;
+
+mfd_fail:
+	regmap_del_irq_chip(da9150->irq, da9150->regmap_irq_data);
+regmap_irq_fail:
+	i2c_unregister_device(da9150->core_qif);
+
+	return ret;
 }

 static int da9150_remove(struct i2c_client *client)
@@ -365,6 +506,7 @@ static int da9150_remove(struct i2c_client *client)

 	regmap_del_irq_chip(da9150->irq, da9150->regmap_irq_data);
 	mfd_remove_devices(da9150->dev);
+	i2c_unregister_device(da9150->core_qif);

 	return 0;
 }
diff --git a/include/linux/mfd/da9150/core.h b/include/linux/mfd/da9150/core.h
index 76e6689..1bf50ca 100644
--- a/include/linux/mfd/da9150/core.h
+++ b/include/linux/mfd/da9150/core.h
@@ -15,6 +15,7 @@
 #define __DA9150_CORE_H

 #include <linux/device.h>
+#include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/regmap.h>

@@ -46,23 +47,39 @@
 #define DA9150_IRQ_GPADC	19
 #define DA9150_IRQ_WKUP		20

+/* I2C sub-device address */
+#define DA9150_QIF_I2C_ADDR_LSB		0x5
+
+struct da9150_fg_pdata {
+	u32 update_interval;	/* msecs */
+	u8 warn_soc_lvl;	/* % value */
+	u8 crit_soc_lvl;	/* % value */
+};
+
 struct da9150_pdata {
 	int irq_base;
+	struct da9150_fg_pdata *fg_pdata;
 };

 struct da9150 {
 	struct device *dev;
 	struct regmap *regmap;
+	struct i2c_client *core_qif;
+
 	struct regmap_irq_chip_data *regmap_irq_data;
 	int irq;
 	int irq_base;
 };

-/* Device I/O */
+/* Device I/O - Query Interface for FG and standard register access */
+void da9150_read_qif(struct da9150 *da9150, u8 addr, int count, u8 *buf);
+void da9150_write_qif(struct da9150 *da9150, u8 addr, int count, const u8 *buf);
+
 u8 da9150_reg_read(struct da9150 *da9150, u16 reg);
 void da9150_reg_write(struct da9150 *da9150, u16 reg, u8 val);
 void da9150_set_bits(struct da9150 *da9150, u16 reg, u8 mask, u8 val);

 void da9150_bulk_read(struct da9150 *da9150, u16 reg, int count, u8 *buf);
 void da9150_bulk_write(struct da9150 *da9150, u16 reg, int count, const u8 *buf);
+
 #endif /* __DA9150_CORE_H */
--
1.9.3