[PATCH v5] power: bq20z75: devicetree init support

[Rhyland Klein]

Adding support to generate platform data when kernel is configured
through device tree.

Also adding the binding for the TI bq20z75 fuel gadge and the
bq20z75 driver.

v2: Fixed typo in binding description.
v3: Changed to use "ti," properties
    Changed to use single gpio property for battery detect info
    Removed unnecessary call to of_match_device
v4: Squashed Binding and driver changes together.
    Fixed case where CONFIG_OF is not selected, return existing pdata pointer
v5: Fixed MODULE_DEVICE_TABLE to be i2c instead of platform

Acked-by: Grant Likely <grant.likely at secretlab.ca>
Signed-off-by: Rhyland Klein <rklein at nvidia.com>
---
 .../bindings/power_supply/ti_bq20z75.txt           |   23 ++++++
 drivers/power/bq20z75.c                            |   75 ++++++++++++++++++++
 2 files changed, 98 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/power_supply/ti_bq20z75.txt

diff --git a/Documentation/devicetree/bindings/power_supply/ti_bq20z75.txt b/Documentation/devicetree/bindings/power_supply/ti_bq20z75.txt
new file mode 100644
index 0000000..7571294
--- /dev/null
+++ b/Documentation/devicetree/bindings/power_supply/ti_bq20z75.txt
@@ -0,0 +1,23 @@
+TI bq20z75
+~~~~~~~~~~
+
+Required properties :
+ - compatible : "ti,bq20z75"
+
+Optional properties :
+ - ti,i2c-retry-count : The number of times to retry i2c transactions on i2c
+   IO failure.
+ - ti,poll-retry-count : The number of times to try looking for new status
+   after an external change notification.
+ - ti,battery-detect-gpios : The gpio which signals battery detection and
+   a flag specifying its polarity.
+
+Example:
+
+	bq20z75 at b {
+		compatible = "ti,bq20z75";
+		reg = < 0xb >;
+		ti,i2c-retry-count = <2>;
+		ti,poll-retry-count = <10>;
+		ti,battery-detect-gpios = <&gpio-controller 122 1>;
+	}
diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c
index 9c5e5be..4014a2c 100644
--- a/drivers/power/bq20z75.c
+++ b/drivers/power/bq20z75.c
@@ -613,6 +613,78 @@ static void bq20z75_delayed_work(struct work_struct *work)
 	}
 }
 
+#if defined(CONFIG_OF)
+#include <linux/of_device.h>
+static const struct of_device_id bq20z75_dt_ids[] = {
+	{ .compatible = "ti,bq20z75" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, bq20z75_dt_ids);
+
+static struct bq20z75_platform_data *bq20z75_of_populate_pdata(
+	struct i2c_client *client)
+{
+	const struct of_device_id *dtid;
+	struct device_node *of_node = client->dev.of_node;
+	struct bq20z75_platform_data *pdata = client->dev.platform_data;
+	enum of_gpio_flags gpio_flags;
+	int rc;
+	u32 prop;
+
+	/* verify this driver matches this device */
+	if (!of_node)
+		return NULL;
+
+	/* if platform data is set, honor it */
+	if (pdata)
+		return pdata;
+
+	/* first make sure at least one property is set, otherwise
+	 * it won't change behavior from running without pdata.
+	 */
+	if (!of_get_property(of_node, "ti,i2c-retry-count", NULL) &&
+		!of_get_property(of_node, "ti,poll-retry-count", NULL) &&
+		!of_get_property(of_node, "ti,battery-detect-gpios", NULL))
+		goto of_out;
+
+	pdata = devm_kzalloc(&client->dev, sizeof(struct bq20z75_platform_data),
+				GFP_KERNEL);
+	if (!pdata)
+		goto of_out;
+
+	rc = of_property_read_u32(of_node, "ti,i2c-retry-count", &prop);
+	if (!rc)
+		pdata->i2c_retry_count = prop;
+
+	rc = of_property_read_u32(of_node, "ti,poll-retry-count", &prop);
+	if (!rc)
+		pdata->poll_retry_count = prop;
+
+	if (!of_get_property(of_node, "ti,battery-detect-gpios", NULL)) {
+		pdata->battery_detect = -1;
+		goto of_out;
+	}
+
+	pdata->battery_detect = of_get_named_gpio_flags(of_node,
+			"ti,battery-detect-gpios", 0, &gpio_flags);
+
+	if (gpio_flags & OF_GPIO_ACTIVE_LOW)
+		pdata->battery_detect_present = 0;
+	else
+		pdata->battery_detect_present = 1;
+
+of_out:
+	return pdata;
+}
+#else
+#define bq20z75_dt_ids NULL
+static struct bq20z75_platform_data *bq20z75_of_populate_pdata(
+	struct i2c_client *client)
+{
+	return client->dev.platform_data;
+}
+#endif
+
 static int __devinit bq20z75_probe(struct i2c_client *client,
 	const struct i2c_device_id *id)
 {
@@ -642,6 +714,8 @@ static int __devinit bq20z75_probe(struct i2c_client *client,
 	bq20z75_device->power_supply.external_power_changed =
 		bq20z75_external_power_changed;
 
+	pdata = bq20z75_of_populate_pdata(client);
+
 	if (pdata) {
 		bq20z75_device->gpio_detect =
 			gpio_is_valid(pdata->battery_detect);
@@ -775,6 +849,7 @@ static struct i2c_driver bq20z75_battery_driver = {
 	.id_table	= bq20z75_id,
 	.driver = {
 		.name	= "bq20z75-battery",
+		.of_match_table = bq20z75_dt_ids,
 	},
 };
 
-- 
1.7.6