iio: make st_sensors drivers use regmap

This patch is meant to replace the i2c/spi transfer functions with
regmap. SPI framework requires DMA safe buffers so let's add GFP_DMA
flag for memory allocation used by bulk_read functions.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 35 insertions, 38 deletions

diff --git a/drivers/iio/common/st_sensors/st_sensors_i2c.c b/drivers/iio/common/st_sensors/st_sensors_i2c.c
index b1c9812407e7..9240625534df 100644
--- a/drivers/iio/common/st_sensors/st_sensors_i2c.c
+++ b/drivers/iio/common/st_sensors/st_sensors_i2c.c
@@ -13,6 +13,7 @@
 #include <linux/iio/iio.h>
 #include <linux/of_device.h>
 #include <linux/acpi.h>
+#include <linux/regmap.h>
 
 #include <linux/iio/common/st_sensors_i2c.h>
 
@@ -26,55 +27,51 @@ static unsigned int st_sensors_i2c_get_irq(struct iio_dev *indio_dev)
 	return to_i2c_client(sdata->dev)->irq;
 }
 
-static int st_sensors_i2c_read_byte(struct st_sensor_transfer_buffer *tb,
-				struct device *dev, u8 reg_addr, u8 *res_byte)
-{
-	int err;
-
-	err = i2c_smbus_read_byte_data(to_i2c_client(dev), reg_addr);
-	if (err < 0)
-		goto st_accel_i2c_read_byte_error;
-
-	*res_byte = err & 0xff;
-
-st_accel_i2c_read_byte_error:
-	return err < 0 ? err : 0;
-}
-
-static int st_sensors_i2c_read_multiple_byte(
-		struct st_sensor_transfer_buffer *tb, struct device *dev,
-			u8 reg_addr, int len, u8 *data, bool multiread_bit)
-{
-	if (multiread_bit)
-		reg_addr |= ST_SENSORS_I2C_MULTIREAD;
-
-	return i2c_smbus_read_i2c_block_data_or_emulated(to_i2c_client(dev),
-							 reg_addr, len, data);
-}
-
-static int st_sensors_i2c_write_byte(struct st_sensor_transfer_buffer *tb,
-				struct device *dev, u8 reg_addr, u8 data)
-{
-	return i2c_smbus_write_byte_data(to_i2c_client(dev), reg_addr, data);
-}
+static const struct regmap_config st_sensors_i2c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
 
-static const struct st_sensor_transfer_function st_sensors_tf_i2c = {
-	.read_byte = st_sensors_i2c_read_byte,
-	.write_byte = st_sensors_i2c_write_byte,
-	.read_multiple_byte = st_sensors_i2c_read_multiple_byte,
+static const struct regmap_config st_sensors_i2c_regmap_multiread_bit_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.read_flag_mask = ST_SENSORS_I2C_MULTIREAD,
 };
 
-void st_sensors_i2c_configure(struct iio_dev *indio_dev,
-		struct i2c_client *client, struct st_sensor_data *sdata)
+/*
+ * st_sensors_i2c_configure() - configure I2C interface
+ * @indio_dev: IIO device reference.
+ * @client: i2c client reference.
+ *
+ * Return: 0 on success, else a negative error code.
+ */
+int st_sensors_i2c_configure(struct iio_dev *indio_dev,
+			     struct i2c_client *client)
 {
+	struct st_sensor_data *sdata = iio_priv(indio_dev);
+	const struct regmap_config *config;
+
+	if (sdata->sensor_settings->multi_read_bit)
+		config = &st_sensors_i2c_regmap_multiread_bit_config;
+	else
+		config = &st_sensors_i2c_regmap_config;
+
+	sdata->regmap = devm_regmap_init_i2c(client, config);
+	if (IS_ERR(sdata->regmap)) {
+		dev_err(&client->dev, "Failed to register i2c regmap (%d)\n",
+			(int)PTR_ERR(sdata->regmap));
+		return PTR_ERR(sdata->regmap);
+	}
+
 	i2c_set_clientdata(client, indio_dev);
 
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->name = client->name;
 
 	sdata->dev = &client->dev;
-	sdata->tf = &st_sensors_tf_i2c;
 	sdata->get_irq_data_ready = st_sensors_i2c_get_irq;
+
+	return 0;
 }
 EXPORT_SYMBOL(st_sensors_i2c_configure);