1 files changed, 125 insertions, 26 deletions

diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
index e544fcfd5ced..93e29fb67fa0 100644
--- a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
+++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
@@ -13,7 +13,7 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
  *
- * TODO: runtime pm, interrupt mode, and signal strength reporting
+ * TODO: interrupt mode, and signal strength reporting
  */
 
 #include <linux/err.h>
@@ -21,6 +21,7 @@
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/buffer.h>
@@ -35,8 +36,11 @@
 #define LIDAR_REG_STATUS_INVALID	BIT(3)
 #define LIDAR_REG_STATUS_READY		BIT(0)
 
-#define LIDAR_REG_DATA_HBYTE	0x0f
-#define LIDAR_REG_DATA_LBYTE	0x10
+#define LIDAR_REG_DATA_HBYTE		0x0f
+#define LIDAR_REG_DATA_LBYTE		0x10
+#define LIDAR_REG_DATA_WORD_READ	BIT(7)
+
+#define LIDAR_REG_PWR_CONTROL	0x65
 
 #define LIDAR_DRV_NAME "lidar"
 
@@ -44,6 +48,9 @@ struct lidar_data {
 	struct iio_dev *indio_dev;
 	struct i2c_client *client;
 
+	int (*xfer)(struct lidar_data *data, u8 reg, u8 *val, int len);
+	int i2c_enabled;
+
 	u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */
 };
 
@@ -62,7 +69,28 @@ static const struct iio_chan_spec lidar_channels[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(1),
 };
 
-static int lidar_read_byte(struct lidar_data *data, int reg)
+static int lidar_i2c_xfer(struct lidar_data *data, u8 reg, u8 *val, int len)
+{
+	struct i2c_client *client = data->client;
+	struct i2c_msg msg[2];
+	int ret;
+
+	msg[0].addr = client->addr;
+	msg[0].flags = client->flags | I2C_M_STOP;
+	msg[0].len = 1;
+	msg[0].buf  = (char *) &reg;
+
+	msg[1].addr = client->addr;
+	msg[1].flags = client->flags | I2C_M_RD;
+	msg[1].len = len;
+	msg[1].buf = (char *) val;
+
+	ret = i2c_transfer(client->adapter, msg, 2);
+
+	return (ret == 2) ? 0 : ret;
+}
+
+static int lidar_smbus_xfer(struct lidar_data *data, u8 reg, u8 *val, int len)
 {
 	struct i2c_client *client = data->client;
 	int ret;
@@ -72,17 +100,35 @@ static int lidar_read_byte(struct lidar_data *data, int reg)
 	 * so in turn i2c_smbus_read_byte_data cannot be used
 	 */
 
-	ret = i2c_smbus_write_byte(client, reg);
-	if (ret < 0) {
-		dev_err(&client->dev, "cannot write addr value");
-		return ret;
+	while (len--) {
+		ret = i2c_smbus_write_byte(client, reg++);
+		if (ret < 0) {
+			dev_err(&client->dev, "cannot write addr value");
+			return ret;
+		}
+
+		ret = i2c_smbus_read_byte(client);
+		if (ret < 0) {
+			dev_err(&client->dev, "cannot read data value");
+			return ret;
+		}
+
+		*(val++) = ret;
 	}
 
-	ret = i2c_smbus_read_byte(client);
+	return 0;
+}
+
+static int lidar_read_byte(struct lidar_data *data, u8 reg)
+{
+	int ret;
+	u8 val;
+
+	ret = data->xfer(data, reg, &val, 1);
 	if (ret < 0)
-		dev_err(&client->dev, "cannot read data value");
+		return ret;
 
-	return ret;
+	return val;
 }
 
 static inline int lidar_write_control(struct lidar_data *data, int val)
@@ -90,24 +136,22 @@ static inline int lidar_write_control(struct lidar_data *data, int val)
 	return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
 }
 
-static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
+static inline int lidar_write_power(struct lidar_data *data, int val)
 {
-	int ret;
-	int val;
-
-	ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE);
-	if (ret < 0)
-		return ret;
-	val = ret << 8;
+	return i2c_smbus_write_byte_data(data->client,
+					 LIDAR_REG_PWR_CONTROL, val);
+}
 
-	ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE);
-	if (ret < 0)
-		return ret;
+static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
+{
+	int ret = data->xfer(data, LIDAR_REG_DATA_HBYTE |
+			(data->i2c_enabled ? LIDAR_REG_DATA_WORD_READ : 0),
+			(u8 *) reg, 2);
 
-	val |= ret;
-	*reg = val;
+	if (!ret)
+		*reg = be16_to_cpu(*reg);
 
-	return 0;
+	return ret;
 }
 
 static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
@@ -116,6 +160,8 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
 	int tries = 10;
 	int ret;
 
+	pm_runtime_get_sync(&client->dev);
+
 	/* start sample */
 	ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
 	if (ret < 0) {
@@ -144,6 +190,8 @@ static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
 		}
 		ret = -EIO;
 	}
+	pm_runtime_mark_last_busy(&client->dev);
+	pm_runtime_put_autosuspend(&client->dev);
 
 	return ret;
 }
@@ -221,6 +269,16 @@ static int lidar_probe(struct i2c_client *client,
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
+	data = iio_priv(indio_dev);
+
+	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		data->xfer = lidar_i2c_xfer;
+		data->i2c_enabled = 1;
+	} else if (i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
+		data->xfer = lidar_smbus_xfer;
+	else
+		return -ENOTSUPP;
 
 	indio_dev->info = &lidar_info;
 	indio_dev->name = LIDAR_DRV_NAME;
@@ -228,7 +286,6 @@ static int lidar_probe(struct i2c_client *client,
 	indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	data = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 
 	data->client = client;
@@ -243,6 +300,17 @@ static int lidar_probe(struct i2c_client *client,
 	if (ret)
 		goto error_unreg_buffer;
 
+	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
+	pm_runtime_use_autosuspend(&client->dev);
+
+	ret = pm_runtime_set_active(&client->dev);
+	if (ret)
+		goto error_unreg_buffer;
+	pm_runtime_enable(&client->dev);
+
+	pm_runtime_mark_last_busy(&client->dev);
+	pm_runtime_idle(&client->dev);
+
 	return 0;
 
 error_unreg_buffer:
@@ -258,6 +326,9 @@ static int lidar_remove(struct i2c_client *client)
 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 
+	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+
 	return 0;
 }
 
@@ -273,10 +344,38 @@ static const struct of_device_id lidar_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, lidar_dt_ids);
 
+#ifdef CONFIG_PM
+static int lidar_pm_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct lidar_data *data = iio_priv(indio_dev);
+
+	return lidar_write_power(data, 0x0f);
+}
+
+static int lidar_pm_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct lidar_data *data = iio_priv(indio_dev);
+	int ret = lidar_write_power(data, 0);
+
+	/* regulator and FPGA needs settling time */
+	usleep_range(15000, 20000);
+
+	return ret;
+}
+#endif
+
+static const struct dev_pm_ops lidar_pm_ops = {
+	SET_RUNTIME_PM_OPS(lidar_pm_runtime_suspend,
+			   lidar_pm_runtime_resume, NULL)
+};
+
 static struct i2c_driver lidar_driver = {
 	.driver = {
 		.name	= LIDAR_DRV_NAME,
 		.of_match_table	= of_match_ptr(lidar_dt_ids),
+		.pm	= &lidar_pm_ops,
 	},
 	.probe		= lidar_probe,
 	.remove		= lidar_remove,