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authorMatt Ranostay <mranostay@gmail.com>2015-12-02 08:47:20 +0300
committerJonathan Cameron <jic23@kernel.org>2015-12-03 21:31:12 +0300
commit93e87d73cc46685902bffb0928c2514eaf209b44 (patch)
tree42e53f8a2825efcc963df9098943415319f52c0d /drivers/iio/chemical
parent4c3e2a4036054deca4819758f59ff65f27938388 (diff)
downloadlinux-93e87d73cc46685902bffb0928c2514eaf209b44.tar.xz
iio: chemical: vz89x: rework i2c transfer reading
Add an optimized i2c transfer reading function, and fallback to racey smbus transfers if client->adapter doesn't support this. Signed-off-by: Matt Ranostay <mranostay@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/chemical')
-rw-r--r--drivers/iio/chemical/vz89x.c66
1 files changed, 52 insertions, 14 deletions
diff --git a/drivers/iio/chemical/vz89x.c b/drivers/iio/chemical/vz89x.c
index 11e59a5a5112..b8b804923230 100644
--- a/drivers/iio/chemical/vz89x.c
+++ b/drivers/iio/chemical/vz89x.c
@@ -34,8 +34,9 @@
struct vz89x_data {
struct i2c_client *client;
struct mutex lock;
- unsigned long last_update;
+ int (*xfer)(struct vz89x_data *data, u8 cmd);
+ unsigned long last_update;
u8 buffer[VZ89X_REG_MEASUREMENT_SIZE];
};
@@ -100,27 +101,60 @@ static int vz89x_measurement_is_valid(struct vz89x_data *data)
return !!(data->buffer[VZ89X_REG_MEASUREMENT_SIZE - 1] > 0);
}
-static int vz89x_get_measurement(struct vz89x_data *data)
+static int vz89x_i2c_xfer(struct vz89x_data *data, u8 cmd)
{
+ struct i2c_client *client = data->client;
+ struct i2c_msg msg[2];
int ret;
- int i;
+ u8 buf[3] = { cmd, 0, 0};
- /* sensor can only be polled once a second max per datasheet */
- if (!time_after(jiffies, data->last_update + HZ))
- return 0;
+ msg[0].addr = client->addr;
+ msg[0].flags = client->flags;
+ msg[0].len = 3;
+ msg[0].buf = (char *) &buf;
+
+ msg[1].addr = client->addr;
+ msg[1].flags = client->flags | I2C_M_RD;
+ msg[1].len = VZ89X_REG_MEASUREMENT_SIZE;
+ msg[1].buf = (char *) &data->buffer;
+
+ ret = i2c_transfer(client->adapter, msg, 2);
- ret = i2c_smbus_write_word_data(data->client,
- VZ89X_REG_MEASUREMENT, 0);
+ return (ret == 2) ? 0 : ret;
+}
+
+static int vz89x_smbus_xfer(struct vz89x_data *data, u8 cmd)
+{
+ struct i2c_client *client = data->client;
+ int ret;
+ int i;
+
+ ret = i2c_smbus_write_word_data(client, cmd, 0);
if (ret < 0)
return ret;
for (i = 0; i < VZ89X_REG_MEASUREMENT_SIZE; i++) {
- ret = i2c_smbus_read_byte(data->client);
+ ret = i2c_smbus_read_byte(client);
if (ret < 0)
return ret;
data->buffer[i] = ret;
}
+ return 0;
+}
+
+static int vz89x_get_measurement(struct vz89x_data *data)
+{
+ int ret;
+
+ /* sensor can only be polled once a second max per datasheet */
+ if (!time_after(jiffies, data->last_update + HZ))
+ return 0;
+
+ ret = data->xfer(data, VZ89X_REG_MEASUREMENT);
+ if (ret < 0)
+ return ret;
+
ret = vz89x_measurement_is_valid(data);
if (ret)
return -EAGAIN;
@@ -204,15 +238,19 @@ static int vz89x_probe(struct i2c_client *client,
struct iio_dev *indio_dev;
struct vz89x_data *data;
- if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
- I2C_FUNC_SMBUS_BYTE))
- return -ENODEV;
-
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 = vz89x_i2c_xfer;
+ else if (i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
+ data->xfer = vz89x_smbus_xfer;
+ else
+ return -ENOTSUPP;
+
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->last_update = jiffies - HZ;