From 93e87d73cc46685902bffb0928c2514eaf209b44 Mon Sep 17 00:00:00 2001 From: Matt Ranostay Date: Tue, 1 Dec 2015 21:47:20 -0800 Subject: [PATCH] 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 Signed-off-by: Jonathan Cameron --- drivers/iio/chemical/vz89x.c | 66 ++++++++++++++++++++++++++++-------- 1 file 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; -- 2.34.1