On Thu, Sep 13, 2018 at 02:43:35PM -0700, Matt Ranostay wrote: > On Wed, Sep 12, 2018 at 8:51 PM Song Qiang <songqiang1304521@xxxxxxxxx> wrote: > > > > This driver tries to access a block of data on a i2c bus and it tries > > to manually make a device command frame and a consecutively read frame, > > then uses i2c_transfer() to read data. But this has already been > > implemented in i2c_smbus_read_i2c_block_data(). > > Sorry for not having this device by my hand, which is a little expansive > > for me, but I have another i2c device and tested with both i2c_transfer() > > and i2c_smbus_read_i2c_block_data() and they all ends the same. > > I'm not familiar with the SMBus, don't know if the lidar_smbus_xfer() > > function is the same as i2c_smbus_read_block_data()? The original code > > is commented with something I'm not sure, but I think if it's a standard > > SMBus, it should be able to use in here. > > Hoping for someone to explain. > > > > Yes actually there is a reason for this insanity! > > It isn't actually SMBUS (note the lidar_smbus_xfer function below it) > and has a odd way to read registers via I2C. > Basically the I2C_M_STOP flags is the reason you can use the standard > i2c_smbus_read_i2c_block_data(). > > Page 6 in this datasheet > * http://static.garmin.com/pumac/LIDAR_Lite_v3_Operation_Manual_and_Technical_Specifications.pdf > > > Signed-off-by: Song Qiang <songqiang.1304521@xxxxxxxxx> > > --- > > .../iio/proximity/pulsedlight-lidar-lite-v2.c | 18 +----------------- > > 1 file changed, 1 insertion(+), 17 deletions(-) > > > > diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c > > index 47af54f14756..ca880ba8e820 100644 > > --- a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c > > +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c > > @@ -63,23 +63,7 @@ static const struct iio_chan_spec lidar_channels[] = { > > > > 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 *) ® > > - > > - 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 : -EIO; > > + return i2c_smbus_read_i2c_block_data(data->client, reg, len, val); > > } > > > > static int lidar_smbus_xfer(struct lidar_data *data, u8 reg, u8 *val, int len) > > -- > > 2.17.1 > > Hi Matt, Thanks for the explanition, now I understand why we have to use lidar_smbus_xfer() here. So we can use the standard i2c_smbus_read_i2c_block_data() here? I'm thinking since you are the author it seems like you have the hardware, would you mind to test if it's working? I'd appriciate that. yours, Song Qiang
