Messages in this thread Patch in this message | | | From | José Miguel Gonçalves <> | Subject | [PATCH] hwmon: HIH-6130: Support I2C bus drivers without I2C_FUNC_SMBUS_QUICK | Date | Wed, 11 Dec 2013 00:57:42 +0000 |
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Some I2C bus drivers do not allow zero-lenght data transfers which are required to start a mesurement with the HIH6130/1 sensor. Nevertheless, we can overcome this limitation by writing a zero dummy byte. This byte is ignored by the sensor and was verified to be working with the OMAP I2C bus driver in a BeagleBone board.
Signed-off-by: José Miguel Gonçalves <jose.goncalves@inov.pt> --- drivers/hwmon/hih6130.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/hwmon/hih6130.c b/drivers/hwmon/hih6130.c index 2dc37c7..a860cc4 100644 --- a/drivers/hwmon/hih6130.c +++ b/drivers/hwmon/hih6130.c @@ -121,8 +121,20 @@ static int hih6130_update_measurements(struct i2c_client *client) */ if (time_after(jiffies, hih6130->last_update + HZ) || !hih6130->valid) { - /* write to slave address, no data, to request a measurement */ - ret = i2c_master_send(client, tmp, 0); + /* + * Write to slave address, to request a measurement. + * According with the datasheet it should be with no data, but + * for systems with I2C bus drivers that do not allow zero + * length packets we write one dummy byte to allow sensor + * measurements on them. + */ + if (i2c_get_functionality(client->adapter) & + I2C_FUNC_SMBUS_QUICK) { + ret = i2c_master_send(client, tmp, 0); + } else { + tmp[0] = 0; + ret = i2c_master_send(client, tmp, 1); + } if (ret < 0) goto out; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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