On 03/15/2014 09:01 AM, Jonathan Cameron wrote:
On 11/03/14 21:04, Srinivas Pandruvada wrote:
This chip has two modes to control secondary sensor attached to it.
One is master mode and another is bypass mode. In master mode
MPU6500 will directly communicates to the secondary sensor device
attached to it. This can support very few secondary devices in this
mode.
But when configured in bypass mode the i2c lines are directly connected
to host i2c bus controller.
Since in master mode it can only support few devices and they are not
implemented in this driver, set the default mode to bypass mode.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
This has been proposed before by Manuel Stahl,
Please read the thread from
http://www.spinics.net/lists/linux-iio/msg11985.html
In short, the best way we have come up with for handling this cleanly
(avoiding issues with the device in between going into sleep etc) was
to implement an i2c bus multiplexer with 1 input and 1 output as part of
the driver.
Manuel, any progress on your patches?
I think the mux is the right solution for using master mode of MPU60X0.
But I feel that when this driver is initialized then we should disable
the master mode at init
as currently it doesn't have any implementation for slave devices as
Invensense typically do for Android devices.
Once a client want to use multiplexer then it can be turned on.
Invensense engineer (author of this driver) recommends not to use master
mode.
So my patch disables at init. I am calling this function from init. I
can remove export of symbol.
What do you think about this?
Thanks,
Srinivas
Jonathan
---
drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 20 +++++++++++++++++++-
drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 4 ++++
2 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index 4a76697..6ba565a 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -61,6 +61,7 @@ static const struct inv_mpu6050_reg_map
reg_set_6050 = {
.int_enable = INV_MPU6050_REG_INT_ENABLE,
.pwr_mgmt_1 = INV_MPU6050_REG_PWR_MGMT_1,
.pwr_mgmt_2 = INV_MPU6050_REG_PWR_MGMT_2,
+ .int_pin_cfg = INV_MPU6050_REG_INT_PIN_CFG,
};
static const struct inv_mpu6050_chip_config chip_config_6050 = {
@@ -616,6 +617,21 @@ static const struct iio_info mpu_info = {
.validate_trigger = inv_mpu6050_validate_trigger,
};
+int inv_set_bypass_status(struct inv_mpu6050_state *st, bool enable)
+{
+ int ret;
+
+ if (enable)
+ ret = inv_mpu6050_write_reg(st, st->reg->int_pin_cfg,
+ st->client->irq |
+ INV_MPU6050_BIT_BYPASS_EN);
+ else
+ ret = inv_mpu6050_write_reg(st, st->reg->int_pin_cfg,
+ st->client->irq);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(inv_set_bypass_status);
+
/**
* inv_check_and_setup_chip() - check and setup chip.
*/
@@ -654,7 +670,9 @@ static int inv_check_and_setup_chip(struct
inv_mpu6050_state *st,
if (result)
return result;
- return 0;
+ result = inv_set_bypass_status(st, true);
+
+ return result;
}
/**
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index f383955..de5aa22 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -54,6 +54,7 @@ struct inv_mpu6050_reg_map {
u8 int_enable;
u8 pwr_mgmt_1;
u8 pwr_mgmt_2;
+ u8 int_pin_cfg;
};
/*device enum */
@@ -185,6 +186,9 @@ struct inv_mpu6050_state {
#define INV_MPU6050_MIN_FIFO_RATE 4
#define INV_MPU6050_ONE_K_HZ 1000
+#define INV_MPU6050_REG_INT_PIN_CFG 0x37
+#define INV_MPU6050_BIT_BYPASS_EN 0x2
+
/* scan element definition */
enum inv_mpu6050_scan {
INV_MPU6050_SCAN_ACCL_X,
--
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