On 05/12/14 22:52, Srinivas Pandruvada wrote: > This chip allows some limited number of sensors connected to it as > slaves, which can be directly accessed by register interface of this > driver.But the current upstream driver doesn't support such mode. > To attach such slaves to main processor i2c bus, chip has to be set > up in bypass mode. This change adds i2c mux, which will enable/disable > this mode for transaction to/from such slave devices. > This was discussed for a while in mailing list, this was the outcome: > Reference: > http://www.spinics.net/lists/linux-iio/msg12126.html > http://comments.gmane.org/gmane.linux.kernel.iio/11470 > > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> > Reviewed-by: Wolfram Sang <wsa@xxxxxxxxxxxxx> Applied to the togreg branch of IIO.git Thanks, > > --- > drivers/iio/imu/inv_mpu6050/Kconfig | 1 + > drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 115 +++++++++++++++++++++++++++-- > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 6 ++ > 3 files changed, 116 insertions(+), 6 deletions(-) > > diff --git a/drivers/iio/imu/inv_mpu6050/Kconfig b/drivers/iio/imu/inv_mpu6050/Kconfig > index 2d0608b..48fbc0b 100644 > --- a/drivers/iio/imu/inv_mpu6050/Kconfig > +++ b/drivers/iio/imu/inv_mpu6050/Kconfig > @@ -7,6 +7,7 @@ config INV_MPU6050_IIO > depends on I2C && SYSFS > select IIO_BUFFER > select IIO_TRIGGERED_BUFFER > + select I2C_MUX > help > This driver supports the Invensense MPU6050 devices. > This driver can also support MPU6500 in MPU6050 compatibility mode > diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > index b75519d..6d2c115 100644 > --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > @@ -23,6 +23,7 @@ > #include <linux/kfifo.h> > #include <linux/spinlock.h> > #include <linux/iio/iio.h> > +#include <linux/i2c-mux.h> > #include "inv_mpu_iio.h" > > /* > @@ -52,6 +53,7 @@ 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 = { > @@ -77,6 +79,83 @@ int inv_mpu6050_write_reg(struct inv_mpu6050_state *st, int reg, u8 d) > return i2c_smbus_write_i2c_block_data(st->client, reg, 1, &d); > } > > +/* > + * The i2c read/write needs to happen in unlocked mode. As the parent > + * adapter is common. If we use locked versions, it will fail as > + * the mux adapter will lock the parent i2c adapter, while calling > + * select/deselect functions. > + */ > +static int inv_mpu6050_write_reg_unlocked(struct inv_mpu6050_state *st, > + u8 reg, u8 d) > +{ > + int ret; > + u8 buf[2]; > + struct i2c_msg msg[1] = { > + { > + .addr = st->client->addr, > + .flags = 0, > + .len = sizeof(buf), > + .buf = buf, > + } > + }; > + > + buf[0] = reg; > + buf[1] = d; > + ret = __i2c_transfer(st->client->adapter, msg, 1); > + if (ret != 1) > + return ret; > + > + return 0; > +} > + > +static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv, > + u32 chan_id) > +{ > + struct iio_dev *indio_dev = mux_priv; > + struct inv_mpu6050_state *st = iio_priv(indio_dev); > + int ret = 0; > + > + /* Use the same mutex which was used everywhere to protect power-op */ > + mutex_lock(&indio_dev->mlock); > + if (!st->powerup_count) { > + ret = inv_mpu6050_write_reg_unlocked(st, st->reg->pwr_mgmt_1, > + 0); > + if (ret) > + goto write_error; > + > + msleep(INV_MPU6050_REG_UP_TIME); > + } > + if (!ret) { > + st->powerup_count++; > + ret = inv_mpu6050_write_reg_unlocked(st, st->reg->int_pin_cfg, > + st->client->irq | > + INV_MPU6050_BIT_BYPASS_EN); > + } > +write_error: > + mutex_unlock(&indio_dev->mlock); > + > + return ret; > +} > + > +static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap, > + void *mux_priv, u32 chan_id) > +{ > + struct iio_dev *indio_dev = mux_priv; > + struct inv_mpu6050_state *st = iio_priv(indio_dev); > + > + mutex_lock(&indio_dev->mlock); > + /* It doesn't really mattter, if any of the calls fails */ > + inv_mpu6050_write_reg_unlocked(st, st->reg->int_pin_cfg, > + st->client->irq); > + st->powerup_count--; > + if (!st->powerup_count) > + inv_mpu6050_write_reg_unlocked(st, st->reg->pwr_mgmt_1, > + INV_MPU6050_BIT_SLEEP); > + mutex_unlock(&indio_dev->mlock); > + > + return 0; > +} > + > int inv_mpu6050_switch_engine(struct inv_mpu6050_state *st, bool en, u32 mask) > { > u8 d, mgmt_1; > @@ -133,13 +212,22 @@ int inv_mpu6050_switch_engine(struct inv_mpu6050_state *st, bool en, u32 mask) > > int inv_mpu6050_set_power_itg(struct inv_mpu6050_state *st, bool power_on) > { > - int result; > + int result = 0; > + > + if (power_on) { > + /* Already under indio-dev->mlock mutex */ > + if (!st->powerup_count) > + result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1, > + 0); > + if (!result) > + st->powerup_count++; > + } else { > + st->powerup_count--; > + if (!st->powerup_count) > + result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1, > + INV_MPU6050_BIT_SLEEP); > + } > > - if (power_on) > - result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1, 0); > - else > - result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1, > - INV_MPU6050_BIT_SLEEP); > if (result) > return result; > > @@ -673,6 +761,7 @@ static int inv_mpu_probe(struct i2c_client *client, > > st = iio_priv(indio_dev); > st->client = client; > + st->powerup_count = 0; > pdata = dev_get_platdata(&client->dev); > if (pdata) > st->plat_data = *pdata; > @@ -720,8 +809,21 @@ static int inv_mpu_probe(struct i2c_client *client, > goto out_remove_trigger; > } > > + st->mux_adapter = i2c_add_mux_adapter(client->adapter, > + &client->dev, > + indio_dev, > + 0, 0, 0, > + inv_mpu6050_select_bypass, > + inv_mpu6050_deselect_bypass); > + if (!st->mux_adapter) { > + result = -ENODEV; > + goto out_unreg_device; > + } > + > return 0; > > +out_unreg_device: > + iio_device_unregister(indio_dev); > out_remove_trigger: > inv_mpu6050_remove_trigger(st); > out_unreg_ring: > @@ -734,6 +836,7 @@ static int inv_mpu_remove(struct i2c_client *client) > struct iio_dev *indio_dev = i2c_get_clientdata(client); > struct inv_mpu6050_state *st = iio_priv(indio_dev); > > + i2c_del_mux_adapter(st->mux_adapter); > iio_device_unregister(indio_dev); > inv_mpu6050_remove_trigger(st); > iio_triggered_buffer_cleanup(indio_dev); > diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h > index e779931..aa837de 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 */ > @@ -119,6 +120,8 @@ struct inv_mpu6050_state { > enum inv_devices chip_type; > spinlock_t time_stamp_lock; > struct i2c_client *client; > + struct i2c_adapter *mux_adapter; > + unsigned int powerup_count; > struct inv_mpu6050_platform_data plat_data; > DECLARE_KFIFO(timestamps, long long, TIMESTAMP_FIFO_SIZE); > }; > @@ -179,6 +182,9 @@ struct inv_mpu6050_state { > /* 6 + 6 round up and plus 8 */ > #define INV_MPU6050_OUTPUT_DATA_SIZE 24 > > +#define INV_MPU6050_REG_INT_PIN_CFG 0x37 > +#define INV_MPU6050_BIT_BYPASS_EN 0x2 > + > /* init parameters */ > #define INV_MPU6050_INIT_FIFO_RATE 50 > #define INV_MPU6050_TIME_STAMP_TOR 5 > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
