This chip has a mode in which this chipset can be i2c master. But
the current upstream driver doesn't support such mode as there is
some limited support of clients, which can be connected.
To attach such clients to main i2c bus chip has to be set up in
bypass mode. Creates an i2c mux, which will enable/disable this mode.
This was discussed for a while in mailing list, this was the decision.
This change also provides an API, which allows clients to be created for
this mux adapter.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
---
drivers/iio/imu/inv_mpu6050/Kconfig | 1 +
drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 163 +++++++++++++++++++++++++++--
drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 9 ++
3 files changed, 167 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..9864362 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 = {
@@ -72,11 +74,147 @@ static const struct inv_mpu6050_hw hw_info[INV_NUM_PARTS] = {
},
};
+static struct i2c_adapter *inv_mux_adapter;
+
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,
+ int 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)
+ 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);
+ }
+ 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;
+}
+
+static int inv_mpu6050_create_mux(struct iio_dev *indio_dev)
+{
+ struct inv_mpu6050_state *mpu_st = iio_priv(indio_dev);
+ struct i2c_client *client = mpu_st->client;
+
+ mpu_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 (mpu_st->mux_adapter == NULL) {
+ dev_err(&mpu_st->client->dev, "Mux create Failed\n");
+ return -ENODEV;
+ }
+ inv_mux_adapter = mpu_st->mux_adapter;
+
+ return 0;
+}
+
+static void inv_mpu6050_destroy_mux(struct iio_dev *indio_dev)
+{
+ struct inv_mpu6050_state *mpu_st = iio_priv(indio_dev);
+
+ if (mpu_st->mux_adapter)
+ i2c_del_mux_adapter(mpu_st->mux_adapter);
+ inv_mux_adapter = NULL;
+}
+
+struct i2c_client *inv_mpu6050_add_mux_client(char *name, int addr,
+ int irq, void *plat_data)
+{
+ struct i2c_client *client;
+ struct i2c_board_info info;
+
+ if (!inv_mux_adapter)
+ return NULL;
+
+ memset(&info, 0, sizeof(struct i2c_board_info));
+ strlcpy(info.type, name, sizeof(info.type));
+ info.addr = addr;
+ info.irq = irq;
+ info.platform_data = plat_data;
+ client = i2c_new_device(inv_mux_adapter, &info);
+ if (!client) {
+ dev_err(&inv_mux_adapter->dev,
+ "failed to create mux clint %d\n", addr);
+ return NULL;
+ }
+
+ return client;
+}
+EXPORT_SYMBOL_GPL(inv_mpu6050_add_mux_client);
+
+void inv_mpu6050_del_mux_client(struct i2c_client *client)
+{
+ i2c_unregister_device(client);
+}
+EXPORT_SYMBOL_GPL(inv_mpu6050_del_mux_client);
+
int inv_mpu6050_switch_engine(struct inv_mpu6050_state *st, bool en, u32 mask)
{
u8 d, mgmt_1;
@@ -133,13 +271,22 @@ 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 +820,7 @@ 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;
@@ -720,6 +868,8 @@ static int inv_mpu_probe(struct i2c_client *client,
goto out_remove_trigger;
}
+ inv_mpu6050_create_mux(indio_dev);
+
return 0;
out_remove_trigger:
@@ -734,6 +884,7 @@ 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);
+ inv_mpu6050_destroy_mux(indio_dev);
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..90697c6 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;
+ 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
@@ -245,3 +251,6 @@ int inv_reset_fifo(struct iio_dev *indio_dev);
int inv_mpu6050_switch_engine(struct inv_mpu6050_state *st, bool en, u32 mask);
int inv_mpu6050_write_reg(struct inv_mpu6050_state *st, int reg, u8 val);
int inv_mpu6050_set_power_itg(struct inv_mpu6050_state *st, bool power_on);
+struct i2c_client *inv_mpu6050_add_mux_client(char *name, int adddr,
+ int irq, void *plat_data);
+void inv_mpu6050_del_mux_client(struct i2c_client *client);
--
1.9.3
--
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