I am trying to interface freescale imx6 SoC with mpu92/65 sensor device. I have taken mpu92/65 device driver from android (https://github.com/NoelMacwan/Kernel-10.4.1.B.0.101/tree/master/drivers/staging/iio/imu ) and have done necessary modifications to the driver and device tree.
Device tree modifications:
&i2c3{
...
extaccelerometer: mpu9250@68{
compatible = "mpu9250";
reg = <0x68>;
interrupt-parent = <&gpio2>;
interrupts = <9>;
int_config = /bits/ 8 <0x00>;
level_shifter = /bits/ 8 <0>;
orientation = [ 01 00 00 00 01 00 00 00 01 ];
sec_slave_type = <2>;
sec_slave_id = <0x12>;
secondary_i2c_addr = /bits/ 16 <0x0C>;
secondary_orientation = [ 00 01 00 ff 00 00 00 00 01 ];
};
}
inv_mpu_iio driver modifications:
static void get_platdata(struct device *dev, struct inv_mpu_iio_s *st){
struct device_node *np = dev->of_node;
int i=0;
of_property_read_u8(np, "int_config", &st->plat_data.int_config);
of_property_read_u8(np, "level_shifter", &st->plat_data.level_shifter);
of_property_read_u8_array(np, "orientation", &st->plat_data.orientation,9);
of_property_read_u32(np, "sec_slave_type", &st->plat_data.sec_slave_type);
of_property_read_u32(np, "sec_slave_id", &st->plat_data.sec_slave_id);
of_property_read_u16(np, "secondary_i2c_addr", &st->plat_data.secondary_i2c_addr);
of_property_read_u8_array(np, "secondary_orientation", &st->plat_data.secondary_orientation,9);
}
static int inv_mpu_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
.....
if (client->dev.of_node) {
get_platdata(&client->dev, st);
} else {
st->plat_data = *(struct mpu_platform_data *)dev_get_platdata(&client->dev);
}
.....
}
I have retrieved the platform data from device tree in the above manner. In probe function I am getting client->irq=0
. But I have mentioned about the IRQ in the device tree. Please can someone tell me what else I need to do to mention gpio2-9 (linux pad) as an interrupt line for this i2c device.
0x68 is the slave address of the i2c device. Driver probe functionality is trying to write on to the device for verifying the chip type initially. So the data and the address of the slave is sent to the adapter driver where in the adapter driver start function writes onto and reads from control and status registers is successfully executed.
static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
{
unsigned int temp = 0;
int result;
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
i2c_imx_set_clk(i2c_imx);
result = clk_prepare_enable(i2c_imx->clk);
if (result)
return result;
imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR,__func__);
/* Enable I2C controller */
imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR,__func__);
imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode, i2c_imx, IMX_I2C_I2CR,__func__);
/* Wait controller to be stable */
udelay(50);
/* Start I2C transaction */
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
temp |= I2CR_MSTA;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR,__func__);
result = i2c_imx_bus_busy(i2c_imx, 1);
if (result)
return result;
i2c_imx->stopped = 0;
temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
temp &= ~I2CR_DMAEN;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR,__func__);
return result;
}
Then the adapter driver writes on to the data register
imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR,__func__);
After this the adapter interrupt is generated ( bus interrupt got i2c3: 291).
static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
{
struct imx_i2c_struct *i2c_imx = dev_id;
unsigned int temp;
printk("irq:%d\n",irq);
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
if (temp & I2SR_IIF) {
/* save status register */
i2c_imx->i2csr = temp;
temp &= ~I2SR_IIF;
printk("temp=%d\n",temp);
temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR,__func__);
wake_up(&i2c_imx->queue);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
In ISR after reading status register the value should be 162
(last bit should be 0
to indicate acknowledged) but for my device I am getting this value as 163
(last bit is 1 so it is not acknowledged). Then in acknowledge success function -EIO
error is thrown. For all the other device connected to this bus the status register after writing onto the data register is 162
.
I don't know why I am getting the above behavior. And one more thing is that even if I don't connect the device the start function is able to write into and read from the status and control registers. I am not sure which status register is being read and writing into. If I assume that this writes and reads the adapter registers, then can I also assume that the adapter h/w automatically reads and writes onto the device connected. If so then how am I getting the same behavior if I don't connect the device?
Please help me out.
of_match_table
is. Have you populated and assigned it? See this and this commits for example. Once it's done yourclient->irq
will be populated automatically. – Sam Protsenko.id_table
and.of_match_table
must be defined and assigned in I2C driver struct. See my answer below. – Sam Protsenko