Gregory,
Thank you for your answer.
I think I'm asking very easy question since I'm very new to NuttX.
I'm not still sure how I can enable an I2C device.
I understood that there are lower-half driver and upper-half driver and
they should be associated each other with initialization code.
Refering some documents like below, I added some lines to do that.
I can see /dev/i2c1 now but i2c tool still does not detect any i2c device.
https://github.com/apache/incubator-nuttx/blob/master/boards/arm/stm32f0l0g0/nucleo-g070rb/src/stm32_bringup.c#L89-L111
I also tried to make upper-half driver refering here.
https://github.com/micro-ROS/NuttX/issues/9
In this case, I call mpu9250_register() which I made instead of
i2c_register().
/dev/i2c1 appeared with ls /dev.
However, `i2c dev -b 1 0x03 0x77 ` did not detect any i2c device.
Yuta Ide
On 2021/04/30 22:18, Gregory Nutt wrote:
On 4/30/2021 6:34 AM, yuta wrote:
Hi all,
I'm trying to use I2C.
I configured below in menuconfig.
- System Type > STM32 Peripheral Support > [*] I2C1
- Device Drivers > [*] I2C Driver Support
then compilation was done successfully.
But no I2C device( like /dev/i2c1 ) showed up when I tried ls /dev
Do I forget something to do?
I'm using Nucleo-F767ZI board.
Thank you.
Yuta Ide
Did you enable an I2C device? STM32 I2C peripheral support is not an
I2C device. It an I2C "lower half" and will not create a character
device. You also have to (1) enable an "upper half" device that uses
I2C, (2) create an instance of the I2C "lower half", and (3) bind the
"lower half" to the "upper half" and register the driver.
Remember, I2C is not a device. I2C is a bus that provides the
physical transport to devices on the bus. You should not normally do
direct bus access from applications .. although you can with
drivers/i2c/i2c_driver.c. i2c_driver.c can be used by your
board-initialization logic to create a character device that will
allow appliations to access the bus directly. So you can create some
kind of very limited user-space driver. It is limited because it
cannot integrate simply with other aspects of the device such as GPIO
controls or interrupts.
