On Mon, Jan 23, 2023 at 10:33:05AM +0100, Sascha Hauer wrote:
> And here is the point where you have to request that the EEPROM is
> actually availabe to support the deep probe mechanism. Before reading
> the EEPROM add a call to:
>
> of_device_ensure_probed_by_alias("eeprom0");
>
> Nowadays the read-MAC-address-from-EEPROM thingy would likely be done
> using nvmem cells which would boil this code down to device tree changes
> only. If you're feeling brave you could change this, I won't insist on
> it though.
>
> Sascha
Hey Sascha,
I did some refactoring today based on your suggestions and now have this code:
rc = of_device_ensure_probed_by_alias("eeprom0");
if (rc < 0) {
pr_err("Unable to probe Novena EEPROM: %s\n", strerror(-rc));
return NULL;
}
rc = read_file_2("/dev/eeprom0", &read, &eeprom, max);
This gets me this bootup sequence:
of_platform_device_create: register device 21a8000.i2c@xxxxxxxxxx, io=0x021a8000
register_device: 21a8000.i2c@xxxxxxxxxx
probe-> 21a8000.i2c@xxxxxxxxxx
imx-iomuxv3 20e0000.pinctrl@xxxxxxxxxx: set state: /soc/bus@2000000/pinctrl@20e0000/i2c3grp-novena
__request_region ok: 0x021a8000:0x021abfff flags=0x0
of_get_named_gpio_flags: cannot parse sda-gpios property: -2
of_get_named_gpio_flags: cannot parse scl-gpios property: -2
<NULL>: <i2c_fsl_set_clk> I2C_CLK=66000000, REQ DIV=660
<NULL>: <i2c_fsl_set_clk> IFDR[IC]=0x39, REAL DIV=768
register_device: i2c0
register_device: es83280
es83280: registered on bus 0, chip->addr 0x11
register_device: 24c5120
probe-> 24c5120
of_get_named_gpio_flags: cannot parse wp-gpios property: -2
at24 24c5120: Registering nvmem device eeprom0
register_device: eeprom00
at24 24c5120: registered on bus 0, chip->addr 0x56
eeprom00: read ofs: 0x00000000 count: 0x00000014
i2c0: master_xfer[0] W, addr=0x56, len=2
i2c0: master_xfer[1] R, addr=0x56, len=20
i2c0: timeout waiting for status set 0x20, cur status: 0x93
at24 24c5120: read 20@0 --> -95 (1046280961)
Unable to read Novena EEPROM: Connection timed out
After the shell boots I'm able to read /dev/eeprom0 just fine.
John.
