boot init code depending on i2c eeprom value

Sascha Hauer s.hauer at pengutronix.de
Fri Aug 3 09:21:50 EDT 2012


On Fri, Aug 03, 2012 at 10:06:28AM +0200, christian.buettner at rafi.de wrote:
> Hi all,
> 
> i need to set the pin-mux of the board init code depending on an ID coming 
> from 
> an i2C EEPROM of the board.
> Is it possible to do something like this:
> 
> 
> ...
> 
> //Using the e.g. the postcore_initcall phase to init i2C
> static int
> ecuv6_postcore_init(void)
> {
>         //Set I2C EEPROM (24C32R) PIN MUX
>         mxc_iomux_v3_setup_multiple_pads(i2c_eeprom_pads, 
> ARRAY_SIZE(i2c_eeprom_pads));
>         imx53_add_i2c2(NULL);
>         return 0;
> }
> postcore_initcall(ecuv6_postcore_init);
> 
> //In the console_initcall phase, i2C should be probed to read ID
> static int
> ecuv6_console_init(void)
> {
>         imx53_init_lowlevel(0);
>         ecuv6_set_system_serial();
>  
>         //get_bb_pcb_number reads data from 
>         char bb_ID;
>         bb_ID = get_i2c_ID();
> 
>         //Set Pinmux depending on i2C result
>         if(bb_ID = 0xAB) {
>                 mxc_iomux_v3_setup_multiple_pads(AB_pads, ARRAY_SIZE(
> AB_pads));
>         }
>         else if(bb_ID = 0xCD) {
>                 mxc_iomux_v3_setup_multiple_pads(CD_pads, ARRAY_SIZE(
> CD_pads));
>         }
>  
>         imx53_add_uart0();
> 
>         return 0;
> }
> console_initcall(ecuv6_console_init);
> 
> ...
> 
> 
> Actually this is not working. The i2c_imx:i2c_imx_probe(..) function gets 
> called later.
> Is there a way or concept to do something like this?

You must call get_i2c_ID after registering the i2c device. you can call
mxc_iomux_v3_setup_multiple_pads multiple times, i.e. once for the UART
pins in console_init and once later when you know what hardware you
have.
This of cause does not work when your console pins depend on the
hardware version, in this case you must register your console in a
device_initcall later.

Sascha

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