[RFC][PATCH] ARM: imx: verdin-imx8mm: Set CAN oscillator frequency based on model

[Marek Vasut]

On 1/15/24 16:44, Francesco Dolcini wrote:
> On Sat, Jan 13, 2024 at 07:33:17PM +0100, Marek Vasut wrote:
>> The older i.MX8M Mini Verdin SoMs before rev. 1.1C came with 20 MHz SPI CAN
>> controller oscillator, the newer SoMs use 40 MHz oscillator. Handle both by
>> overriding the oscillator frequency just before booting the kernel.
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> ---
>> Cc: "NXP i.MX U-Boot Team" <uboot-imx at nxp.com>
>> Cc: Fabio Estevam <festevam at gmail.com>
>> Cc: Francesco Dolcini <francesco.dolcini at toradex.com>
>> Cc: Marcel Ziswiler <marcel.ziswiler at toradex.com>
>> Cc: Philippe Schenker <philippe.schenker at toradex.com>
> 
> Philippe is no longer in toradex, removed from cc list.
> 
>> Cc: Stefano Babic <sbabic at denx.de>
>> ---
>>   board/toradex/verdin-imx8mm/verdin-imx8mm.c | 19 +++++++++++++++++++
>>   1 file changed, 19 insertions(+)
>>
>> diff --git a/board/toradex/verdin-imx8mm/verdin-imx8mm.c b/board/toradex/verdin-imx8mm/verdin-imx8mm.c
>> index b2781b51d6a..8bc1a51eeb1 100644
>> --- a/board/toradex/verdin-imx8mm/verdin-imx8mm.c
>> +++ b/board/toradex/verdin-imx8mm/verdin-imx8mm.c
>> @@ -142,6 +142,25 @@ int board_phys_sdram_size(phys_size_t *size)
>>   #if defined(CONFIG_OF_LIBFDT) && defined(CONFIG_OF_BOARD_SETUP)
>>   int ft_board_setup(void *blob, struct bd_info *bd)
>>   {
>> +	const char *canoscpath = "/oscillator";
>> +	int canoscoff, freq, ret;
>> +
>> +	canoscoff = fdt_path_offset(blob, canoscpath);
>> +	if (canoscoff < 0)	/* No CAN oscillator found. */
>> +		goto exit;
>> +
>> +	if (tdx_hw_tag.ver_assembly < 2)        /* rev. A or B */
>> +		freq = 20000000;
>> +	else					/* rev. C or newer */
>> +		freq = 40000000;
> 
> So, the situation is more complex than what I thought initially.
> 
> The actual frequency of the oscillator depends on the whole
> `struct toradex_hw`, you would need to check prodid, ver_major,
> ver_minor and ver_assembly.
> 	
> In addition to that code should not expect `ver_assembly` to be an
> increasing number, this is just a number that is matching the BOM.
> 
> The actual `prodid` (PID4 in Toradex naming) that have the CAN
> functionality are 0055 and 0059.
> 
> 0059, V1.1A and V1.1B, use a 20MHz oscillator
> 0055, V1.1A, V1.1B, V1.1C and V1.1D, use a 20Mhz oscillator

Do you happen to have a table of what was populated with which 
oscillator, so I can fill all the 20 MHz parts in right away ?