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

[Francesco Dolcini]

Hello Marek,
thanks for this.


On Tue, May 21, 2024 at 11:39:05AM +0200, Marek Vasut wrote:
> The older i.MX8M Mini Verdin SoMs may came with 20 MHz SPI CAN controller
> oscillator, the newer SoMs always use 40 MHz oscillator. Handle both by
> overriding the oscillator frequency just before booting the kernel.
> 
> These are the known variants with 20 MHz oscillator:
> - 0055, V1.1A, V1.1B, V1.1C and V1.1D, use a 20MHz oscillator
> - 0059, V1.1A and V1.1B, use a 20MHz oscillator
> 
> 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>
> Cc: Martyn Welch <martyn.welch at collabora.com>
> Cc: Stefano Babic <sbabic at denx.de>
> Cc: u-boot at lists.denx.de
> ---
>  board/toradex/verdin-imx8mm/verdin-imx8mm.c | 30 +++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/board/toradex/verdin-imx8mm/verdin-imx8mm.c b/board/toradex/verdin-imx8mm/verdin-imx8mm.c
> index 55c02653da6..b4a443ebfb0 100644
> --- a/board/toradex/verdin-imx8mm/verdin-imx8mm.c
> +++ b/board/toradex/verdin-imx8mm/verdin-imx8mm.c
> @@ -125,6 +125,36 @@ 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 freq = 40000000;	/* 40 MHz is used on most variants */
> +	int canoscoff, ret;
> +
> +	canoscoff = fdt_path_offset(blob, canoscpath);
> +	if (canoscoff < 0)	/* No CAN oscillator found. */
> +		goto exit;
> +
> +	/*
> +	 * The actual "prodid" (PID4 in Toradex naming) that have the CAN
> +	 * functionality are 0055 and 0059.
This is nor correct, we have more, they just always use 40MHz.

I would rephrase this:

/*
 * 20MHz CAN oscillator product variants:
 * - 0055, V1.1A, V1.1B, V1.1C and V1.1D
 * - 0059, V1.1A and V1.1B
 */

or in a different way, if you prefer, but you got the point.

> +	if ((tdx_hw_tag.ver_major == 1 && tdx_hw_tag.ver_minor == 1) &&
> +	    ((tdx_hw_tag.prodid == VERDIN_IMX8MMQ_IT &&
> +	      tdx_hw_tag.ver_assembly <= 1) ||	/* 0055 rev. A or B */
> +	     (tdx_hw_tag.prodid == VERDIN_IMX8MMQ_WIFI_BT_IT &&
> +	      tdx_hw_tag.ver_assembly <= 4))) {	/* 0059 rev. A/B/C/D */

ver_assembly is the hardware revision - 'A', e.g. 'A' is 0, 'D' is 3.

VERDIN_IMX8MMQ_IT is 0059
VERDIN_IMX8MMQ_WIFI_BT_IT is 0055

with that said, it should be

	if ((tdx_hw_tag.ver_major == 1 && tdx_hw_tag.ver_minor == 1) &&
	    ((tdx_hw_tag.prodid == VERDIN_IMX8MMQ_WIFI_BT_IT &&
	      tdx_hw_tag.ver_assembly <= 1) ||	/* 0055 rev. A or B */
	     (tdx_hw_tag.prodid == VERDIN_IMX8MMQ_IT &&
	      tdx_hw_tag.ver_assembly <= 3))) {	/* 0059 rev. A/B/C/D */


Francesco