[PATCH v3] ARM: imx: verdin-imx8mm: Set CAN oscillator frequency based on model

[Marek Vasut]

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: Martyn Welch <martyn.welch at collabora.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: u-boot at lists.denx.de
---
V2: - Update the comment in conditional statement
    - Update ver_assembly check for 0055 rev.A/B/C/D
V3: - Update code comment per upstream feedback
---
 board/toradex/verdin-imx8mm/verdin-imx8mm.c | 29 +++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/board/toradex/verdin-imx8mm/verdin-imx8mm.c b/board/toradex/verdin-imx8mm/verdin-imx8mm.c
index 55c02653da6..59cc28f652f 100644
--- a/board/toradex/verdin-imx8mm/verdin-imx8mm.c
+++ b/board/toradex/verdin-imx8mm/verdin-imx8mm.c
@@ -125,6 +125,35 @@ 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 following "prodid" (PID4 in Toradex naming) use
+	 * a 20MHz CAN oscillator:
+	 * - 0055, V1.1A, V1.1B, V1.1C and V1.1D
+	 * - 0059, V1.1A and V1.1B
+	 */
+	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) ||	/* 0059 rev. A or B */
+	     (tdx_hw_tag.prodid == VERDIN_IMX8MMQ_WIFI_BT_IT &&
+	      tdx_hw_tag.ver_assembly <= 3))) {	/* 0055 rev. A/B/C/D */
+		freq = 20000000;
+	}
+
+	ret = fdt_setprop_u32(blob, canoscoff, "clock-frequency", freq);
+	if (ret < 0) {
+		printf("Failed to set CAN oscillator clock-frequency, ret=%d\n",
+		       ret);
+	}
+
+exit:
 	return ft_common_board_setup(blob, bd);
 }
 #endif
-- 
2.43.0