nvmem: imx-ocotp: add support for post processing

Add .cell_post_process callback for imx-ocotp to deal with MAC address,
since MAC address need to be reversed byte for some i.MX SoCs.

Tested-by: Joakim Zhang <[e-mail]>
Signed-off-by: Srinivas Kandagatla <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/nvmem/imx-ocotp.c

···
 	unsigned int bank_address_words;
 	void (*set_timing)(struct ocotp_priv *priv);
 	struct ocotp_ctrl_reg ctrl;
+	bool reverse_mac_address;
 };
 
 static int imx_ocotp_wait_for_busy(struct ocotp_priv *priv, u32 flags)
···
 	kfree(p);
 
 	return ret;
+}
+
+static int imx_ocotp_cell_pp(void *context, const char *id, unsigned int offset,
+			     void *data, size_t bytes)
+{
+	struct ocotp_priv *priv = context;
+
+	/* Deal with some post processing of nvmem cell data */
+	if (id && !strcmp(id, "mac-address")) {
+		if (priv->params->reverse_mac_address) {
+			u8 *buf = data;
+			int i;
+
+			for (i = 0; i < bytes/2; i++)
+				swap(buf[i], buf[bytes - i - 1]);
+		}
+	}
+
+	return 0;
 }
 
 static void imx_ocotp_set_imx6_timing(struct ocotp_priv *priv)
···
 	.stride = 1,
 	.reg_read = imx_ocotp_read,
 	.reg_write = imx_ocotp_write,
+	.cell_post_process = imx_ocotp_cell_pp,
 };
 
 static const struct ocotp_params imx6q_params = {
···
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
+	.reverse_mac_address = true,
 };
 
 static const struct ocotp_params imx8mm_params = {
···
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
+	.reverse_mac_address = true,
 };
 
 static const struct ocotp_params imx8mn_params = {
···
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_DEFAULT,
+	.reverse_mac_address = true,
 };
 
 static const struct ocotp_params imx8mp_params = {
···
 	.bank_address_words = 0,
 	.set_timing = imx_ocotp_set_imx6_timing,
 	.ctrl = IMX_OCOTP_BM_CTRL_8MP,
+	.reverse_mac_address = true,
 };
 
 static const struct of_device_id imx_ocotp_dt_ids[] = {