[PATCH V2 4/4] imx: imx8mn-beacon: Fix out of spec voltage

[sbabic at denx.de]

> The DDR is configured for LPDDR4 running at 1.6GHz which requires
> the voltage on the PMIC to rise a bit before initializing LPDDR4
> or it will be running out of spec.
> Signed-off-by: Adam Ford <aford173 at gmail.com>
> Reviewed-by: Fabio Estevam <festevam at denx.de>
> Reviewed-by: Peng Fan <peng.fan at nxp.com>
> diff --git a/board/beacon/imx8mn/spl.c b/board/beacon/imx8mn/spl.c
> index 029f71bc99..9acd916180 100644
> --- a/board/beacon/imx8mn/spl.c
> +++ b/board/beacon/imx8mn/spl.c
> @@ -74,6 +74,38 @@ static iomux_v3_cfg_t const pwm_pads[] = {
>  	IMX8MN_PAD_GPIO1_IO01__PWM1_OUT | MUX_PAD_CTRL(PWM1_PAD_CTRL),
>  };
>  
> +static int power_init_board(void)
> +{
> +	struct udevice *dev;
> +	int ret;
> +
> +	ret = pmic_get("pmic at 4b", &dev);
> +	if (ret == -ENODEV) {
> +		puts("No pmic\n");
> +		return 0;
> +	}
> +
> +	if (ret != 0)
> +		return ret;
> +
> +	/* decrease RESET key long push time from the default 10s to 10ms */
> +	pmic_reg_write(dev, BD718XX_PWRONCONFIG1, 0x0);
> +
> +	/* unlock the PMIC regs */
> +	pmic_reg_write(dev, BD718XX_REGLOCK, 0x1);
> +
> +	/* increase VDD_SOC to typical value 0.85v before first DRAM access */
> +	pmic_reg_write(dev, BD718XX_BUCK1_VOLT_RUN, 0x0f);
> +
> +	/* increase VDD_DRAM to 0.975v for 3Ghz DDR */
> +	pmic_reg_write(dev, BD718XX_1ST_NODVS_BUCK_VOLT, 0x83);
> +
> +	/* lock the PMIC regs */
> +	pmic_reg_write(dev, BD718XX_REGLOCK, 0x11);
> +
> +	return 0;
> +}
> +
>  int board_early_init_f(void)
>  {
>  	/* Claiming pwm pins prevents LCD flicker during startup*/
> @@ -107,6 +139,9 @@ void board_init_f(ulong dummy)
>  
>  	enable_tzc380();
>  
> +	/* LPDDR4 at 1.6GHz requires a voltage adjustment on the PMIC */
> +	power_init_board();
> +
>  	/* DDR initialization */
>  	spl_dram_init();
>  
Applied to u-boot-imx, master, thanks !

Best regards,
Stefano Babic

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