[U-Boot] [PATCH v3 40/57] ram: rk3399: Update lpddr4 vref_mode_ac

Kever Yang
2019-07-16T13:17:17Z

On 2019/7/16 下午7:57, Jagan Teki wrote:
> Update vref_mode_ac for lpddr4 based on VDDQ/3/2=16.8%
>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> Signed-off-by: YouMin Chen <cym@rock-chips.com>

Reviewed-by: Kever Yang <Kever.yang@rock-chips.com>

Thanks,
- Kever
> ---
> drivers/ram/rockchip/sdram_rk3399.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/ram/rockchip/sdram_rk3399.c b/drivers/ram/rockchip/sdram_rk3399.c
> index 63763062f9..e3f1abf7e7 100644
> --- a/drivers/ram/rockchip/sdram_rk3399.c
> +++ b/drivers/ram/rockchip/sdram_rk3399.c
> @@ -366,7 +366,8 @@ static int phy_io_config(const struct chan_info *chan,
> vref_value_dq = (rd_vref - 15300) / 521;
> }
> vref_mode_ac = 0x6;
> - vref_value_ac = 0x1f;
> + /* VDDQ/3/2=16.8% */
> + vref_value_ac = 0x3;
> } else if (params->base.dramtype == LPDDR3) {
> if (params->base.odt == 1) {
> vref_mode_dq = 0x5; /* LPDDR3 ODT */