Subject: [PATCH 2/2] ARM: imx: add anatop settings for LPDDR2 when enter DSM mode

From: [email-masked] (Shawn Guo)
Date: Wed, 17 Sep 2014 10:25:06 +0800

On Mon, Sep 15, 2014 at 03:44:46PM +0800, Anson Huang wrote:
> For LPDDR2 platform, no need to enable weak2P5 in DSM mode,
> it can be pulled down to save power(~0.65mW).
> 
> And per design team's recommendation, we should disconnect
> VDDHIGH and SNVS in DSM mode on i.MX6SL.
> 
> Signed-off-by: Anson Huang <[email-masked]>
> ---
>  arch/arm/mach-imx/anatop.c |   36 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 34 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/anatop.c b/arch/arm/mach-imx/anatop.c
> index 8259a62..3b25b32 100644
> --- a/arch/arm/mach-imx/anatop.c
> +++ b/arch/arm/mach-imx/anatop.c
> @@ -30,11 +30,16 @@
>  #define ANADIG_DIGPROG_IMX6SL	0x280
>  
>  #define BM_ANADIG_REG_2P5_ENABLE_WEAK_LINREG	0x40000
> +#define BM_ANADIG_REG_2P5_ENABLE_PULLDOWN	0x8
>  #define BM_ANADIG_REG_CORE_FET_ODRIVE		0x20000000
>  #define BM_ANADIG_ANA_MISC0_STOP_MODE_CONFIG	0x1000
> +/* Below MISC0_DISCON_HIGH_SNVS is only for i.MX6SL */
> +#define BM_ANADIG_ANA_MISC0_DISCON_HIGH_SNVS	0x2000
>  #define BM_ANADIG_USB_CHRG_DETECT_CHK_CHRG_B	0x80000
>  #define BM_ANADIG_USB_CHRG_DETECT_EN_B		0x100000
>  
> +#define DDR_TYPE_LPDDR2		1

These two patches look good to me.  The only thing I think we may need
to improve is that this DDR_TYPE_LPDDR2 should be defined in a common
place, so that you do not need to define it twice, here and
suspend-imx6.S.

Shawn

> +
>  static struct regmap *anatop;
>  
>  static void imx_anatop_enable_weak2p5(bool enable)
> @@ -56,16 +61,43 @@ static void imx_anatop_enable_fet_odrive(bool enable)
>  		BM_ANADIG_REG_CORE_FET_ODRIVE);
>  }
>  
> +static inline void imx_anatop_enable_2p5_pulldown(bool enable)
> +{
> +	regmap_write(anatop, ANADIG_REG_2P5 + (enable ? REG_SET : REG_CLR),
> +		BM_ANADIG_REG_2P5_ENABLE_PULLDOWN);
> +}
> +
> +static inline void imx_anatop_disconnect_high_snvs(bool enable)
> +{
> +	regmap_write(anatop, ANADIG_ANA_MISC0 + (enable ? REG_SET : REG_CLR),
> +		BM_ANADIG_ANA_MISC0_DISCON_HIGH_SNVS);
> +}
> +
>  void imx_anatop_pre_suspend(void)
>  {
> -	imx_anatop_enable_weak2p5(true);
> +	if (imx_mmdc_get_ddr_type() == DDR_TYPE_LPDDR2)
> +		imx_anatop_enable_2p5_pulldown(true);
> +	else
> +		imx_anatop_enable_weak2p5(true);
> +
>  	imx_anatop_enable_fet_odrive(true);
> +
> +	if (cpu_is_imx6sl())
> +		imx_anatop_disconnect_high_snvs(true);
>  }
>  
>  void imx_anatop_post_resume(void)
>  {
> +	if (imx_mmdc_get_ddr_type() == DDR_TYPE_LPDDR2)
> +		imx_anatop_enable_2p5_pulldown(false);
> +	else
> +		imx_anatop_enable_weak2p5(false);
> +
>  	imx_anatop_enable_fet_odrive(false);
> -	imx_anatop_enable_weak2p5(false);
> +
> +	if (cpu_is_imx6sl())
> +		imx_anatop_disconnect_high_snvs(false);
> +
>  }
>  
>  static void imx_anatop_usb_chrg_detect_disable(void)
> -- 
> 1.7.9.5
>