linux-kernel - Re: [PATCH V2 02/12] pinctrl: tegra: add suspend and resume support

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Message-ID: <6273a790-d4b7-c501-3fec-d9816288b139@gmail.com>
Date:   Wed, 29 May 2019 18:29:52 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Sowjanya Komatineni <skomatineni@...dia.com>,
        thierry.reding@...il.com, jonathanh@...dia.com, tglx@...utronix.de,
        jason@...edaemon.net, marc.zyngier@....com,
        linus.walleij@...aro.org, stefan@...er.ch, mark.rutland@....com
Cc:     pdeschrijver@...dia.com, pgaikwad@...dia.com, sboyd@...nel.org,
        linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
        jckuo@...dia.com, josephl@...dia.com, talho@...dia.com,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
        mperttunen@...dia.com, spatra@...dia.com, robh+dt@...nel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH V2 02/12] pinctrl: tegra: add suspend and resume support

29.05.2019 2:08, Sowjanya Komatineni пишет:
> This patch adds suspend and resume support for Tegra pinctrl driver
> and registers them to syscore so the pinmux settings are restored
> before the devices resume.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
> ---
>  drivers/pinctrl/tegra/pinctrl-tegra.c    | 68 +++++++++++++++++++++++++++++++-
>  drivers/pinctrl/tegra/pinctrl-tegra.h    |  3 ++
>  drivers/pinctrl/tegra/pinctrl-tegra114.c |  1 +
>  drivers/pinctrl/tegra/pinctrl-tegra124.c |  1 +
>  drivers/pinctrl/tegra/pinctrl-tegra20.c  |  1 +
>  drivers/pinctrl/tegra/pinctrl-tegra210.c |  1 +
>  drivers/pinctrl/tegra/pinctrl-tegra30.c  |  1 +
>  7 files changed, 75 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/tegra/pinctrl-tegra.c b/drivers/pinctrl/tegra/pinctrl-tegra.c
> index a5008c066bac..bdc47e62c457 100644
> --- a/drivers/pinctrl/tegra/pinctrl-tegra.c
> +++ b/drivers/pinctrl/tegra/pinctrl-tegra.c
> @@ -28,11 +28,18 @@
>  #include <linux/pinctrl/pinmux.h>
>  #include <linux/pinctrl/pinconf.h>
>  #include <linux/slab.h>
> +#include <linux/syscore_ops.h>
>  
>  #include "../core.h"
>  #include "../pinctrl-utils.h"
>  #include "pinctrl-tegra.h"
>  
> +#define EMMC2_PAD_CFGPADCTRL_0			0x1c8
> +#define EMMC4_PAD_CFGPADCTRL_0			0x1e0
> +#define EMMC_DPD_PARKING			(0x1fff << 14)
> +
> +static struct tegra_pmx *pmx;
> +
>  static inline u32 pmx_readl(struct tegra_pmx *pmx, u32 bank, u32 reg)
>  {
>  	return readl(pmx->regs[bank] + reg);
> @@ -629,6 +636,50 @@ static void tegra_pinctrl_clear_parked_bits(struct tegra_pmx *pmx)
>  	}
>  }
>  
> +static int __maybe_unused tegra_pinctrl_suspend(void)
> +{
> +	u32 *backup_regs = pmx->backup_regs;
> +	u32 *regs;
> +	int i, j;
> +
> +	for (i = 0; i < pmx->nbanks; i++) {
> +		regs = pmx->regs[i];
> +		for (j = 0; j < pmx->reg_bank_size[i] / 4; j++)
> +			*backup_regs++ = readl(regs++);
> +	}
> +
> +	return pinctrl_force_sleep(pmx->pctl);
> +}
> +
> +static void __maybe_unused tegra_pinctrl_resume(void)
> +{
> +	u32 *backup_regs = pmx->backup_regs;
> +	u32 *regs;
> +	u32 val;
> +	int i, j;
> +
> +	for (i = 0; i < pmx->nbanks; i++) {
> +		regs = pmx->regs[i];
> +		for (j = 0; j < pmx->reg_bank_size[i] / 4; j++)
> +			writel(*backup_regs++, regs++);
> +	}
> +
> +	if (pmx->soc->has_park_padcfg) {
> +		val = pmx_readl(pmx, 0, EMMC2_PAD_CFGPADCTRL_0);
> +		val &= ~EMMC_DPD_PARKING;
> +		pmx_writel(pmx, val, 0, EMMC2_PAD_CFGPADCTRL_0);
> +
> +		val = pmx_readl(pmx, 0, EMMC4_PAD_CFGPADCTRL_0);
> +		val &= ~EMMC_DPD_PARKING;
> +		pmx_writel(pmx, val, 0, EMMC4_PAD_CFGPADCTRL_0);
> +	}
> +}
>

But the CFGPADCTRL registers are already programmed by restoring the
backup_regs and hence the relevant EMMC's are already unparked. Hence
why do you need to force-unpark both of the EMMC's? What if EMMC is
unpopulated on a board, why do you need to unpark it then?

-- 
Dmitry