netdev - Re: [PATCH 10/12] pinctrl: sunxi: Support I/O bias voltage setting on H6

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Message-ID: <20190408074222.ksyxorajs6goowmf@flea>
Date:   Mon, 8 Apr 2019 09:42:22 +0200
From:   Maxime Ripard <maxime.ripard@...tlin.com>
To:     megous@...ous.com
Cc:     linux-sunxi@...glegroups.com, Chen-Yu Tsai <wens@...e.org>,
        Rob Herring <robh+dt@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Mark Rutland <mark.rutland@....com>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S. Miller" <davem@...emloft.net>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Arend van Spriel <arend.vanspriel@...adcom.com>,
        Franky Lin <franky.lin@...adcom.com>,
        Hante Meuleman <hante.meuleman@...adcom.com>,
        Chi-Hsien Lin <chi-hsien.lin@...ress.com>,
        Wright Feng <wright.feng@...ress.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        Naveen Gupta <naveen.gupta@...ress.com>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com,
        linux-wireless@...r.kernel.org,
        brcm80211-dev-list.pdl@...adcom.com,
        brcm80211-dev-list@...ress.com, linux-gpio@...r.kernel.org
Subject: Re: [PATCH 10/12] pinctrl: sunxi: Support I/O bias voltage setting
 on H6

On Sat, Apr 06, 2019 at 01:45:12AM +0200, megous@...ous.com wrote:
> From: Ondrej Jirman <megous@...ous.com>
>
> H6 SoC has a "pio group withstand voltage mode" register (datasheet
> description), that needs to be used to select either 1.8V or 3.3V
> I/O mode, based on what voltage is powering the respective pin
> banks and is thus used for I/O signals.
>
> Add support for configuring this register according to the voltage
> of the pin bank regulator (if enabled).
>
> This is similar to the support for I/O bias voltage setting patch
> for A80 and the same concerns apply. (see commit 402bfb3c135213dc
> Support I/O bias voltage setting on A80).
>
> Signed-off-by: Ondrej Jirman <megous@...ous.com>
> ---
>  drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c |  1 +
>  drivers/pinctrl/sunxi/pinctrl-sunxi.c     | 14 ++++++++++++++
>  drivers/pinctrl/sunxi/pinctrl-sunxi.h     |  3 +++
>  3 files changed, 18 insertions(+)
>
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c b/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c
> index ef4268cc6227..30b1befa8ed8 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sun50i-h6.c
> @@ -591,6 +591,7 @@ static const struct sunxi_pinctrl_desc h6_pinctrl_data = {
>  	.irq_banks = 4,
>  	.irq_bank_map = h6_irq_bank_map,
>  	.irq_read_needs_mux = true,
> +	.io_bias_cfg_variant = IO_BIAS_CFG_V2,
>  };
>
>  static int h6_pinctrl_probe(struct platform_device *pdev)
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> index 9f329fec77cf..59a4ed396d92 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> @@ -607,6 +607,8 @@ static int sunxi_pinctrl_set_io_bias_cfg(struct sunxi_pinctrl *pctl,
>  					 unsigned pin,
>  					 struct regulator *supply)
>  {
> +	unsigned short bank = pin / PINS_PER_BANK;
> +	unsigned long flags;
>  	u32 val, reg;
>  	int uV;
>
> @@ -639,6 +641,18 @@ static int sunxi_pinctrl_set_io_bias_cfg(struct sunxi_pinctrl *pctl,
>  		reg = readl(pctl->membase + sunxi_grp_config_reg(pin));
>  		reg &= ~IO_BIAS_MASK;
>  		writel(reg | val, pctl->membase + sunxi_grp_config_reg(pin));
> +	} else if (pctl->desc->io_bias_cfg_variant == IO_BIAS_CFG_V2) {
> +		val = uV <= 1800000 ? 1 : 0;
> +
> +		dev_info(pctl->dev,
> +			 "Setting voltage bias to %sV on bank P%c\n",
> +			 val ? "1.8" : "3.3", 'A' + bank);
> +
> +		raw_spin_lock_irqsave(&pctl->lock, flags);
> +		reg = readl(pctl->membase + PIO_POW_MOD_SEL_REG);
> +		reg &= ~(1 << bank);
> +		writel(reg | val << bank, pctl->membase + PIO_POW_MOD_SEL_REG);
> +		raw_spin_unlock_irqrestore(&pctl->lock, flags);
>  	}
>
>  	return 0;
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> index 476772f91dba..3a66376f141b 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> @@ -95,7 +95,10 @@
>  #define PINCTRL_SUN7I_A20	BIT(7)
>  #define PINCTRL_SUN8I_R40	BIT(8)
>
> +#define PIO_POW_MOD_SEL_REG	0x340
> +
>  #define IO_BIAS_CFG_V1		1
> +#define IO_BIAS_CFG_V2		2

Can you document what V1 and V2 means exactly?

Thanks!
Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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