Re: [PATCH 3/6] pinctrl: sunxi: Support the 2.5V I/O bias mode

From: "Jernej Škrabec" <jernej.skrabec@gmail.com>
To: Chen-Yu Tsai <wens@csie.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Samuel Holland <samuel@sholland.org>
Cc: Samuel Holland <samuel@sholland.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Maxime Ripard <mripard@kernel.org>, Ondrej Jirman <x@xff.cz>,
	Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-sunxi@lists.linux.dev
Subject: Re: [PATCH 3/6] pinctrl: sunxi: Support the 2.5V I/O bias mode
Date: Mon, 27 Jun 2022 22:43:02 +0200	[thread overview]
Message-ID: <1818958.tdWV9SEqCh@jernej-laptop> (raw)
In-Reply-To: <20220626021148.56740-4-samuel@sholland.org>

Dne nedelja, 26. junij 2022 ob 04:11:44 CEST je Samuel Holland napisal(a):
> H616 and newer SoCs feature a 2.5V I/O bias mode in addition to the
> 1.8V and 3.3V modes. This mode is entered by selecting the 3.3V level
> and disabling the "withstand function".
> 
> H616 supports this capability on its main PIO only. A100 supports this
> capability on both its PIO and R-PIO.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
> 
>  drivers/pinctrl/sunxi/pinctrl-sun50i-a100-r.c |  1 +
>  drivers/pinctrl/sunxi/pinctrl-sun50i-a100.c   |  2 +-
>  drivers/pinctrl/sunxi/pinctrl-sun50i-h616.c   |  2 +-
>  drivers/pinctrl/sunxi/pinctrl-sunxi.c         | 10 ++++++++++
>  drivers/pinctrl/sunxi/pinctrl-sunxi.h         |  7 +++++++
>  5 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sun50i-a100-r.c
> b/drivers/pinctrl/sunxi/pinctrl-sun50i-a100-r.c index
> 21054fcacd34..afc1f5df7545 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sun50i-a100-r.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sun50i-a100-r.c
> @@ -82,6 +82,7 @@ static const struct sunxi_pinctrl_desc a100_r_pinctrl_data
> = { .npins = ARRAY_SIZE(a100_r_pins),
>  	.pin_base = PL_BASE,
>  	.irq_banks = 1,
> +	.io_bias_cfg_variant = BIAS_VOLTAGE_PIO_POW_MODE_CTL,
>  };
> 
>  static int a100_r_pinctrl_probe(struct platform_device *pdev)
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sun50i-a100.c
> b/drivers/pinctrl/sunxi/pinctrl-sun50i-a100.c index
> e69f6da40dc0..f682e0e4244d 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sun50i-a100.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sun50i-a100.c
> @@ -684,7 +684,7 @@ static const struct sunxi_pinctrl_desc a100_pinctrl_data
> = { .npins = ARRAY_SIZE(a100_pins),
>  	.irq_banks = 7,
>  	.irq_bank_map = a100_irq_bank_map,
> -	.io_bias_cfg_variant = BIAS_VOLTAGE_PIO_POW_MODE_SEL,
> +	.io_bias_cfg_variant = BIAS_VOLTAGE_PIO_POW_MODE_CTL,
>  };
> 
>  static int a100_pinctrl_probe(struct platform_device *pdev)
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sun50i-h616.c
> b/drivers/pinctrl/sunxi/pinctrl-sun50i-h616.c index
> 152b71226a80..d6ca720ee8d8 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sun50i-h616.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sun50i-h616.c
> @@ -525,7 +525,7 @@ static const struct sunxi_pinctrl_desc h616_pinctrl_data
> = { .irq_banks = ARRAY_SIZE(h616_irq_bank_map),
>  	.irq_bank_map = h616_irq_bank_map,
>  	.irq_read_needs_mux = true,
> -	.io_bias_cfg_variant = BIAS_VOLTAGE_PIO_POW_MODE_SEL,
> +	.io_bias_cfg_variant = BIAS_VOLTAGE_PIO_POW_MODE_CTL,
>  };
> 
>  static int h616_pinctrl_probe(struct platform_device *pdev)
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> b/drivers/pinctrl/sunxi/pinctrl-sunxi.c index 3c5e71359ca8..eb3d595f816a
> 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> @@ -662,6 +662,16 @@ static int sunxi_pinctrl_set_io_bias_cfg(struct
> sunxi_pinctrl *pctl, reg &= ~IO_BIAS_MASK;
>  		writel(reg | val, pctl->membase + 
sunxi_grp_config_reg(pin));
>  		return 0;
> +	case BIAS_VOLTAGE_PIO_POW_MODE_CTL:
> +		val = uV > 1800000 && uV <= 2500000 ? BIT(bank) : 0;
> +
> +		raw_spin_lock_irqsave(&pctl->lock, flags);
> +		reg = readl(pctl->membase + PIO_POW_MOD_CTL_REG);
> +		reg &= ~BIT(bank);
> +		writel(reg | val, pctl->membase + PIO_POW_MOD_CTL_REG);
> +		raw_spin_unlock_irqrestore(&pctl->lock, flags);
> +
> +		fallthrough;

Would this set bit 12 as needed? According to documentation, it's a bit 
special case, since it covers VCC-IO, port F and port H, at least according to 
documentation. I guess BIAS_VOLTAGE_PIO_POW_MODE_SEL has same issue.

Best regards,
Jernej

>  	case BIAS_VOLTAGE_PIO_POW_MODE_SEL:
>  		val = uV <= 1800000 ? 1 : 0;
> 
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> b/drivers/pinctrl/sunxi/pinctrl-sunxi.h index a32bb5bcb754..0f1aab58650c
> 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> @@ -98,6 +98,7 @@
>  #define PINCTRL_SUN8I_V3S	BIT(10)
> 
>  #define PIO_POW_MOD_SEL_REG	0x340
> +#define PIO_POW_MOD_CTL_REG	0x344
> 
>  enum sunxi_desc_bias_voltage {
>  	BIAS_VOLTAGE_NONE,
> @@ -111,6 +112,12 @@ enum sunxi_desc_bias_voltage {
>  	 * register, as seen on H6 SoC, for example.
>  	 */
>  	BIAS_VOLTAGE_PIO_POW_MODE_SEL,
> +	/*
> +	 * Bias voltage is set through PIO_POW_MOD_SEL_REG
> +	 * and PIO_POW_MOD_CTL_REG register, as seen on
> +	 * A100 and D1 SoC, for example.
> +	 */
> +	BIAS_VOLTAGE_PIO_POW_MODE_CTL,
>  };
> 
>  struct sunxi_desc_function {