linux-kernel - Re: [RFC PATCH 1/3] reset: Add support for the Amlogic Meson GXBB Reset Controller

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Date:	Sat, 14 May 2016 17:07:02 +0200
From:	Kevin Hilman <khilman@...libre.com>
To:	Neil Armstrong <narmstrong@...libre.com>
Cc:	linux-kernel@...r.kernel.org, p.zabel@...gutronix.de,
	linux-arm-kernel@...ts.infradead.org,
	linux-amlogic@...ts.infradead.org
Subject: Re: [RFC PATCH 1/3] reset: Add support for the Amlogic Meson GXBB Reset Controller

Neil Armstrong <narmstrong@...libre.com> writes:

> This patch adds the platform driver for the Amlogic Meson GXBB Reset
> Controller.
>
> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>

[...]

> +static int meson_gxbb_reset_assert(struct reset_controller_dev *rcdev,
> +			      unsigned long id)
> +{
> +	struct meson_gxbb_reset *data =
> +		container_of(rcdev, struct meson_gxbb_reset, rcdev);
> +	unsigned int bank = id / BITS_PER_REG;
> +	unsigned int offset = id % BITS_PER_REG;
> +	void *reg_addr = data->reg_base + (bank << 2);
> +
> +	if (bank >= REG_COUNT)
> +		return -EINVAL;
> +
> +	writel(readl(reg_addr) | BIT(offset), reg_addr);

The spec lists these registers as 16-bit registers, so probably readw/writew
are more appropriate here.

> +	return 0;
> +}
> +
> +static int meson_gxbb_reset_deassert(struct reset_controller_dev *rcdev,
> +				unsigned long id)
> +{
> +	struct meson_gxbb_reset *data =
> +		container_of(rcdev, struct meson_gxbb_reset, rcdev);
> +	unsigned int bank = id / BITS_PER_REG;
> +	unsigned int offset = id % BITS_PER_REG;
> +	void *reg_addr = data->reg_base + (bank << 2);
> +
> +	if (bank >= REG_COUNT)
> +		return -EINVAL;
> +
> +	writel(readl(reg_addr) & ~BIT(offset), reg_addr);

and here.

> +	return 0;
> +}

Kevin