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Message-ID: <984d928a37b3db11ae53c07da672ccae0d79734f.camel@pengutronix.de>
Date: Fri, 06 Sep 2024 16:19:00 +0200
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Jerome Brunet <jbrunet@...libre.com>, Stephen Boyd <sboyd@...nel.org>,
Neil Armstrong <neil.armstrong@...aro.org>, Kevin Hilman
<khilman@...libre.com>, Martin Blumenstingl
<martin.blumenstingl@...glemail.com>, Jiucheng Xu <jiucheng.xu@...ogic.com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-amlogic@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/9] reset: amlogic: convert driver to regmap
On Fr, 2024-09-06 at 15:34 +0200, Jerome Brunet wrote:
> To allow using the same driver for the main reset controller and the
> auxiliary ones embedded in the clock controllers, convert the
> the Amlogic reset driver to regmap.
>
> Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>
> Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
> ---
> drivers/reset/reset-meson.c | 79 ++++++++++++++++++++++++---------------------
This patch should also make RESET_MESON select REGMAP.
> 1 file changed, 43 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/reset/reset-meson.c b/drivers/reset/reset-meson.c
> index 1e9fca3e30e8..9dd38cc209e2 100644
> --- a/drivers/reset/reset-meson.c
> +++ b/drivers/reset/reset-meson.c
> @@ -11,36 +11,43 @@
> #include <linux/of.h>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> +#include <linux/regmap.h>
> #include <linux/reset-controller.h>
> #include <linux/slab.h>
> #include <linux/types.h>
>
> -#define BITS_PER_REG 32
> -
> struct meson_reset_param {
> int reg_count;
> int level_offset;
> };
>
> struct meson_reset {
> - void __iomem *reg_base;
> const struct meson_reset_param *param;
> struct reset_controller_dev rcdev;
> - spinlock_t lock;
> + struct regmap *map;
> };
>
> +static void meson_reset_offset_and_bit(struct meson_reset *data,
> + unsigned long id,
> + unsigned int *offset,
> + unsigned int *bit)
> +{
> + unsigned int stride = regmap_get_reg_stride(data->map);
You know this is always 4. Having a #define for this (that is also used
to initialize regmap_config.reg_stride, and for now nr_resets, below)
instead of going through an exported function would allow the compiler
to optimize this all away:
> +
> + *offset = (id / (stride * BITS_PER_BYTE)) * stride;
> + *bit = id % (stride * BITS_PER_BYTE);
> +}
> +
> static int meson_reset_reset(struct reset_controller_dev *rcdev,
> - unsigned long id)
> + unsigned long id)
> {
> struct meson_reset *data =
> container_of(rcdev, struct meson_reset, rcdev);
> - unsigned int bank = id / BITS_PER_REG;
> - unsigned int offset = id % BITS_PER_REG;
> - void __iomem *reg_addr = data->reg_base + (bank << 2);
> + unsigned int offset, bit;
>
> - writel(BIT(offset), reg_addr);
> + meson_reset_offset_and_bit(data, id, &offset, &bit);
>
> - return 0;
> + return regmap_write(data->map, offset, BIT(bit));
> }
>
> static int meson_reset_level(struct reset_controller_dev *rcdev,
> @@ -48,25 +55,13 @@ static int meson_reset_level(struct reset_controller_dev *rcdev,
> {
> struct meson_reset *data =
> container_of(rcdev, struct meson_reset, rcdev);
> - unsigned int bank = id / BITS_PER_REG;
> - unsigned int offset = id % BITS_PER_REG;
> - void __iomem *reg_addr;
> - unsigned long flags;
> - u32 reg;
> + unsigned int offset, bit;
>
> - reg_addr = data->reg_base + data->param->level_offset + (bank << 2);
> + meson_reset_offset_and_bit(data, id, &offset, &bit);
> + offset += data->param->level_offset;
>
> - spin_lock_irqsave(&data->lock, flags);
> -
> - reg = readl(reg_addr);
> - if (assert)
> - writel(reg & ~BIT(offset), reg_addr);
> - else
> - writel(reg | BIT(offset), reg_addr);
> -
> - spin_unlock_irqrestore(&data->lock, flags);
> -
> - return 0;
> + return regmap_update_bits(data->map, offset,
> + BIT(bit), assert ? 0 : BIT(bit));
Matter of taste, perhaps, but the BIT() could be moved into
meson_reset_offset_and_bit().
> }
>
> static int meson_reset_assert(struct reset_controller_dev *rcdev,
> @@ -119,30 +114,42 @@ static const struct of_device_id meson_reset_dt_ids[] = {
> };
> MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
>
> +static const struct regmap_config regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> +};
> +
> static int meson_reset_probe(struct platform_device *pdev)
> {
> + struct device *dev = &pdev->dev;
> struct meson_reset *data;
> + void __iomem *base;
>
> - data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> if (!data)
> return -ENOMEM;
>
> - data->reg_base = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(data->reg_base))
> - return PTR_ERR(data->reg_base);
> + base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
>
> - data->param = of_device_get_match_data(&pdev->dev);
> + data->param = of_device_get_match_data(dev);
> if (!data->param)
> return -ENODEV;
>
> - spin_lock_init(&data->lock);
> + data->map = devm_regmap_init_mmio(dev, base, ®map_config);
> + if (IS_ERR(data->map))
> + return dev_err_probe(dev, PTR_ERR(data->map),
> + "can't init regmap mmio region\n");
>
> data->rcdev.owner = THIS_MODULE;
> - data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
> + data->rcdev.nr_resets = data->param->reg_count * BITS_PER_BYTE
> + * regmap_config.reg_stride;
> data->rcdev.ops = &meson_reset_ops;
> - data->rcdev.of_node = pdev->dev.of_node;
> + data->rcdev.of_node = dev->of_node;
>
> - return devm_reset_controller_register(&pdev->dev, &data->rcdev);
> + return devm_reset_controller_register(dev, &data->rcdev);
> }
>
> static struct platform_driver meson_reset_driver = {
regards
Philipp
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