On Wed, Jan 11, 2023 at 09:01:14AM +0100, Ahmad Fatoum wrote:
> Now that we use regmap for the KSZ9477 driver, we can make the register
> map available for introspection as a device file. As the KSZ driver has
> a separate regmap for each of the three access sizes, we add a new
> regmap_multi_register_cdev abstraction that multiplexes device file
> access to the regmap with the best matching alignment.
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> drivers/base/regmap/Makefile | 1 +
> drivers/base/regmap/regmap-multi.c | 81 ++++++++++++++++++++++++++++++
> drivers/net/ksz9477.c | 6 ++-
> include/regmap.h | 2 +
> 4 files changed, 89 insertions(+), 1 deletion(-)
> create mode 100644 drivers/base/regmap/regmap-multi.c
>
> diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
> index d99db4277149..fe5beaaaa382 100644
> --- a/drivers/base/regmap/Makefile
> +++ b/drivers/base/regmap/Makefile
> @@ -1,5 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0-only
> obj-y += regmap.o
> +obj-y += regmap-multi.o
> obj-y += regmap-mmio.o
> obj-$(CONFIG_REGMAP_FORMATTED) += regmap-fmt.o
> obj-$(CONFIG_I2C) += regmap-i2c.o
> diff --git a/drivers/base/regmap/regmap-multi.c b/drivers/base/regmap/regmap-multi.c
> new file mode 100644
> index 000000000000..79dd1ba9bd95
> --- /dev/null
> +++ b/drivers/base/regmap/regmap-multi.c
> @@ -0,0 +1,81 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2022 Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> + */
> +
> +#include <common.h>
> +#include <regmap.h>
> +#include <linux/export.h>
> +
> +#include "internal.h"
> +
> +enum { MULTI_MAP_8, MULTI_MAP_16, MULTI_MAP_32, MULTI_MAP_COUNT };
> +struct regmap_multi {
> + struct cdev cdev;
> + struct regmap *map[MULTI_MAP_COUNT];
> +};
> +
> +static struct regmap *regmap_multi_cdev_get_map(struct cdev *cdev, size_t count)
> +{
> + struct regmap_multi *multi = container_of(cdev, struct regmap_multi, cdev);
> + struct regmap *map = NULL;
> +
> + if (count % 4 == 0)
> + map = multi->map[MULTI_MAP_32];
> + if (!map && count % 2 == 0)
> + map = multi->map[MULTI_MAP_16];
> + return map ?: multi->map[MULTI_MAP_8];
> +}
You pick the regmap only based on 'count'. Shouldn't you take the offset
into account as well?
> +
> +static ssize_t regmap_multi_cdev_read(struct cdev *cdev, void *buf, size_t count,
> + loff_t offset, unsigned long flags)
> +{
> + struct regmap *map = regmap_multi_cdev_get_map(cdev, count);
> +
> + return regmap_bulk_read(map, offset, buf, count) ?: count;
> +}
> +
> +static ssize_t regmap_multi_cdev_write(struct cdev *cdev, const void *buf, size_t count,
> + loff_t offset, unsigned long flags)
> +{
> + struct regmap *map = regmap_multi_cdev_get_map(cdev, count);
> +
> + return regmap_bulk_write(map, offset, buf, count) ?: count;
> +}
> +
> +static struct cdev_operations regmap_multi_fops = {
> + .read = regmap_multi_cdev_read,
> + .write = regmap_multi_cdev_write,
> +};
> +
> +int regmap_multi_register_cdev(struct regmap *maps[3])
MULTI_MAP_COUNT instead of 3?
Sascha
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