Re: [PATCH 1/8] regmap: Add generic non-memory mapped register access API

Ben Hutchings
2011-07-01T00:22:50Z

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On Wed, 2011-06-22 at 19:45 +0100, Mark Brown wrote:
[...]
> --- /dev/null
> +++ b/drivers/regmap/regmap.c
[...]
> +static void regmap_format_4_12_write(struct regmap *map,
> + unsigned int reg, unsigned int val)
> +{
> + u16 *out = map->work_buf;

__be16 *out

> + *out = cpu_to_be16((reg << 12) | val);
> +}
> +
> +static void regmap_format_7_9_write(struct regmap *map,
> + unsigned int reg, unsigned int val)
> +{
> + u16 *out = map->work_buf;

__be16 *out

> + *out = cpu_to_be16((reg << 9) | val);
> +}
> +
> +static void regmap_format_8(void *buf, unsigned int val)
> +{
> + u8 *b = buf;
> +
> + b[0] = val;
> +}
> +
> +static void regmap_format_16(void *buf, unsigned int val)
> +{
> + u16 *b = buf;

__be16 *b

> + b[0] = cpu_to_be16(val);
> +}
> +
> +static unsigned int regmap_parse_8(void *buf)
> +{
> + u8 *b = buf;
> +
> + return b[0];
> +}
> +
> +static unsigned int regmap_parse_16(void *buf)
> +{
> + u16 *b = buf;

__be16 *b

> + b[0] = be16_to_cpu(b[0]);
> +
> + return b[0];

The assignment doesn't seem to be necessary and will irritate sparse,
so:

return be16_to_cpu(b[0]);

> +}
> +
> +/**
> + * remap_init: Initialise register map

Missing 'g' in 'regmap_init'. And the first line's format must be:

regmap_init() - Initialise register map

(The other functions all have this problem as well.)

> + * dev: Device that will be interacted with
> + * config: Configuration for register map

Missing '@' before the parameter names.

[...]
> +static int _regmap_raw_write(struct regmap *map, unsigned int reg,
> + const void *val, size_t val_len)
> +{
> + void *buf;
> + int ret = -ENOTSUPP;
> + size_t len;
> +
> + map->format.format_reg(map->work_buf, reg);
> +
> + /* Try to do a gather write if we can */
> + if (map->bus->gather_write)
> + ret = map->bus->gather_write(map->dev, map->work_buf,
> + map->format.reg_bytes,
> + val, val_len);
> +
> + /* Otherwise fall back on linearising by hand. */
> + if (ret == -ENOTSUPP) {
> + len = map->format.reg_bytes + val_len;
> + buf = kmalloc(len, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> + memcpy(buf, map->work_buf, map->format.reg_bytes);
> + memcpy(buf + map->format.reg_bytes, val, val_len);
[...]

If I understand correctly, this is usually called by _regmap_write() and
val is already at the appropriate offset in work_buf. Is it not worth
avoiding the allocation in that case?

General comments:

- All the functions must be called in process context, but this isn't
documented.
- I think this could go in lib or drivers/base rather than in a new
directory. The specific support for I2C and SPI would go in their
existing directories.

Ben.

--
Ben Hutchings
If the facts do not conform to your theory, they must be disposed of.

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