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SubjectRe: [PATCH] w1: add fast search for single slave bus
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On 2011-11-28, at 15:06, Hubert Feurstein wrote:

> This enables a much more efficient way of device searching. It uses the
> 1-wire read-rom operation which allows the direct reading of the slave
> address. BUT this works only with exactly one slave on the bus.
>
> Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
> ---
> drivers/w1/Kconfig | 8 ++++++++
> drivers/w1/w1.c | 11 +++++++++++
> 2 files changed, 19 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig
> index fd2c7bd..e5006bc 100644
> --- a/drivers/w1/Kconfig
> +++ b/drivers/w1/Kconfig
> @@ -25,6 +25,14 @@ config W1_CON
> 2. Userspace commands. Includes read/write and search/alarm search commands.
> 3. Replies to userspace commands.
>
> +config W1_FAST_SEARCH
> + bool "Fast search (single slave bus only!)"
> + ---help---
> + This enables a much more efficient way of device searching. It uses the
> + 1-wire read-rom operation which allows the direct reading of the slave
> + address. BUT this works only with exactly one slave on the bus.
> + If unsure, say 'N'.
> +
Not needed I think, see below...
> source drivers/w1/masters/Kconfig
> source drivers/w1/slaves/Kconfig
>
> diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
> index c374978..7c648ec 100644
> --- a/drivers/w1/w1.c
> +++ b/drivers/w1/w1.c
> @@ -892,6 +892,17 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb
> break;
> }
>
> +#ifdef CONFIG_W1_FAST_SEARCH
> + if (dev->max_slave_count == 1) {
> + w1_write_8(dev, W1_READ_ROM);
> +
> + if (w1_read_block(dev, (u8 *)&rn, 8) == 8 && rn)
> + cb(dev, rn);
> +
> + break;
> + }
> +#endif
> +
I would drop the CONFIG item and just add this "if" block to the search function
unconditionnaly. Unless I am missing something, it wouldn't hurt multi-slave setups...
> /* Start the search */
> w1_write_8(dev, search_type);
> for (i = 0; i < 64; ++i) {
> --
> 1.7.4.1
>
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