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drivers: w1: Make 1-Wire Skip ROM cmd. optional

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For systems with a true dynamic 1-Wire nature, the 1-Wire devices
cannot be defined in the DeviceTree (the number of slaves in
the system is not known during the build time).

In other words, there are no pre-defined 1-Wire devices on the bus in
DeviceTree, and thus the slave_count variable is always zero.

That means the skip_rom functionality will always be called even if
there are multiple devices connected to the bus.

This commit allows the user to override this original behavior and avoid
the skip_rom call by ignoring the slave count variable.

Also, this work preserves full backward compatibility.

Signed-off-by: Pavel Hübner <pavel.hubner@hardwario.com>
This commit is contained in:
Pavel Hübner 2023-04-04 08:02:09 +02:00 • committed by Carles Cufí
commit 83d031c024
2 changed files with 14 additions and 1 deletions
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13
drivers/w1/Kconfig
View file

@ -53,4 +53,17 @@ config W1_NET
help
Enable 1-wire network layer
config W1_NET_FORCE_MULTIDROP_ADDRESSING
bool "Force 1-Wire multidrop addressing"
depends on W1_NET
help
This option will ignore the number of 1-Wire
slave devices defined in the DTS. Specifically,
this option avoids the SKIP ROM command,
which is otherwise used in case of a single
1-Wire slave on the bus. In most cases, enabling
this option is not needed, yet it is essential
if multiple 1-Wire devices unspecified in the
DTS are interfaced.
endif # W1

2
drivers/w1/w1_net.c
View file

@ -346,7 +346,7 @@ int w1_skip_rom(const struct device *dev, const struct w1_slave_config *config)
static int reset_select(const struct device *dev, const struct w1_slave_config *config)
{
if (w1_get_slave_count(dev) > 1) {
if (IS_ENABLED(CONFIG_W1_NET_FORCE_MULTIDROP_ADDRESSING) || w1_get_slave_count(dev) > 1) {
return match_rom(dev, config);
}