[PATCH v10 2/7] i2c: mux: add idle_state property to i2c_mux_core
From: Marcus Folkesson <marcus.folkesson@gmail.com>
Date: 2026-07-08 12:17:00
Also in:
linux-i2c, lkml
Subsystem:
i2c muxes, i2c subsystem, the rest · Maintainers:
Peter Rosin, Andi Shyti, Linus Torvalds
Muxes treat their channels differently when idle. Let the mux core have this information to make it available for internal use. Reuse the same state values used by CONFIG_MULTIPLEXER. Possible idle states are: - MUX_IDLE_AS_IS: Leave channels as is when idle - MUX_IDLE_DISCONNECT: Disconnect channel (set HiZ when idle) - <n>: Enable channel n when idle Default value is set to MUX_IDLE_AS_IS. Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com> --- drivers/i2c/i2c-mux.c | 1 + include/linux/i2c-mux.h | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+)
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 681a201c239b..edf16683dc83 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c@@ -247,6 +247,7 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, muxc->select = select; muxc->deselect = deselect; muxc->max_adapters = max_adapters; + muxc->idle_state = MUX_IDLE_AS_IS; return muxc; }
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index 1784ac7afb11..624fadbaa703 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h@@ -13,6 +13,7 @@ #ifdef __KERNEL__ +#include <dt-bindings/mux/mux.h> #include <linux/bitops.h> struct i2c_mux_core {
@@ -22,6 +23,17 @@ struct i2c_mux_core { unsigned int arbitrator:1; unsigned int gate:1; + /* + * The mux controller state to use when inactive. + * Possible idle states are: + * - MUX_IDLE_AS_IS: Leave channels as is when idle + * - MUX_IDLE_DISCONNECT: Disconnect channel (set HiZ when idle) + * - <n>: Enable channel n when idle + * + * Default value is set to MUX_IDLE_AS_IS. + */ + int idle_state; + void *priv; int (*select)(struct i2c_mux_core *, u32 chan_id);
@@ -38,6 +50,20 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, int (*select)(struct i2c_mux_core *, u32), int (*deselect)(struct i2c_mux_core *, u32)); +/* + * Mux drivers may only change idle_state, and may only do so + * between allocation and registration of the mux controller. + */ +static inline void i2c_mux_set_idle_state(struct i2c_mux_core *muxc, int state) +{ + muxc->idle_state = state; +} + +static inline int i2c_mux_idle_state(struct i2c_mux_core *muxc) +{ + return muxc->idle_state; +} + /* flags for i2c_mux_alloc */ #define I2C_MUX_LOCKED BIT(0) #define I2C_MUX_ARBITRATOR BIT(1)
--
2.54.0