From 8eb5c87a92c065aaca39ac3e841b07906a4959a2 Mon Sep 17 00:00:00 2001 From: Dustin Byford Date: Fri, 23 Oct 2015 12:27:07 -0700 Subject: i2c: add ACPI support for I2C mux ports Although I2C mux devices are easily enumerated using ACPI (_HID/_CID or device property compatible string match), enumerating I2C client devices connected through an I2C mux needs a little extra work. This change implements a method for describing an I2C device hierarchy that includes mux devices by using an ACPI Device() for each mux channel along with an _ADR to set the channel number for the device. See Documentation/acpi/i2c-muxes.txt for a simple example. To make this work the ismt, i801, and designware pci/platform devs now share an ACPI companion with their I2C adapter dev similar to how it's done in OF. This is done on the assumption that power management functions will not be called directly on the I2C dev that is sharing the ACPI node. Acked-by: Mika Westerberg Tested-by: Mika Westerberg Signed-off-by: Dustin Byford Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-mux.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/i2c/i2c-mux.c') diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 2ba7c0fbc615..00fc5b1c7b66 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -25,6 +25,7 @@ #include #include #include +#include /* multiplexer per channel data */ struct i2c_mux_priv { @@ -173,6 +174,13 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, } } + /* + * Associate the mux channel with an ACPI node. + */ + if (has_acpi_companion(mux_dev)) + acpi_preset_companion(&priv->adap.dev, ACPI_COMPANION(mux_dev), + chan_id); + if (force_nr) { priv->adap.nr = force_nr; ret = i2c_add_numbered_adapter(&priv->adap); -- cgit v1.2.3