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Commit 72f02715 authored by Alexander Sverdlin's avatar Alexander Sverdlin Committed by Wolfram Sang
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of: i2c: Add i2c-mux-idle-disconnect DT property to PCA954x mux driver 



Add i2c-mux-idle-disconnect device tree property to PCA954x mux driver. The new
property forces the multiplexer to disconnect child buses in idle state. This is
used, for example, when there are several multiplexers on the same bus and the
devices on the underlying buses might have same I2C addresses.

Signed-off-by: default avatarAlexander Sverdlin <alexander.sverdlin@nsn.com>
[wsa: added a newline]
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 67105c5a

Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt

+3 −0
Original line number Diff line number Diff line
@@ -16,6 +16,9 @@ Required Properties: 
Optional Properties:



  - reset-gpios: Reference to the GPIO connected to the reset input.

  - i2c-mux-idle-disconnect: Boolean; if defined, forces mux to disconnect all

    children in idle state. This is necessary for example, if there are several

    multiplexers on the bus and the devices behind them use same I2C addresses.





Example:

drivers/i2c/muxes/i2c-mux-pca954x.c

+10 −1
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <linux/i2c-mux.h>

#include <linux/i2c/pca954x.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/pm.h>

#include <linux/slab.h>
@@ -186,6 +187,8 @@ static int pca954x_probe(struct i2c_client *client, 
{

	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);

	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);

	struct device_node *of_node = client->dev.of_node;

	bool idle_disconnect_dt;

	struct gpio_desc *gpio;

	int num, force, class;

	struct pca954x *data;
@@ -217,8 +220,13 @@ static int pca954x_probe(struct i2c_client *client, 
	data->type = id->driver_data;

	data->last_chan = 0;		   /* force the first selection */



	idle_disconnect_dt = of_node &&

		of_property_read_bool(of_node, "i2c-mux-idle-disconnect");



	/* Now create an adapter for each channel */

	for (num = 0; num < chips[data->type].nchans; num++) {

		bool idle_disconnect_pd = false;



		force = 0;			  /* dynamic adap number */

		class = 0;			  /* no class by default */

		if (pdata) {
@@ -229,12 +237,13 @@ static int pca954x_probe(struct i2c_client *client, 
			} else

				/* discard unconfigured channels */

				break;

			idle_disconnect_pd = pdata->modes[num].deselect_on_exit;

		}



		data->virt_adaps[num] =

			i2c_add_mux_adapter(adap, &client->dev, client,

				force, num, class, pca954x_select_chan,

				(pdata && pdata->modes[num].deselect_on_exit)

				(idle_disconnect_pd || idle_disconnect_dt)

					? pca954x_deselect_mux : NULL);



		if (data->virt_adaps[num] == NULL) {