From 72f0271576eeef40c81c2949e0a8abeaef9a7690 Mon Sep 17 00:00:00 2001
From: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Date: Fri, 23 Jan 2015 16:41:29 +0100
Subject: [PATCH] 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: Alexander Sverdlin <alexander.sverdlin@nsn.com>
[wsa: added a newline]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
.../devicetree/bindings/i2c/i2c-mux-pca954x.txt | 3 +++
drivers/i2c/muxes/i2c-mux-pca954x.c | 11 ++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt
index 34a3fb6f8488b2..cf53d5fba20a09 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt
@@ -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:
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index ec11b404b43373..3d8f4fe2e47e52 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -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) {
--
GitLab