[v2,2/2] i2c: mux: pca954x: add property idle-state

[Biwen Li]

This adds property idle-state

Signed-off-by: Biwen Li <biwen...@nxp.com>
---
Change in v2:
        - update subject and description
        - add property idle-state

 drivers/i2c/muxes/i2c-mux-pca954x.c | 47 ++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 17 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c 
b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 923aa3a5a3dc..8ec586342b92 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -86,7 +86,7 @@ struct pca954x {
 
        u8 last_chan;           /* last register value */
        /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
-       s8 idle_state;
+       s32 idle_state;
 
        struct i2c_client *client;
 
@@ -256,7 +256,7 @@ static int pca954x_deselect_mux(struct i2c_mux_core *muxc, 
u32 chan)
 {
        struct pca954x *data = i2c_mux_priv(muxc);
        struct i2c_client *client = data->client;
-       s8 idle_state;
+       s32 idle_state;
 
        idle_state = READ_ONCE(data->idle_state);
        if (idle_state >= 0)
@@ -402,6 +402,25 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc)
        i2c_mux_del_adapters(muxc);
 }
 
+static int pca954x_init(struct i2c_client *client, struct pca954x *data)
+{
+       /*
+        * Write the mux register at addr to verify
+        * that the mux is in fact present. This also
+        * initializes the mux to disconnected state.
+        */
+       if (data->idle_state >= 0) {
+               /* Always enable multiplexer */
+               if (data->chip->muxtype == pca954x_ismux)
+                       data->last_chan = data->idle_state | data->chip->enable;
+               else
+                       data->last_chan = 1 << data->idle_state;
+       } else {
+               /* Disconnect multiplexer */
+               data->last_chan = 0; /* force the first selection */
+       }
+       return i2c_smbus_write_byte(client, data->last_chan);
+}
 /*
  * I2C init/probing/exit functions
  */
@@ -411,7 +430,6 @@ static int pca954x_probe(struct i2c_client *client,
        struct i2c_adapter *adap = client->adapter;
        struct device *dev = &client->dev;
        struct device_node *np = dev->of_node;
-       bool idle_disconnect_dt;
        struct gpio_desc *gpio;
        struct i2c_mux_core *muxc;
        struct pca954x *data;
@@ -462,22 +480,18 @@ static int pca954x_probe(struct i2c_client *client,
                }
        }
 
-       /* Write the mux register at addr to verify
-        * that the mux is in fact present. This also
-        * initializes the mux to disconnected state.
-        */
-       if (i2c_smbus_write_byte(client, 0) < 0) {
+       if (of_property_read_u32(np, "idle-state", &data->idle_state))
+               data->idle_state = MUX_IDLE_AS_IS;
+
+       if (of_property_read_bool(np, "i2c-mux-idle-disconnect"))
+               data->idle_state = MUX_IDLE_DISCONNECT;
+
+       ret = pca954x_init(client, data);
+       if (ret < 0) {
                dev_warn(dev, "probe failed\n");
                return -ENODEV;
        }
 
-       data->last_chan = 0;               /* force the first selection */
-       data->idle_state = MUX_IDLE_AS_IS;
-
-       idle_disconnect_dt = np &&
-               of_property_read_bool(np, "i2c-mux-idle-disconnect");
-       if (idle_disconnect_dt)
-               data->idle_state = MUX_IDLE_DISCONNECT;
 
        ret = pca954x_irq_setup(muxc);
        if (ret)
@@ -531,8 +545,7 @@ static int pca954x_resume(struct device *dev)
        struct i2c_mux_core *muxc = i2c_get_clientdata(client);
        struct pca954x *data = i2c_mux_priv(muxc);
 
-       data->last_chan = 0;
-       return i2c_smbus_write_byte(client, 0);
+       return pca954x_init(client, data);
 }
 #endif
 
-- 
2.17.1