Merge branch 'i2c-mux/for-next' of https://github.com/peda-r/i2c-mux into i2c/for-5.6

The main feature is the idle-state rework of the pca954x driver from Biwen Li.

2 files changed, 61 insertions, 37 deletions

diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
index 50e1fb4aedf5..6daec8d3d331 100644
--- a/drivers/i2c/muxes/i2c-mux-pca9541.c
+++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
@@ -16,6 +16,7 @@
  * warranty of any kind, whether express or implied.
  */
 
+#include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/i2c.h>
@@ -42,20 +43,20 @@
 #define PCA9541_CONTROL		0x01
 #define PCA9541_ISTAT		0x02
 
-#define PCA9541_CTL_MYBUS	(1 << 0)
-#define PCA9541_CTL_NMYBUS	(1 << 1)
-#define PCA9541_CTL_BUSON	(1 << 2)
-#define PCA9541_CTL_NBUSON	(1 << 3)
-#define PCA9541_CTL_BUSINIT	(1 << 4)
-#define PCA9541_CTL_TESTON	(1 << 6)
-#define PCA9541_CTL_NTESTON	(1 << 7)
-
-#define PCA9541_ISTAT_INTIN	(1 << 0)
-#define PCA9541_ISTAT_BUSINIT	(1 << 1)
-#define PCA9541_ISTAT_BUSOK	(1 << 2)
-#define PCA9541_ISTAT_BUSLOST	(1 << 3)
-#define PCA9541_ISTAT_MYTEST	(1 << 6)
-#define PCA9541_ISTAT_NMYTEST	(1 << 7)
+#define PCA9541_CTL_MYBUS	BIT(0)
+#define PCA9541_CTL_NMYBUS	BIT(1)
+#define PCA9541_CTL_BUSON	BIT(2)
+#define PCA9541_CTL_NBUSON	BIT(3)
+#define PCA9541_CTL_BUSINIT	BIT(4)
+#define PCA9541_CTL_TESTON	BIT(6)
+#define PCA9541_CTL_NTESTON	BIT(7)
+
+#define PCA9541_ISTAT_INTIN	BIT(0)
+#define PCA9541_ISTAT_BUSINIT	BIT(1)
+#define PCA9541_ISTAT_BUSOK	BIT(2)
+#define PCA9541_ISTAT_BUSLOST	BIT(3)
+#define PCA9541_ISTAT_MYTEST	BIT(6)
+#define PCA9541_ISTAT_NMYTEST	BIT(7)
 
 #define BUSON		(PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
 #define MYBUS		(PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 923aa3a5a3dc..a0d926ae3f86 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;
 
@@ -229,20 +229,23 @@ static int pca954x_reg_write(struct i2c_adapter *adap,
 				I2C_SMBUS_BYTE, &dummy);
 }
 
+static u8 pca954x_regval(struct pca954x *data, u8 chan)
+{
+	/* We make switches look like muxes, not sure how to be smarter. */
+	if (data->chip->muxtype == pca954x_ismux)
+		return chan | data->chip->enable;
+	else
+		return 1 << chan;
+}
+
 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
 	struct pca954x *data = i2c_mux_priv(muxc);
 	struct i2c_client *client = data->client;
-	const struct chip_desc *chip = data->chip;
 	u8 regval;
 	int ret = 0;
 
-	/* we make switches look like muxes, not sure how to be smarter */
-	if (chip->muxtype == pca954x_ismux)
-		regval = chan | chip->enable;
-	else
-		regval = 1 << chan;
-
+	regval = pca954x_regval(data, chan);
 	/* Only select the channel if its different from the last channel */
 	if (data->last_chan != regval) {
 		ret = pca954x_reg_write(muxc->parent, client, regval);
@@ -256,7 +259,7 @@ 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 +405,22 @@ 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)
+{
+	int ret;
+
+	if (data->idle_state >= 0)
+		data->last_chan = pca954x_regval(data, data->idle_state);
+	else
+		data->last_chan = 0; /* Disconnect multiplexer */
+
+	ret = i2c_smbus_write_byte(client, data->last_chan);
+	if (ret < 0)
+		data->last_chan = 0;
+
+	return ret;
+}
+
 /*
  * 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;
@@ -462,23 +480,24 @@ static int pca954x_probe(struct i2c_client *client,
 		}
 	}
 
-	/* Write the mux register at addr to verify
+	data->idle_state = MUX_IDLE_AS_IS;
+	if (of_property_read_u32(np, "idle-state", &data->idle_state)) {
+		if (np && of_property_read_bool(np, "i2c-mux-idle-disconnect"))
+			data->idle_state = MUX_IDLE_DISCONNECT;
+	}
+
+	/*
+	 * Write the mux register at addr to verify
 	 * that the mux is in fact present. This also
-	 * initializes the mux to disconnected state.
+	 * initializes the mux to a channel
+	 * or disconnected state.
 	 */
-	if (i2c_smbus_write_byte(client, 0) < 0) {
+	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)
 		goto fail_cleanup;
@@ -530,9 +549,13 @@ static int pca954x_resume(struct device *dev)
 	struct i2c_client *client = to_i2c_client(dev);
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 	struct pca954x *data = i2c_mux_priv(muxc);
+	int ret;
 
-	data->last_chan = 0;
-	return i2c_smbus_write_byte(client, 0);
+	ret = pca954x_init(client, data);
+	if (ret < 0)
+		dev_err(&client->dev, "failed to verify mux presence\n");
+
+	return ret;
 }
 #endif