i2c-mux-gpio: use reg value for i2c_add_mux_adapter

PATCH Applied Ionut Nicu 2 participants 2 messages Oct 11, 2013 – Oct 30, 2013

Subsystems (3)

I2C subsystem host drivers I2C muxes Generic GPIO I2C multiplexer driver

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Ionut Nicu

author

2013-10-11 10:09 UTC #0 lore raw

PATCH 2/2 i2c-mux-gpio: use reg value for i2c_add_mux_adapter

The i2c-mux driver requires that the chan_id parameter passed to the i2c_add_mux_adapter() function is equal to the reg value for that adapter:

for_each_child_of_node(mux_dev->of_node, child) {
	ret = of_property_read_u32(child, "reg", &reg);
	if (ret)
		continue;
	if (chan_id == reg) {
		priv->adap.dev.of_node = child;
		break;
	}
}

The i2c-mux-gpio driver uses an internal logical index for chan_id when calling i2c_add_mux_adapter() instead of using the reg value.

Because of this, there will problems in selecting the right adapter when the i2c-mux-gpio's index into mux->data.values doesn't match the reg value.

An example of such a case:

mux->data.values = { 1, 0 }

For chan_id = 0, i2c-mux will bind the adapter to the of_node with reg = <0>, but when it will call the select() callback with chan_id set to 0, the i2c-mux-gpio will use it as an index into mux->data.values and it will actually select the bus with reg = <1>.

Signed-off-by Ionut Nicu <[email protected]>

---
 drivers/i2c/muxes/i2c-mux-gpio.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

drivers/i2c/muxes/i2c-mux-gpio.c +2 -2

index 550e094..ed3e849 100644
@@ -38,7 +38,7 @@ static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
 {
 	struct gpiomux *mux = data;
 
-	i2c_mux_gpio_set(mux, mux->data.values[chan]);
+	i2c_mux_gpio_set(mux, chan);
 
 	return 0;
 }

@@ -228,7 +228,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
 
 		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
-						   i, class,
+						   mux->data.values[i], class,
 						   i2c_mux_gpio_select, deselect);
 		if (!mux->adap[i]) {
 			ret = -ENODEV;

Signature · 1 line

1.7.1

Wolfram Sang

Applied

2013-10-30 16:30 UTC #1 lore raw

Quoted 33 lines · Ionut Nicu

The i2c-mux driver requires that the chan_id parameter passed to the i2c_add_mux_adapter() function is equal to the reg value for that adapter:
for_each_child_of_node(mux_dev->of_node, child) {
	ret = of_property_read_u32(child, "reg", &reg);
	if (ret)
		continue;
	if (chan_id == reg) {
		priv->adap.dev.of_node = child;
		break;
	}
}
The i2c-mux-gpio driver uses an internal logical index for chan_id when calling i2c_add_mux_adapter() instead of using the reg value.
Because of this, there will problems in selecting the right adapter when the i2c-mux-gpio's index into mux->data.values doesn't match the reg value.
An example of such a case:
mux->data.values = { 1, 0 }
For chan_id = 0, i2c-mux will bind the adapter to the of_node with reg = <0>, but when it will call the select() callback with chan_id set to 0, the i2c-mux-gpio will use it as an index into mux->data.values and it will actually select the bus with reg = <1>.
Signed-off-by Ionut Nicu <[email protected]>

Quoted 8 lines · Ionut Nicu

Some gpio chips may have get/set operations that can sleep. gpio_set_value() only works for chips which do not sleep, for the others we will get a kernel warning. Using gpio_set_value_cansleep() will work for both chips that do sleep and those who don't.
Signed-off-by Ionut Nicu <[email protected]>

Applied to for-next, thanks! Added to stable, too. Also, please write the changes since last time. This really speeds up reviewing!