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Commit eee543e8 authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
Browse files

i2c-mux: Add support for device auto-detection 



Let I2C bus segments behind multiplexers have a class. This allows for
device auto-detection on these segments. As long as parent segments
don't share the same class, it should be fine.

I implemented support in drivers i2c-mux-gpio and i2c-mux-pca954x. I
left i2c-mux-pca9541 and i2c-mux-pinctrl alone for the moment as I
don't know if this feature makes sense for the use cases of these
drivers.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
Cc: Peter Korsgaard <peter.korsgaard@barco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
Cc: Rodolfo Giometti <giometti@linux.it>
parent 5f3d2f2e

drivers/i2c/i2c-mux.c

+22 −0
Original line number Diff line number Diff line
@@ -88,9 +88,23 @@ static u32 i2c_mux_functionality(struct i2c_adapter *adap) 
	return parent->algo->functionality(parent);

}



/* Return all parent classes, merged */

static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)

{

	unsigned int class = 0;



	do {

		class |= parent->class;

		parent = i2c_parent_is_i2c_adapter(parent);

	} while (parent);



	return class;

}



struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,

				struct device *mux_dev,

				void *mux_priv, u32 force_nr, u32 chan_id,

				unsigned int class,

				int (*select) (struct i2c_adapter *,

					       void *, u32),

				int (*deselect) (struct i2c_adapter *,
@@ -127,6 +141,14 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, 
	priv->adap.algo_data = priv;

	priv->adap.dev.parent = &parent->dev;



	/* Sanity check on class */

	if (i2c_mux_parent_classes(parent) & class)

		dev_err(&parent->dev,

			"Segment %d behind mux can't share classes with ancestors\n",

			chan_id);

	else

		priv->adap.class = class;



	/*

	 * Try to populate the mux adapter's of_node, expands to

	 * nothing if !CONFIG_OF.

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

+3 −1
Original line number Diff line number Diff line
@@ -104,8 +104,10 @@ static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev) 


	for (i = 0; i < pdata->n_values; i++) {

		u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;

		unsigned int class = pdata->classes ? pdata->classes[i] : 0;



		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, i,

		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,

						   i, class,

						   i2c_mux_gpio_select, deselect);

		if (!mux->adap[i]) {

			ret = -ENODEV;

drivers/i2c/muxes/i2c-mux-pca9541.c

+1 −1
Original line number Diff line number Diff line
@@ -354,7 +354,7 @@ static int pca9541_probe(struct i2c_client *client, 
	if (pdata)

		force = pdata->modes[0].adap_id;

	data->mux_adap = i2c_add_mux_adapter(adap, &client->dev, client,

					     force, 0,

					     force, 0, 0,

					     pca9541_select_chan,

					     pca9541_release_chan);

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

+6 −4
Original line number Diff line number Diff line
@@ -186,7 +186,7 @@ static int pca954x_probe(struct i2c_client *client, 
{

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

	struct pca954x_platform_data *pdata = client->dev.platform_data;

	int num, force;

	int num, force, class;

	struct pca954x *data;

	int ret = -ENODEV;
@@ -216,18 +216,20 @@ static int pca954x_probe(struct i2c_client *client, 
	/* Now create an adapter for each channel */

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

		force = 0;			  /* dynamic adap number */

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

		if (pdata) {

			if (num < pdata->num_modes)

			if (num < pdata->num_modes) {

				/* force static number */

				force = pdata->modes[num].adap_id;

			else

				class = pdata->modes[num].class;

			} else

				/* discard unconfigured channels */

				break;

		}



		data->virt_adaps[num] =

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

				force, num, pca954x_select_chan,

				force, num, class, pca954x_select_chan,

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

					? pca954x_deselect_mux : NULL);

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

+1 −1
Original line number Diff line number Diff line
@@ -221,7 +221,7 @@ static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev) 
				(mux->pdata->base_bus_num + i) : 0;



		mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,

						     mux, bus, i,

						     mux, bus, i, 0,

						     i2c_mux_pinctrl_select,

						     deselect);

		if (!mux->busses[i]) {