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: Jean 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>
This commit is contained in:
Jean Delvare 2012-10-05 22:23:51 +02:00 committed by Jean Delvare
parent 5f3d2f2e1a
commit eee543e824
8 changed files with 37 additions and 7 deletions

View File

@ -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.

View File

@ -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;

View File

@ -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);

View File

@ -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);

View File

@ -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]) {

View File

@ -21,6 +21,7 @@
* @values: Array of bitmasks of GPIO settings (low/high) for each
* position
* @n_values: Number of multiplexer positions (busses to instantiate)
* @classes: Optional I2C auto-detection classes
* @gpios: Array of GPIO numbers used to control MUX
* @n_gpios: Number of GPIOs used to control MUX
* @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used
@ -30,6 +31,7 @@ struct i2c_mux_gpio_platform_data {
int base_nr;
const unsigned *values;
int n_values;
const unsigned *classes;
const unsigned *gpios;
int n_gpios;
unsigned idle;

View File

@ -36,6 +36,7 @@
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 *mux_dev, u32 chan_id),
int (*deselect) (struct i2c_adapter *,

View File

@ -36,6 +36,7 @@
struct pca954x_platform_mode {
int adap_id;
unsigned int deselect_on_exit:1;
unsigned int class;
};
/* Per mux/switch data, used with i2c_register_board_info */