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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>
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@ -88,9 +88,23 @@ static u32 i2c_mux_functionality(struct i2c_adapter *adap)
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return parent->algo->functionality(parent);
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}
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/* Return all parent classes, merged */
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static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)
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{
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unsigned int class = 0;
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do {
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class |= parent->class;
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parent = i2c_parent_is_i2c_adapter(parent);
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} while (parent);
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return class;
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}
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struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
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struct device *mux_dev,
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void *mux_priv, u32 force_nr, u32 chan_id,
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unsigned int class,
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int (*select) (struct i2c_adapter *,
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void *, u32),
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int (*deselect) (struct i2c_adapter *,
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@ -127,6 +141,14 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
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priv->adap.algo_data = priv;
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priv->adap.dev.parent = &parent->dev;
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/* Sanity check on class */
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if (i2c_mux_parent_classes(parent) & class)
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dev_err(&parent->dev,
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"Segment %d behind mux can't share classes with ancestors\n",
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chan_id);
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else
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priv->adap.class = class;
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/*
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* Try to populate the mux adapter's of_node, expands to
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* nothing if !CONFIG_OF.
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@ -104,8 +104,10 @@ static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev)
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for (i = 0; i < pdata->n_values; i++) {
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u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
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unsigned int class = pdata->classes ? pdata->classes[i] : 0;
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mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, i,
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mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
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i, class,
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i2c_mux_gpio_select, deselect);
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if (!mux->adap[i]) {
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ret = -ENODEV;
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@ -354,7 +354,7 @@ static int pca9541_probe(struct i2c_client *client,
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if (pdata)
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force = pdata->modes[0].adap_id;
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data->mux_adap = i2c_add_mux_adapter(adap, &client->dev, client,
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force, 0,
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force, 0, 0,
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pca9541_select_chan,
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pca9541_release_chan);
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@ -186,7 +186,7 @@ static int pca954x_probe(struct i2c_client *client,
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{
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struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
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struct pca954x_platform_data *pdata = client->dev.platform_data;
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int num, force;
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int num, force, class;
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struct pca954x *data;
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int ret = -ENODEV;
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@ -216,18 +216,20 @@ static int pca954x_probe(struct i2c_client *client,
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/* Now create an adapter for each channel */
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for (num = 0; num < chips[data->type].nchans; num++) {
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force = 0; /* dynamic adap number */
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class = 0; /* no class by default */
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if (pdata) {
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if (num < pdata->num_modes)
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if (num < pdata->num_modes) {
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/* force static number */
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force = pdata->modes[num].adap_id;
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else
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class = pdata->modes[num].class;
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} else
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/* discard unconfigured channels */
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break;
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}
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data->virt_adaps[num] =
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i2c_add_mux_adapter(adap, &client->dev, client,
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force, num, pca954x_select_chan,
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force, num, class, pca954x_select_chan,
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(pdata && pdata->modes[num].deselect_on_exit)
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? pca954x_deselect_mux : NULL);
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@ -221,7 +221,7 @@ static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev)
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(mux->pdata->base_bus_num + i) : 0;
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mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
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mux, bus, i,
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mux, bus, i, 0,
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i2c_mux_pinctrl_select,
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deselect);
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if (!mux->busses[i]) {
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@ -21,6 +21,7 @@
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* @values: Array of bitmasks of GPIO settings (low/high) for each
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* position
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* @n_values: Number of multiplexer positions (busses to instantiate)
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* @classes: Optional I2C auto-detection classes
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* @gpios: Array of GPIO numbers used to control MUX
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* @n_gpios: Number of GPIOs used to control MUX
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* @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used
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@ -30,6 +31,7 @@ struct i2c_mux_gpio_platform_data {
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int base_nr;
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const unsigned *values;
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int n_values;
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const unsigned *classes;
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const unsigned *gpios;
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int n_gpios;
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unsigned idle;
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@ -36,6 +36,7 @@
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struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
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struct device *mux_dev,
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void *mux_priv, u32 force_nr, u32 chan_id,
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unsigned int class,
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int (*select) (struct i2c_adapter *,
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void *mux_dev, u32 chan_id),
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int (*deselect) (struct i2c_adapter *,
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@ -36,6 +36,7 @@
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struct pca954x_platform_mode {
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int adap_id;
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unsigned int deselect_on_exit:1;
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unsigned int class;
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};
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/* Per mux/switch data, used with i2c_register_board_info */
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