From eee543e8248150e8fb833943c71f40c7b1724600 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Fri, 5 Oct 2012 22:23:51 +0200 Subject: [PATCH] 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 Cc: Peter Korsgaard Cc: David Daney Cc: Michael Lawnick Cc: Rodolfo Giometti --- drivers/i2c/i2c-mux.c | 22 ++++++++++++++++++++++ drivers/i2c/muxes/i2c-mux-gpio.c | 4 +++- drivers/i2c/muxes/i2c-mux-pca9541.c | 2 +- drivers/i2c/muxes/i2c-mux-pca954x.c | 10 ++++++---- drivers/i2c/muxes/i2c-mux-pinctrl.c | 2 +- include/linux/i2c-mux-gpio.h | 2 ++ include/linux/i2c-mux.h | 1 + include/linux/i2c/pca954x.h | 1 + 8 files changed, 37 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 1038c381aea5..d94e0ce78277 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -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. diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c index 68b1f8ec3436..56889e00c76e 100644 --- a/drivers/i2c/muxes/i2c-mux-gpio.c +++ b/drivers/i2c/muxes/i2c-mux-gpio.c @@ -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; diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c index f8f72f39e0b5..f3b8f9a6a89b 100644 --- a/drivers/i2c/muxes/i2c-mux-pca9541.c +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c @@ -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); diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c index f2dfe0d8fcce..8e4387235b69 100644 --- a/drivers/i2c/muxes/i2c-mux-pca954x.c +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -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); diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c index 46a669763476..5f097f309b9f 100644 --- a/drivers/i2c/muxes/i2c-mux-pinctrl.c +++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c @@ -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]) { diff --git a/include/linux/i2c-mux-gpio.h b/include/linux/i2c-mux-gpio.h index a36343a37ebc..4ea1cc7392bd 100644 --- a/include/linux/i2c-mux-gpio.h +++ b/include/linux/i2c-mux-gpio.h @@ -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; diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h index c79083830014..40cb05a97b46 100644 --- a/include/linux/i2c-mux.h +++ b/include/linux/i2c-mux.h @@ -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 *, diff --git a/include/linux/i2c/pca954x.h b/include/linux/i2c/pca954x.h index 28f1f8d5ab1f..1712677d5904 100644 --- a/include/linux/i2c/pca954x.h +++ b/include/linux/i2c/pca954x.h @@ -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 */ -- 2.20.1