480 lines
12 KiB
C
480 lines
12 KiB
C
/*
|
|
* I2C multiplexer
|
|
*
|
|
* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
|
|
* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
|
|
*
|
|
* This module supports the PCA954x series of I2C multiplexer/switch chips
|
|
* made by Philips Semiconductors.
|
|
* This includes the:
|
|
* PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
|
|
* and PCA9548.
|
|
*
|
|
* These chips are all controlled via the I2C bus itself, and all have a
|
|
* single 8-bit register. The upstream "parent" bus fans out to two,
|
|
* four, or eight downstream busses or channels; which of these
|
|
* are selected is determined by the chip type and register contents. A
|
|
* mux can select only one sub-bus at a time; a switch can select any
|
|
* combination simultaneously.
|
|
*
|
|
* Based on:
|
|
* pca954x.c from Kumar Gala <galak@kernel.crashing.org>
|
|
* Copyright (C) 2006
|
|
*
|
|
* Based on:
|
|
* pca954x.c from Ken Harrenstien
|
|
* Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
|
|
*
|
|
* Based on:
|
|
* i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
|
|
* and
|
|
* pca9540.c from Jean Delvare <jdelvare@suse.de>.
|
|
*
|
|
* This file is licensed under the terms of the GNU General Public
|
|
* License version 2. This program is licensed "as is" without any
|
|
* warranty of any kind, whether express or implied.
|
|
*/
|
|
|
|
#include <linux/device.h>
|
|
#include <linux/gpio/consumer.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/i2c-mux.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_device.h>
|
|
#include <linux/of_irq.h>
|
|
#include <linux/platform_data/pca954x.h>
|
|
#include <linux/pm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spinlock.h>
|
|
|
|
#define PCA954X_MAX_NCHANS 8
|
|
|
|
#define PCA954X_IRQ_OFFSET 4
|
|
|
|
enum pca_type {
|
|
pca_9540,
|
|
pca_9542,
|
|
pca_9543,
|
|
pca_9544,
|
|
pca_9545,
|
|
pca_9546,
|
|
pca_9547,
|
|
pca_9548,
|
|
};
|
|
|
|
struct chip_desc {
|
|
u8 nchans;
|
|
u8 enable; /* used for muxes only */
|
|
u8 has_irq;
|
|
enum muxtype {
|
|
pca954x_ismux = 0,
|
|
pca954x_isswi
|
|
} muxtype;
|
|
};
|
|
|
|
struct pca954x {
|
|
const struct chip_desc *chip;
|
|
|
|
u8 last_chan; /* last register value */
|
|
u8 deselect;
|
|
struct i2c_client *client;
|
|
|
|
struct irq_domain *irq;
|
|
unsigned int irq_mask;
|
|
raw_spinlock_t lock;
|
|
};
|
|
|
|
/* Provide specs for the PCA954x types we know about */
|
|
static const struct chip_desc chips[] = {
|
|
[pca_9540] = {
|
|
.nchans = 2,
|
|
.enable = 0x4,
|
|
.muxtype = pca954x_ismux,
|
|
},
|
|
[pca_9542] = {
|
|
.nchans = 2,
|
|
.enable = 0x4,
|
|
.has_irq = 1,
|
|
.muxtype = pca954x_ismux,
|
|
},
|
|
[pca_9543] = {
|
|
.nchans = 2,
|
|
.has_irq = 1,
|
|
.muxtype = pca954x_isswi,
|
|
},
|
|
[pca_9544] = {
|
|
.nchans = 4,
|
|
.enable = 0x4,
|
|
.has_irq = 1,
|
|
.muxtype = pca954x_ismux,
|
|
},
|
|
[pca_9545] = {
|
|
.nchans = 4,
|
|
.has_irq = 1,
|
|
.muxtype = pca954x_isswi,
|
|
},
|
|
[pca_9546] = {
|
|
.nchans = 4,
|
|
.muxtype = pca954x_isswi,
|
|
},
|
|
[pca_9547] = {
|
|
.nchans = 8,
|
|
.enable = 0x8,
|
|
.muxtype = pca954x_ismux,
|
|
},
|
|
[pca_9548] = {
|
|
.nchans = 8,
|
|
.muxtype = pca954x_isswi,
|
|
},
|
|
};
|
|
|
|
static const struct i2c_device_id pca954x_id[] = {
|
|
{ "pca9540", pca_9540 },
|
|
{ "pca9542", pca_9542 },
|
|
{ "pca9543", pca_9543 },
|
|
{ "pca9544", pca_9544 },
|
|
{ "pca9545", pca_9545 },
|
|
{ "pca9546", pca_9546 },
|
|
{ "pca9547", pca_9547 },
|
|
{ "pca9548", pca_9548 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(i2c, pca954x_id);
|
|
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id pca954x_of_match[] = {
|
|
{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
|
|
{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
|
|
{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
|
|
{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
|
|
{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
|
|
{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
|
|
{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
|
|
{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
|
|
{}
|
|
};
|
|
MODULE_DEVICE_TABLE(of, pca954x_of_match);
|
|
#endif
|
|
|
|
/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
|
|
for this as they will try to lock adapter a second time */
|
|
static int pca954x_reg_write(struct i2c_adapter *adap,
|
|
struct i2c_client *client, u8 val)
|
|
{
|
|
int ret = -ENODEV;
|
|
|
|
if (adap->algo->master_xfer) {
|
|
struct i2c_msg msg;
|
|
char buf[1];
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = 0;
|
|
msg.len = 1;
|
|
buf[0] = val;
|
|
msg.buf = buf;
|
|
ret = __i2c_transfer(adap, &msg, 1);
|
|
|
|
if (ret >= 0 && ret != 1)
|
|
ret = -EREMOTEIO;
|
|
} else {
|
|
union i2c_smbus_data data;
|
|
ret = adap->algo->smbus_xfer(adap, client->addr,
|
|
client->flags,
|
|
I2C_SMBUS_WRITE,
|
|
val, I2C_SMBUS_BYTE, &data);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
|
|
{
|
|
struct pca954x *data = i2c_mux_priv(muxc);
|
|
struct i2c_client *client = data->client;
|
|
const struct chip_desc *chip = data->chip;
|
|
u8 regval;
|
|
int ret = 0;
|
|
|
|
/* we make switches look like muxes, not sure how to be smarter */
|
|
if (chip->muxtype == pca954x_ismux)
|
|
regval = chan | chip->enable;
|
|
else
|
|
regval = 1 << chan;
|
|
|
|
/* Only select the channel if its different from the last channel */
|
|
if (data->last_chan != regval) {
|
|
ret = pca954x_reg_write(muxc->parent, client, regval);
|
|
data->last_chan = ret < 0 ? 0 : regval;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
|
|
{
|
|
struct pca954x *data = i2c_mux_priv(muxc);
|
|
struct i2c_client *client = data->client;
|
|
|
|
if (!(data->deselect & (1 << chan)))
|
|
return 0;
|
|
|
|
/* Deselect active channel */
|
|
data->last_chan = 0;
|
|
return pca954x_reg_write(muxc->parent, client, data->last_chan);
|
|
}
|
|
|
|
static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
|
|
{
|
|
struct pca954x *data = dev_id;
|
|
unsigned int child_irq;
|
|
int ret, i, handled = 0;
|
|
|
|
ret = i2c_smbus_read_byte(data->client);
|
|
if (ret < 0)
|
|
return IRQ_NONE;
|
|
|
|
for (i = 0; i < data->chip->nchans; i++) {
|
|
if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
|
|
child_irq = irq_linear_revmap(data->irq, i);
|
|
handle_nested_irq(child_irq);
|
|
handled++;
|
|
}
|
|
}
|
|
return handled ? IRQ_HANDLED : IRQ_NONE;
|
|
}
|
|
|
|
static void pca954x_irq_mask(struct irq_data *idata)
|
|
{
|
|
struct pca954x *data = irq_data_get_irq_chip_data(idata);
|
|
unsigned int pos = idata->hwirq;
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&data->lock, flags);
|
|
|
|
data->irq_mask &= ~BIT(pos);
|
|
if (!data->irq_mask)
|
|
disable_irq(data->client->irq);
|
|
|
|
raw_spin_unlock_irqrestore(&data->lock, flags);
|
|
}
|
|
|
|
static void pca954x_irq_unmask(struct irq_data *idata)
|
|
{
|
|
struct pca954x *data = irq_data_get_irq_chip_data(idata);
|
|
unsigned int pos = idata->hwirq;
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&data->lock, flags);
|
|
|
|
if (!data->irq_mask)
|
|
enable_irq(data->client->irq);
|
|
data->irq_mask |= BIT(pos);
|
|
|
|
raw_spin_unlock_irqrestore(&data->lock, flags);
|
|
}
|
|
|
|
static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
|
|
{
|
|
if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
|
|
return -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
static struct irq_chip pca954x_irq_chip = {
|
|
.name = "i2c-mux-pca954x",
|
|
.irq_mask = pca954x_irq_mask,
|
|
.irq_unmask = pca954x_irq_unmask,
|
|
.irq_set_type = pca954x_irq_set_type,
|
|
};
|
|
|
|
static int pca954x_irq_setup(struct i2c_mux_core *muxc)
|
|
{
|
|
struct pca954x *data = i2c_mux_priv(muxc);
|
|
struct i2c_client *client = data->client;
|
|
int c, err, irq;
|
|
|
|
if (!data->chip->has_irq || client->irq <= 0)
|
|
return 0;
|
|
|
|
raw_spin_lock_init(&data->lock);
|
|
|
|
data->irq = irq_domain_add_linear(client->dev.of_node,
|
|
data->chip->nchans,
|
|
&irq_domain_simple_ops, data);
|
|
if (!data->irq)
|
|
return -ENODEV;
|
|
|
|
for (c = 0; c < data->chip->nchans; c++) {
|
|
irq = irq_create_mapping(data->irq, c);
|
|
irq_set_chip_data(irq, data);
|
|
irq_set_chip_and_handler(irq, &pca954x_irq_chip,
|
|
handle_simple_irq);
|
|
}
|
|
|
|
err = devm_request_threaded_irq(&client->dev, data->client->irq, NULL,
|
|
pca954x_irq_handler,
|
|
IRQF_ONESHOT | IRQF_SHARED,
|
|
"pca954x", data);
|
|
if (err)
|
|
goto err_req_irq;
|
|
|
|
disable_irq(data->client->irq);
|
|
|
|
return 0;
|
|
err_req_irq:
|
|
for (c = 0; c < data->chip->nchans; c++) {
|
|
irq = irq_find_mapping(data->irq, c);
|
|
irq_dispose_mapping(irq);
|
|
}
|
|
irq_domain_remove(data->irq);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* I2C init/probing/exit functions
|
|
*/
|
|
static int pca954x_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
|
|
struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
|
|
struct device_node *of_node = client->dev.of_node;
|
|
bool idle_disconnect_dt;
|
|
struct gpio_desc *gpio;
|
|
int num, force, class;
|
|
struct i2c_mux_core *muxc;
|
|
struct pca954x *data;
|
|
const struct of_device_id *match;
|
|
int ret;
|
|
|
|
if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
|
|
return -ENODEV;
|
|
|
|
muxc = i2c_mux_alloc(adap, &client->dev,
|
|
PCA954X_MAX_NCHANS, sizeof(*data), 0,
|
|
pca954x_select_chan, pca954x_deselect_mux);
|
|
if (!muxc)
|
|
return -ENOMEM;
|
|
data = i2c_mux_priv(muxc);
|
|
|
|
i2c_set_clientdata(client, muxc);
|
|
data->client = client;
|
|
|
|
/* Get the mux out of reset if a reset GPIO is specified. */
|
|
gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
|
|
if (IS_ERR(gpio))
|
|
return PTR_ERR(gpio);
|
|
|
|
/* Write the mux register at addr to verify
|
|
* that the mux is in fact present. This also
|
|
* initializes the mux to disconnected state.
|
|
*/
|
|
if (i2c_smbus_write_byte(client, 0) < 0) {
|
|
dev_warn(&client->dev, "probe failed\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
|
|
if (match)
|
|
data->chip = of_device_get_match_data(&client->dev);
|
|
else
|
|
data->chip = &chips[id->driver_data];
|
|
|
|
data->last_chan = 0; /* force the first selection */
|
|
|
|
idle_disconnect_dt = of_node &&
|
|
of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
|
|
|
|
ret = pca954x_irq_setup(muxc);
|
|
if (ret)
|
|
goto fail_del_adapters;
|
|
|
|
/* Now create an adapter for each channel */
|
|
for (num = 0; num < data->chip->nchans; num++) {
|
|
bool idle_disconnect_pd = false;
|
|
|
|
force = 0; /* dynamic adap number */
|
|
class = 0; /* no class by default */
|
|
if (pdata) {
|
|
if (num < pdata->num_modes) {
|
|
/* force static number */
|
|
force = pdata->modes[num].adap_id;
|
|
class = pdata->modes[num].class;
|
|
} else
|
|
/* discard unconfigured channels */
|
|
break;
|
|
idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
|
|
}
|
|
data->deselect |= (idle_disconnect_pd ||
|
|
idle_disconnect_dt) << num;
|
|
|
|
ret = i2c_mux_add_adapter(muxc, force, num, class);
|
|
if (ret)
|
|
goto fail_del_adapters;
|
|
}
|
|
|
|
dev_info(&client->dev,
|
|
"registered %d multiplexed busses for I2C %s %s\n",
|
|
num, data->chip->muxtype == pca954x_ismux
|
|
? "mux" : "switch", client->name);
|
|
|
|
return 0;
|
|
|
|
fail_del_adapters:
|
|
i2c_mux_del_adapters(muxc);
|
|
return ret;
|
|
}
|
|
|
|
static int pca954x_remove(struct i2c_client *client)
|
|
{
|
|
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
|
|
struct pca954x *data = i2c_mux_priv(muxc);
|
|
int c, irq;
|
|
|
|
if (data->irq) {
|
|
for (c = 0; c < data->chip->nchans; c++) {
|
|
irq = irq_find_mapping(data->irq, c);
|
|
irq_dispose_mapping(irq);
|
|
}
|
|
irq_domain_remove(data->irq);
|
|
}
|
|
|
|
i2c_mux_del_adapters(muxc);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int pca954x_resume(struct device *dev)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
|
|
struct pca954x *data = i2c_mux_priv(muxc);
|
|
|
|
data->last_chan = 0;
|
|
return i2c_smbus_write_byte(client, 0);
|
|
}
|
|
#endif
|
|
|
|
static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
|
|
|
|
static struct i2c_driver pca954x_driver = {
|
|
.driver = {
|
|
.name = "pca954x",
|
|
.pm = &pca954x_pm,
|
|
.of_match_table = of_match_ptr(pca954x_of_match),
|
|
},
|
|
.probe = pca954x_probe,
|
|
.remove = pca954x_remove,
|
|
.id_table = pca954x_id,
|
|
};
|
|
|
|
module_i2c_driver(pca954x_driver);
|
|
|
|
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
|
|
MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
|
|
MODULE_LICENSE("GPL v2");
|