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

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/*
* 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 and PCA954x series of I2C multiplexer/switch
* chips made by NXP Semiconductors.
* This includes the:
* PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
* PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
*
* 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,
pca_9846,
pca_9847,
pca_9848,
pca_9849,
};
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,
},
[pca_9846] = {
.nchans = 4,
.muxtype = pca954x_isswi,
},
[pca_9847] = {
.nchans = 8,
.enable = 0x8,
.muxtype = pca954x_ismux,
},
[pca_9848] = {
.nchans = 8,
.muxtype = pca954x_isswi,
},
[pca_9849] = {
.nchans = 4,
.enable = 0x4,
.muxtype = pca954x_ismux,
},
};
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 },
{ "pca9846", pca_9846 },
{ "pca9847", pca_9847 },
{ "pca9848", pca_9848 },
{ "pca9849", pca_9849 },
{ }
};
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] },
{ .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
{ .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
{ .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
{ .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
{}
};
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 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_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, 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);
if (!irq) {
dev_err(&client->dev, "failed irq create map\n");
return -EINVAL;
}
irq_set_chip_data(irq, data);
irq_set_chip_and_handler(irq, &pca954x_irq_chip,
handle_simple_irq);
}
return 0;
}
static void pca954x_cleanup(struct i2c_mux_core *muxc)
{
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);
}
/*
* 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_cleanup;
/* 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_cleanup;
}
if (data->irq) {
ret = devm_request_threaded_irq(&client->dev, data->client->irq,
NULL, pca954x_irq_handler,
IRQF_ONESHOT | IRQF_SHARED,
"pca954x", data);
if (ret)
goto fail_cleanup;
}
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_cleanup:
pca954x_cleanup(muxc);
return ret;
}
static int pca954x_remove(struct i2c_client *client)
{
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
pca954x_cleanup(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");