// SPDX-License-Identifier: GPL-2.0
/*
* I2C multiplexer
*
* Copyright (c) 2008-2009 Rodolfo Giometti <[email protected]>
* Copyright (c) 2008-2009 Eurotech S.p.A. <[email protected]>
*
* This module supports the PCA954x and PCA984x 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.
*
* It's also compatible to Maxims MAX735x I2C switch chips, which are controlled
* as the NXP PCA9548 and the MAX736x chips that act like the PCA9544.
*
* This includes the:
* MAX7356, MAX7357, MAX7358, MAX7367, MAX7368 and MAX7369
*
* 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 <[email protected]>
* 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 <[email protected]>
* and
* pca9540.c from Jean Delvare <[email protected]>.
*/
#include <linux/device.h>
#include <linux/delay.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/pm.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <dt-bindings/mux/mux.h>
#define PCA954X_MAX_NCHANS 8
#define PCA954X_IRQ_OFFSET 4
/*
* MAX7357's configuration register is writeable after POR, but
* can be locked by setting the basic mode bit. MAX7358 configuration
* register is locked by default and needs to be unlocked first.
* The configuration register holds the following settings:
*/
#define MAX7357_CONF_INT_ENABLE BIT(0)
#define MAX7357_CONF_FLUSH_OUT BIT(1)
#define MAX7357_CONF_RELEASE_INT BIT(2)
#define MAX7357_CONF_DISCON_SINGLE_CHAN BIT(4)
#define MAX7357_CONF_PRECONNECT_TEST BIT(7)
#define MAX7357_POR_DEFAULT_CONF MAX7357_CONF_INT_ENABLE
enum pca_type {
max_7356,
max_7357,
max_7358,
max_7367,
max_7368,
max_7369,
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 i2c_device_identity id;
};
struct pca954x {
const struct chip_desc *chip;
u8 last_chan; /* last register value */
/* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
s32 idle_state;
struct i2c_client *client;
struct irq_domain *irq;
unsigned int irq_mask;
raw_spinlock_t lock;
struct regulator *supply;
struct gpio_desc *reset_gpio;
struct reset_control *reset_cont;
};
/* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */
static const struct chip_desc chips[] = {
[max_7356] = {
.nchans = 8,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[max_7357] = {
.nchans = 8,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
/*
* No interrupt controller support. The interrupt
* provides information about stuck channels.
*/
},
[max_7358] = {
.nchans = 8,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
/*
* No interrupt controller support. The interrupt
* provides information about stuck channels.
*/
},
[max_7367] = {
.nchans = 4,
.muxtype = pca954x_isswi,
.has_irq = 1,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[max_7368] = {
.nchans = 4,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[max_7369] = {
.nchans = 4,
.enable = 0x4,
.muxtype = pca954x_ismux,
.has_irq = 1,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9540] = {
.nchans = 2,
.enable = 0x4,
.muxtype = pca954x_ismux,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9542] = {
.nchans = 2,
.enable = 0x4,
.has_irq = 1,
.muxtype = pca954x_ismux,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9543] = {
.nchans = 2,
.has_irq = 1,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9544] = {
.nchans = 4,
.enable = 0x4,
.has_irq = 1,
.muxtype = pca954x_ismux,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9545] = {
.nchans = 4,
.has_irq = 1,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9546] = {
.nchans = 4,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9547] = {
.nchans = 8,
.enable = 0x8,
.muxtype = pca954x_ismux,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9548] = {
.nchans = 8,
.muxtype = pca954x_isswi,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[pca_9846] = {
.nchans = 4,
.muxtype = pca954x_isswi,
.id = {
.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
.part_id = 0x10b,
},
},
[pca_9847] = {
.nchans = 8,
.enable = 0x8,
.muxtype = pca954x_ismux,
.id = {
.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
.part_id = 0x108,
},
},
[pca_9848] = {
.nchans = 8,
.muxtype = pca954x_isswi,
.id = {
.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
.part_id = 0x10a,
},
},
[pca_9849] = {
.nchans = 4,
.enable = 0x4,
.muxtype = pca954x_ismux,
.id = {
.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
.part_id = 0x109,
},
},
};
static const struct i2c_device_id pca954x_id[] = {
{ "max7356", max_7356 },
{ "max7357", max_7357 },
{ "max7358", max_7358 },
{ "max7367", max_7367 },
{ "max7368", max_7368 },
{ "max7369", max_7369 },
{ "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);
static const struct of_device_id pca954x_of_match[] = {
{ .compatible = "maxim,max7356", .data = &chips[max_7356] },
{ .compatible = "maxim,max7357", .data = &chips[max_7357] },
{ .compatible = "maxim,max7358", .data = &chips[max_7358] },
{ .compatible = "maxim,max7367", .data = &chips[max_7367] },
{ .compatible = "maxim,max7368", .data = &chips[max_7368] },
{ .compatible = "maxim,max7369", .data = &chips[max_7369] },
{ .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);
/* 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)
{
union i2c_smbus_data dummy;
return __i2c_smbus_xfer(adap, client->addr, client->flags,
I2C_SMBUS_WRITE, val,
I2C_SMBUS_BYTE, &dummy);
}
static u8 pca954x_regval(struct pca954x *data, u8 chan)
{
/* We make switches look like muxes, not sure how to be smarter. */
if (data->chip->muxtype == pca954x_ismux)
return chan | data->chip->enable;
else
return 1 << chan;
}
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;
u8 regval;
int ret = 0;
regval = pca954x_regval(data, 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;
s32 idle_state;
idle_state = READ_ONCE(data->idle_state);
if (idle_state >= 0)
/* Set the mux back to a predetermined channel */
return pca954x_select_chan(muxc, idle_state);
if (idle_state == MUX_IDLE_DISCONNECT) {
/* Deselect active channel */
data->last_chan = 0;
return pca954x_reg_write(muxc->parent, client,
data->last_chan);
}
/* otherwise leave as-is */
return 0;
}
static ssize_t idle_state_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
struct pca954x *data = i2c_mux_priv(muxc);
return sprintf(buf, "%d\n", READ_ONCE(data->idle_state));
}
static ssize_t idle_state_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
struct pca954x *data = i2c_mux_priv(muxc);
int val;
int ret;
ret = kstrtoint(buf, 0, &val);
if (ret < 0)
return ret;
if (val != MUX_IDLE_AS_IS && val != MUX_IDLE_DISCONNECT &&
(val < 0 || val >= data->chip->nchans))
return -EINVAL;
i2c_lock_bus(muxc->parent, I2C_LOCK_SEGMENT);
WRITE_ONCE(data->idle_state, val);
/*
* Set the mux into a state consistent with the new
* idle_state.
*/
if (data->last_chan || val != MUX_IDLE_DISCONNECT)
ret = pca954x_deselect_mux(muxc, 0);
i2c_unlock_bus(muxc->parent, I2C_LOCK_SEGMENT);
return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(idle_state);
static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
{
struct pca954x *data = dev_id;
unsigned long pending;
int ret, i;
ret = i2c_smbus_read_byte(data->client);
if (ret < 0)
return IRQ_NONE;
pending = (ret >> PCA954X_IRQ_OFFSET) & (BIT(data->chip->nchans) - 1);
for_each_set_bit(i, &pending, data->chip->nchans)
handle_nested_irq(irq_linear_revmap(data->irq, i));
return IRQ_RETVAL(pending);
}
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;
regulator_disable(data->supply);
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);
}
static int pca954x_init(struct i2c_client *client, struct pca954x *data)
{
int ret;
if (data->idle_state >= 0)
data->last_chan = pca954x_regval(data, data->idle_state);
else
data->last_chan = 0; /* Disconnect multiplexer */
if (device_is_compatible(&client->dev, "maxim,max7357")) {
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
u8 conf = MAX7357_POR_DEFAULT_CONF;
/*
* The interrupt signal is shared with the reset pin. Release the
* interrupt after 1.6 seconds to allow using the pin as reset.
*/
conf |= MAX7357_CONF_RELEASE_INT;
if (device_property_read_bool(&client->dev, "maxim,isolate-stuck-channel"))
conf |= MAX7357_CONF_DISCON_SINGLE_CHAN;
if (device_property_read_bool(&client->dev,
"maxim,send-flush-out-sequence"))
conf |= MAX7357_CONF_FLUSH_OUT;
if (device_property_read_bool(&client->dev,
"maxim,preconnection-wiggle-test-enable"))
conf |= MAX7357_CONF_PRECONNECT_TEST;
ret = i2c_smbus_write_byte_data(client, data->last_chan, conf);
} else {
dev_warn(&client->dev, "Write byte data not supported."
"Cannot enable enhanced mode features\n");
ret = i2c_smbus_write_byte(client, data->last_chan);
}
} else {
ret = i2c_smbus_write_byte(client, data->last_chan);
}
if (ret < 0)
data->last_chan = 0;
return ret;
}
static int pca954x_get_reset(struct device *dev, struct pca954x *data)
{
data->reset_cont = devm_reset_control_get_optional_shared(dev, NULL);
if (IS_ERR(data->reset_cont))
return dev_err_probe(dev, PTR_ERR(data->reset_cont),
"Failed to get reset\n");
else if (data->reset_cont)
return 0;
/*
* fallback to legacy reset-gpios
*/
data->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(data->reset_gpio)) {
return dev_err_probe(dev, PTR_ERR(data->reset_gpio),
"Failed to get reset gpio");
}
return 0;
}
static void pca954x_reset_deassert(struct pca954x *data)
{
if (data->reset_cont)
reset_control_deassert(data->reset_cont);
else
gpiod_set_value_cansleep(data->reset_gpio, 0);
}
/*
* I2C init/probing/exit functions
*/
static int pca954x_probe(struct i2c_client *client)
{
const struct i2c_device_id *id = i2c_client_get_device_id(client);
struct i2c_adapter *adap = client->adapter;
struct device *dev = &client->dev;
struct i2c_mux_core *muxc;
struct pca954x *data;
int num;
int ret;
if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
return -ENODEV;
muxc = i2c_mux_alloc(adap, 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;
data->supply = devm_regulator_get(dev, "vdd");
if (IS_ERR(data->supply))
return dev_err_probe(dev, PTR_ERR(data->supply),
"Failed to request regulator\n");
ret = regulator_enable(data->supply);
if (ret)
return dev_err_probe(dev, ret,
"Failed to enable vdd supply\n");
ret = pca954x_get_reset(dev, data);
if (ret)
goto fail_cleanup;
if (data->reset_cont || data->reset_gpio) {
udelay(1);
pca954x_reset_deassert(data);
/* Give the chip some time to recover. */
udelay(1);
}
data->chip = device_get_match_data(dev);
if (!data->chip)
data->chip = &chips[id->driver_data];
if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
struct i2c_device_identity id;
ret = i2c_get_device_id(client, &id);
if (ret && ret != -EOPNOTSUPP)
goto fail_cleanup;
if (!ret &&
(id.manufacturer_id != data->chip->id.manufacturer_id ||
id.part_id != data->chip->id.part_id)) {
dev_warn(dev, "unexpected device id %03x-%03x-%x\n",
id.manufacturer_id, id.part_id,
id.die_revision);
ret = -ENODEV;
goto fail_cleanup;
}
}
data->idle_state = MUX_IDLE_AS_IS;
if (device_property_read_u32(dev, "idle-state", &data->idle_state)) {
if (device_property_read_bool(dev, "i2c-mux-idle-disconnect"))
data->idle_state = MUX_IDLE_DISCONNECT;
}
/*
* Write the mux register at addr to verify
* that the mux is in fact present. This also
* initializes the mux to a channel
* or disconnected state.
*/
ret = pca954x_init(client, data);
if (ret < 0) {
dev_warn(dev, "probe failed\n");
ret = -ENODEV;
goto fail_cleanup;
}
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++) {
ret = i2c_mux_add_adapter(muxc, 0, num);
if (ret)
goto fail_cleanup;
}
if (data->irq) {
ret = devm_request_threaded_irq(dev, data->client->irq,
NULL, pca954x_irq_handler,
IRQF_ONESHOT | IRQF_SHARED,
"pca954x", data);
if (ret)
goto fail_cleanup;
}
/*
* The attr probably isn't going to be needed in most cases,
* so don't fail completely on error.
*/
device_create_file(dev, &dev_attr_idle_state);
dev_info(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 void pca954x_remove(struct i2c_client *client)
{
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
device_remove_file(&client->dev, &dev_attr_idle_state);
pca954x_cleanup(muxc);
}
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);
int ret;
ret = pca954x_init(client, data);
if (ret < 0)
dev_err(&client->dev, "failed to verify mux presence\n");
return ret;
}
static DEFINE_SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
static struct i2c_driver pca954x_driver = {
.driver = {
.name = "pca954x",
.pm = pm_sleep_ptr(&pca954x_pm),
.of_match_table = pca954x_of_match,
},
.probe = pca954x_probe,
.remove = pca954x_remove,
.id_table = pca954x_id,
};
module_i2c_driver(pca954x_driver);
MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
MODULE_LICENSE("GPL v2");
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