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- /*
- * Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
- *
- * Copyright (C) 2007 David Brownell
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
- #include <linux/gpio.h>
- #include <linux/i2c.h>
- #include <linux/i2c/pcf857x.h>
- #include <linux/interrupt.h>
- #include <linux/irq.h>
- #include <linux/irqdomain.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/of.h>
- #include <linux/of_device.h>
- #include <linux/slab.h>
- #include <linux/spinlock.h>
- static const struct i2c_device_id pcf857x_id[] = {
- { "pcf8574", 8 },
- { "pcf8574a", 8 },
- { "pca8574", 8 },
- { "pca9670", 8 },
- { "pca9672", 8 },
- { "pca9674", 8 },
- { "pcf8575", 16 },
- { "pca8575", 16 },
- { "pca9671", 16 },
- { "pca9673", 16 },
- { "pca9675", 16 },
- { "max7328", 8 },
- { "max7329", 8 },
- { "tca9554", 8 },
- { }
- };
- MODULE_DEVICE_TABLE(i2c, pcf857x_id);
- #ifdef CONFIG_OF
- static const struct of_device_id pcf857x_of_table[] = {
- { .compatible = "nxp,pcf8574" },
- { .compatible = "nxp,pcf8574a" },
- { .compatible = "nxp,pca8574" },
- { .compatible = "nxp,pca9670" },
- { .compatible = "nxp,pca9672" },
- { .compatible = "nxp,pca9674" },
- { .compatible = "nxp,pcf8575" },
- { .compatible = "nxp,pca8575" },
- { .compatible = "nxp,pca9671" },
- { .compatible = "nxp,pca9673" },
- { .compatible = "nxp,pca9675" },
- { .compatible = "maxim,max7328" },
- { .compatible = "maxim,max7329" },
- { .compatible = "ti,tca9554" },
- { }
- };
- MODULE_DEVICE_TABLE(of, pcf857x_of_table);
- #endif
- /*
- * The pcf857x, pca857x, and pca967x chips only expose one read and one
- * write register. Writing a "one" bit (to match the reset state) lets
- * that pin be used as an input; it's not an open-drain model, but acts
- * a bit like one. This is described as "quasi-bidirectional"; read the
- * chip documentation for details.
- *
- * Many other I2C GPIO expander chips (like the pca953x models) have
- * more complex register models and more conventional circuitry using
- * push/pull drivers. They often use the same 0x20..0x27 addresses as
- * pcf857x parts, making the "legacy" I2C driver model problematic.
- */
- struct pcf857x {
- struct gpio_chip chip;
- struct i2c_client *client;
- struct mutex lock; /* protect 'out' */
- unsigned out; /* software latch */
- unsigned status; /* current status */
- unsigned int irq_parent;
- unsigned irq_enabled; /* enabled irqs */
- int (*write)(struct i2c_client *client, unsigned data);
- int (*read)(struct i2c_client *client);
- };
- /*-------------------------------------------------------------------------*/
- /* Talk to 8-bit I/O expander */
- static int i2c_write_le8(struct i2c_client *client, unsigned data)
- {
- return i2c_smbus_write_byte(client, data);
- }
- static int i2c_read_le8(struct i2c_client *client)
- {
- return (int)i2c_smbus_read_byte(client);
- }
- /* Talk to 16-bit I/O expander */
- static int i2c_write_le16(struct i2c_client *client, unsigned word)
- {
- u8 buf[2] = { word & 0xff, word >> 8, };
- int status;
- status = i2c_master_send(client, buf, 2);
- return (status < 0) ? status : 0;
- }
- static int i2c_read_le16(struct i2c_client *client)
- {
- u8 buf[2];
- int status;
- status = i2c_master_recv(client, buf, 2);
- if (status < 0)
- return status;
- return (buf[1] << 8) | buf[0];
- }
- /*-------------------------------------------------------------------------*/
- static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
- {
- struct pcf857x *gpio = gpiochip_get_data(chip);
- int status;
- mutex_lock(&gpio->lock);
- gpio->out |= (1 << offset);
- status = gpio->write(gpio->client, gpio->out);
- mutex_unlock(&gpio->lock);
- return status;
- }
- static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
- {
- struct pcf857x *gpio = gpiochip_get_data(chip);
- int value;
- value = gpio->read(gpio->client);
- return (value < 0) ? value : !!(value & (1 << offset));
- }
- static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
- {
- struct pcf857x *gpio = gpiochip_get_data(chip);
- unsigned bit = 1 << offset;
- int status;
- mutex_lock(&gpio->lock);
- if (value)
- gpio->out |= bit;
- else
- gpio->out &= ~bit;
- status = gpio->write(gpio->client, gpio->out);
- mutex_unlock(&gpio->lock);
- return status;
- }
- static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
- {
- pcf857x_output(chip, offset, value);
- }
- /*-------------------------------------------------------------------------*/
- static irqreturn_t pcf857x_irq(int irq, void *data)
- {
- struct pcf857x *gpio = data;
- unsigned long change, i, status;
- status = gpio->read(gpio->client);
- /*
- * call the interrupt handler iff gpio is used as
- * interrupt source, just to avoid bad irqs
- */
- mutex_lock(&gpio->lock);
- change = (gpio->status ^ status) & gpio->irq_enabled;
- gpio->status = status;
- mutex_unlock(&gpio->lock);
- for_each_set_bit(i, &change, gpio->chip.ngpio)
- handle_nested_irq(irq_find_mapping(gpio->chip.irqdomain, i));
- return IRQ_HANDLED;
- }
- /*
- * NOP functions
- */
- static void noop(struct irq_data *data) { }
- static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on)
- {
- struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
- int error = 0;
- if (gpio->irq_parent) {
- error = irq_set_irq_wake(gpio->irq_parent, on);
- if (error) {
- dev_dbg(&gpio->client->dev,
- "irq %u doesn't support irq_set_wake\n",
- gpio->irq_parent);
- gpio->irq_parent = 0;
- }
- }
- return error;
- }
- static void pcf857x_irq_enable(struct irq_data *data)
- {
- struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
- gpio->irq_enabled |= (1 << data->hwirq);
- }
- static void pcf857x_irq_disable(struct irq_data *data)
- {
- struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
- gpio->irq_enabled &= ~(1 << data->hwirq);
- }
- static void pcf857x_irq_bus_lock(struct irq_data *data)
- {
- struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
- mutex_lock(&gpio->lock);
- }
- static void pcf857x_irq_bus_sync_unlock(struct irq_data *data)
- {
- struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
- mutex_unlock(&gpio->lock);
- }
- static struct irq_chip pcf857x_irq_chip = {
- .name = "pcf857x",
- .irq_enable = pcf857x_irq_enable,
- .irq_disable = pcf857x_irq_disable,
- .irq_ack = noop,
- .irq_mask = noop,
- .irq_unmask = noop,
- .irq_set_wake = pcf857x_irq_set_wake,
- .irq_bus_lock = pcf857x_irq_bus_lock,
- .irq_bus_sync_unlock = pcf857x_irq_bus_sync_unlock,
- };
- /*-------------------------------------------------------------------------*/
- static int pcf857x_probe(struct i2c_client *client,
- const struct i2c_device_id *id)
- {
- struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
- struct device_node *np = client->dev.of_node;
- struct pcf857x *gpio;
- unsigned int n_latch = 0;
- int status;
- if (IS_ENABLED(CONFIG_OF) && np)
- of_property_read_u32(np, "lines-initial-states", &n_latch);
- else if (pdata)
- n_latch = pdata->n_latch;
- else
- dev_dbg(&client->dev, "no platform data\n");
- /* Allocate, initialize, and register this gpio_chip. */
- gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
- if (!gpio)
- return -ENOMEM;
- mutex_init(&gpio->lock);
- gpio->chip.base = pdata ? pdata->gpio_base : -1;
- gpio->chip.can_sleep = true;
- gpio->chip.parent = &client->dev;
- gpio->chip.owner = THIS_MODULE;
- gpio->chip.get = pcf857x_get;
- gpio->chip.set = pcf857x_set;
- gpio->chip.direction_input = pcf857x_input;
- gpio->chip.direction_output = pcf857x_output;
- gpio->chip.ngpio = id->driver_data;
- /* NOTE: the OnSemi jlc1562b is also largely compatible with
- * these parts, notably for output. It has a low-resolution
- * DAC instead of pin change IRQs; and its inputs can be the
- * result of comparators.
- */
- /* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
- * 9670, 9672, 9764, and 9764a use quite a variety.
- *
- * NOTE: we don't distinguish here between *4 and *4a parts.
- */
- if (gpio->chip.ngpio == 8) {
- gpio->write = i2c_write_le8;
- gpio->read = i2c_read_le8;
- if (!i2c_check_functionality(client->adapter,
- I2C_FUNC_SMBUS_BYTE))
- status = -EIO;
- /* fail if there's no chip present */
- else
- status = i2c_smbus_read_byte(client);
- /* '75/'75c addresses are 0x20..0x27, just like the '74;
- * the '75c doesn't have a current source pulling high.
- * 9671, 9673, and 9765 use quite a variety of addresses.
- *
- * NOTE: we don't distinguish here between '75 and '75c parts.
- */
- } else if (gpio->chip.ngpio == 16) {
- gpio->write = i2c_write_le16;
- gpio->read = i2c_read_le16;
- if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
- status = -EIO;
- /* fail if there's no chip present */
- else
- status = i2c_read_le16(client);
- } else {
- dev_dbg(&client->dev, "unsupported number of gpios\n");
- status = -EINVAL;
- }
- if (status < 0)
- goto fail;
- gpio->chip.label = client->name;
- gpio->client = client;
- i2c_set_clientdata(client, gpio);
- /* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
- * We can't actually know whether a pin is configured (a) as output
- * and driving the signal low, or (b) as input and reporting a low
- * value ... without knowing the last value written since the chip
- * came out of reset (if any). We can't read the latched output.
- *
- * In short, the only reliable solution for setting up pin direction
- * is to do it explicitly. The setup() method can do that, but it
- * may cause transient glitching since it can't know the last value
- * written (some pins may need to be driven low).
- *
- * Using n_latch avoids that trouble. When left initialized to zero,
- * our software copy of the "latch" then matches the chip's all-ones
- * reset state. Otherwise it flags pins to be driven low.
- */
- gpio->out = ~n_latch;
- gpio->status = gpio->out;
- status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
- if (status < 0)
- goto fail;
- /* Enable irqchip if we have an interrupt */
- if (client->irq) {
- status = gpiochip_irqchip_add(&gpio->chip, &pcf857x_irq_chip,
- 0, handle_level_irq,
- IRQ_TYPE_NONE);
- if (status) {
- dev_err(&client->dev, "cannot add irqchip\n");
- goto fail;
- }
- status = devm_request_threaded_irq(&client->dev, client->irq,
- NULL, pcf857x_irq, IRQF_ONESHOT |
- IRQF_TRIGGER_FALLING | IRQF_SHARED,
- dev_name(&client->dev), gpio);
- if (status)
- goto fail;
- gpiochip_set_chained_irqchip(&gpio->chip, &pcf857x_irq_chip,
- client->irq, NULL);
- gpio->irq_parent = client->irq;
- }
- /* Let platform code set up the GPIOs and their users.
- * Now is the first time anyone could use them.
- */
- if (pdata && pdata->setup) {
- status = pdata->setup(client,
- gpio->chip.base, gpio->chip.ngpio,
- pdata->context);
- if (status < 0)
- dev_warn(&client->dev, "setup --> %d\n", status);
- }
- dev_info(&client->dev, "probed\n");
- return 0;
- fail:
- dev_dbg(&client->dev, "probe error %d for '%s'\n", status,
- client->name);
- return status;
- }
- static int pcf857x_remove(struct i2c_client *client)
- {
- struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
- struct pcf857x *gpio = i2c_get_clientdata(client);
- int status = 0;
- if (pdata && pdata->teardown) {
- status = pdata->teardown(client,
- gpio->chip.base, gpio->chip.ngpio,
- pdata->context);
- if (status < 0) {
- dev_err(&client->dev, "%s --> %d\n",
- "teardown", status);
- return status;
- }
- }
- return status;
- }
- static void pcf857x_shutdown(struct i2c_client *client)
- {
- struct pcf857x *gpio = i2c_get_clientdata(client);
- /* Drive all the I/O lines high */
- gpio->write(gpio->client, BIT(gpio->chip.ngpio) - 1);
- }
- static struct i2c_driver pcf857x_driver = {
- .driver = {
- .name = "pcf857x",
- .of_match_table = of_match_ptr(pcf857x_of_table),
- },
- .probe = pcf857x_probe,
- .remove = pcf857x_remove,
- .shutdown = pcf857x_shutdown,
- .id_table = pcf857x_id,
- };
- static int __init pcf857x_init(void)
- {
- return i2c_add_driver(&pcf857x_driver);
- }
- /* register after i2c postcore initcall and before
- * subsys initcalls that may rely on these GPIOs
- */
- subsys_initcall(pcf857x_init);
- static void __exit pcf857x_exit(void)
- {
- i2c_del_driver(&pcf857x_driver);
- }
- module_exit(pcf857x_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("David Brownell");
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