| /* |
| * 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' */ |
| spinlock_t slock; /* protect irq demux */ |
| unsigned out; /* software latch */ |
| unsigned status; /* current status */ |
| |
| 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 = container_of(chip, struct pcf857x, 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 = container_of(chip, struct pcf857x, chip); |
| int value; |
| |
| value = gpio->read(gpio->client); |
| return (value < 0) ? 0 : (value & (1 << offset)); |
| } |
| |
| static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value) |
| { |
| struct pcf857x *gpio = container_of(chip, struct pcf857x, 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, flags; |
| |
| status = gpio->read(gpio->client); |
| |
| spin_lock_irqsave(&gpio->slock, flags); |
| |
| /* |
| * call the interrupt handler iff gpio is used as |
| * interrupt source, just to avoid bad irqs |
| */ |
| |
| change = (gpio->status ^ status); |
| for_each_set_bit(i, &change, gpio->chip.ngpio) |
| handle_nested_irq(irq_find_mapping(gpio->chip.irqdomain, i)); |
| gpio->status = status; |
| |
| spin_unlock_irqrestore(&gpio->slock, flags); |
| |
| return IRQ_HANDLED; |
| } |
| |
| /* |
| * NOP functions |
| */ |
| static void noop(struct irq_data *data) { } |
| |
| static unsigned int noop_ret(struct irq_data *data) |
| { |
| return 0; |
| } |
| |
| static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on) |
| { |
| struct pcf857x *gpio = irq_data_get_irq_chip_data(data); |
| |
| irq_set_irq_wake(gpio->client->irq, on); |
| return 0; |
| } |
| |
| static struct irq_chip pcf857x_irq_chip = { |
| .name = "pcf857x", |
| .irq_startup = noop_ret, |
| .irq_shutdown = noop, |
| .irq_enable = noop, |
| .irq_disable = noop, |
| .irq_ack = noop, |
| .irq_mask = noop, |
| .irq_unmask = noop, |
| .irq_set_wake = pcf857x_irq_set_wake, |
| }; |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| 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); |
| spin_lock_init(&gpio->slock); |
| |
| gpio->chip.base = pdata ? pdata->gpio_base : -1; |
| gpio->chip.can_sleep = true; |
| gpio->chip.dev = &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 = gpiochip_add(&gpio->chip); |
| 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_irq; |
| } |
| |
| 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_irq; |
| |
| gpiochip_set_chained_irqchip(&gpio->chip, &pcf857x_irq_chip, |
| client->irq, NULL); |
| } |
| |
| /* 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_irq: |
| gpiochip_remove(&gpio->chip); |
| |
| 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; |
| } |
| } |
| |
| gpiochip_remove(&gpio->chip); |
| return status; |
| } |
| |
| static struct i2c_driver pcf857x_driver = { |
| .driver = { |
| .name = "pcf857x", |
| .owner = THIS_MODULE, |
| .of_match_table = of_match_ptr(pcf857x_of_table), |
| }, |
| .probe = pcf857x_probe, |
| .remove = pcf857x_remove, |
| .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"); |