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Release 4.14 drivers/gpio/gpio-pcf857x.c

Directory: drivers/gpio
/*
 * 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/platform_data/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 },
	{ }
};
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" },
	{ }
};
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); }

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Kuninori Morimoto627.27%133.33%
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static int i2c_read_le8(struct i2c_client *client) { return (int)i2c_smbus_read_byte(client); }

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Kuninori Morimoto525.00%133.33%
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/* 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; }

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David Brownell5498.18%150.00%
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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]; }

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/*-------------------------------------------------------------------------*/
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; }

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David Brownell6692.96%250.00%
Kuninori Morimoto45.63%125.00%
Linus Walleij11.41%125.00%
Total71100.00%4100.00%


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)); }

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David Brownell5186.44%125.00%
Kuninori Morimoto46.78%125.00%
Linus Walleij46.78%250.00%
Total59100.00%4100.00%


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; }

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David Brownell8494.38%250.00%
Kuninori Morimoto44.49%125.00%
Linus Walleij11.12%125.00%
Total89100.00%4100.00%


static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value) { pcf857x_output(chip, offset, value); }

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David Brownell2492.31%150.00%
Kuninori Morimoto27.69%150.00%
Total26100.00%2100.00%

/*-------------------------------------------------------------------------*/
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; }

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/* * NOP functions */
static void noop(struct irq_data *data) { }

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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; }

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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); }

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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); }

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static void pcf857x_irq_bus_lock(struct irq_data *data) { struct pcf857x *gpio = irq_data_get_irq_chip_data(data); mutex_lock(&gpio->lock); }

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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); }

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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_nested(&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_nested_irqchip(&gpio->chip, &pcf857x_irq_chip, client->irq); 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; }

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David Brownell32152.54%313.04%
Geert Uytterhoeven10817.68%313.04%
Kuninori Morimoto548.84%313.04%
Laurent Pinchart498.02%14.35%
Ben Dooks233.76%14.35%
Jean Delvare142.29%28.70%
Jingoo Han121.96%28.70%
Guennadi Liakhovetski81.31%14.35%
Laxman Dewangan81.31%14.35%
Dmitry Baryshkov71.15%14.35%
Linus Walleij60.98%417.39%
George Cherian10.16%14.35%
Total611100.00%23100.00%


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; }

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David Brownell9694.12%133.33%
Jingoo Han43.92%133.33%
Dmitry Baryshkov21.96%133.33%
Total102100.00%3100.00%


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); }

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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); }

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/* 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); }

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module_exit(pcf857x_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("David Brownell");

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David Brownell91347.21%411.43%
Geert Uytterhoeven24712.77%38.57%
Laurent Pinchart1839.46%25.71%
Grygorii Strashko1628.38%25.71%
Kuninori Morimoto1226.31%38.57%
Jean Delvare975.02%25.71%
George Cherian773.98%38.57%
Kishon Vijay Abraham I472.43%12.86%
Ben Dooks231.19%12.86%
Jingoo Han160.83%25.71%
Linus Walleij120.62%514.29%
Dmitry Baryshkov90.47%12.86%
Laxman Dewangan80.41%12.86%
Guennadi Liakhovetski80.41%12.86%
Wolfram Sang70.36%25.71%
Paul Gortmaker20.10%12.86%
Grant C. Likely10.05%12.86%
Total1934100.00%35100.00%
Directory: drivers/gpio
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