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path: root/drivers/gpio/gpio-pcf857x.c
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Diffstat (limited to 'drivers/gpio/gpio-pcf857x.c')
-rw-r--r--drivers/gpio/gpio-pcf857x.c442
1 files changed, 442 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
new file mode 100644
index 0000000000..53b69abe67
--- /dev/null
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
+ *
+ * Copyright (C) 2007 David Brownell
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/property.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);
+
+static const struct of_device_id pcf857x_of_table[] = {
+ { .compatible = "nxp,pcf8574", (void *)8 },
+ { .compatible = "nxp,pcf8574a", (void *)8 },
+ { .compatible = "nxp,pca8574", (void *)8 },
+ { .compatible = "nxp,pca9670", (void *)8 },
+ { .compatible = "nxp,pca9672", (void *)8 },
+ { .compatible = "nxp,pca9674", (void *)8 },
+ { .compatible = "nxp,pcf8575", (void *)16 },
+ { .compatible = "nxp,pca8575", (void *)16 },
+ { .compatible = "nxp,pca9671", (void *)16 },
+ { .compatible = "nxp,pca9673", (void *)16 },
+ { .compatible = "nxp,pca9675", (void *)16 },
+ { .compatible = "maxim,max7328", (void *)8 },
+ { .compatible = "maxim,max7329", (void *)8 },
+ { }
+};
+MODULE_DEVICE_TABLE(of, pcf857x_of_table);
+
+/*
+ * 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 int out; /* software latch */
+ unsigned int status; /* current status */
+ unsigned int irq_enabled; /* enabled irqs */
+
+ int (*write)(struct i2c_client *client, unsigned int data);
+ int (*read)(struct i2c_client *client);
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* Talk to 8-bit I/O expander */
+
+static int i2c_write_le8(struct i2c_client *client, unsigned int data)
+{
+ return i2c_smbus_write_byte(client, data);
+}
+
+static int i2c_read_le8(struct i2c_client *client)
+{
+ return i2c_smbus_read_byte(client);
+}
+
+/* Talk to 16-bit I/O expander */
+
+static int i2c_write_le16(struct i2c_client *client, unsigned int 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 int 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 int 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_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct pcf857x *gpio = gpiochip_get_data(chip);
+ int value = gpio->read(gpio->client);
+
+ if (value < 0)
+ return value;
+
+ *bits &= ~*mask;
+ *bits |= value & *mask;
+
+ return 0;
+}
+
+static int pcf857x_output(struct gpio_chip *chip, unsigned int offset, int value)
+{
+ struct pcf857x *gpio = gpiochip_get_data(chip);
+ unsigned int 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 int offset, int value)
+{
+ pcf857x_output(chip, offset, value);
+}
+
+static void pcf857x_set_multiple(struct gpio_chip *chip, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct pcf857x *gpio = gpiochip_get_data(chip);
+
+ mutex_lock(&gpio->lock);
+ gpio->out &= ~*mask;
+ gpio->out |= *bits & *mask;
+ gpio->write(gpio->client, gpio->out);
+ mutex_unlock(&gpio->lock);
+}
+
+/*-------------------------------------------------------------------------*/
+
+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.irq.domain, 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);
+
+ return irq_set_irq_wake(gpio->client->irq, on);
+}
+
+static void pcf857x_irq_enable(struct irq_data *data)
+{
+ struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
+ irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+ gpiochip_enable_irq(&gpio->chip, hwirq);
+ gpio->irq_enabled |= (1 << hwirq);
+}
+
+static void pcf857x_irq_disable(struct irq_data *data)
+{
+ struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
+ irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+ gpio->irq_enabled &= ~(1 << hwirq);
+ gpiochip_disable_irq(&gpio->chip, 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 const 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,
+ .flags = IRQCHIP_IMMUTABLE,
+ GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int pcf857x_probe(struct i2c_client *client)
+{
+ struct pcf857x *gpio;
+ unsigned int n_latch = 0;
+ int status;
+
+ device_property_read_u32(&client->dev, "lines-initial-states", &n_latch);
+
+ /* 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 = -1;
+ gpio->chip.can_sleep = true;
+ gpio->chip.parent = &client->dev;
+ gpio->chip.owner = THIS_MODULE;
+ gpio->chip.get = pcf857x_get;
+ gpio->chip.get_multiple = pcf857x_get_multiple;
+ gpio->chip.set = pcf857x_set;
+ gpio->chip.set_multiple = pcf857x_set_multiple;
+ gpio->chip.direction_input = pcf857x_input;
+ gpio->chip.direction_output = pcf857x_output;
+ gpio->chip.ngpio = (uintptr_t)i2c_get_match_data(client);
+
+ /* 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->read(gpio->client);
+
+ /* Enable irqchip if we have an interrupt */
+ if (client->irq) {
+ struct gpio_irq_chip *girq;
+
+ 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;
+
+ girq = &gpio->chip.irq;
+ gpio_irq_chip_set_chip(girq, &pcf857x_irq_chip);
+ /* This will let us handle the parent IRQ in the driver */
+ girq->parent_handler = NULL;
+ girq->num_parents = 0;
+ girq->parents = NULL;
+ girq->default_type = IRQ_TYPE_NONE;
+ girq->handler = handle_level_irq;
+ girq->threaded = true;
+ }
+
+ status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
+ if (status < 0)
+ goto fail;
+
+ 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 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 = pcf857x_of_table,
+ },
+ .probe = pcf857x_probe,
+ .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");