linux_dsm_epyc7002/drivers/input/misc/rotary_encoder.c
Dmitry Torokhov a9e340dce3 Input: rotary_encoder - move away from platform data structure
Drop support for platform data passed via a C-structure and switch to
device properties instead, which should make the driver compatible with all
platforms: OF, ACPI and static boards. Static boards should use property
sets to communicate device parameters to the driver.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2016-03-02 15:48:05 -08:00

379 lines
8.6 KiB
C

/*
* rotary_encoder.c
*
* (c) 2009 Daniel Mack <daniel@caiaq.de>
* Copyright (C) 2011 Johan Hovold <jhovold@gmail.com>
*
* state machine code inspired by code from Tim Ruetz
*
* A generic driver for rotary encoders connected to GPIO lines.
* See file:Documentation/input/rotary-encoder.txt for more information
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/property.h>
#define DRV_NAME "rotary-encoder"
struct rotary_encoder {
struct input_dev *input;
struct mutex access_mutex;
u32 steps;
u32 axis;
bool relative_axis;
bool rollover;
unsigned int pos;
struct gpio_desc *gpio_a;
struct gpio_desc *gpio_b;
unsigned int irq_a;
unsigned int irq_b;
bool armed;
unsigned char dir; /* 0 - clockwise, 1 - CCW */
char last_stable;
};
static int rotary_encoder_get_state(struct rotary_encoder *encoder)
{
int a = !!gpiod_get_value_cansleep(encoder->gpio_a);
int b = !!gpiod_get_value_cansleep(encoder->gpio_b);
return ((a << 1) | b);
}
static void rotary_encoder_report_event(struct rotary_encoder *encoder)
{
if (encoder->relative_axis) {
input_report_rel(encoder->input,
encoder->axis, encoder->dir ? -1 : 1);
} else {
unsigned int pos = encoder->pos;
if (encoder->dir) {
/* turning counter-clockwise */
if (encoder->rollover)
pos += encoder->steps;
if (pos)
pos--;
} else {
/* turning clockwise */
if (encoder->rollover || pos < encoder->steps)
pos++;
}
if (encoder->rollover)
pos %= encoder->steps;
encoder->pos = pos;
input_report_abs(encoder->input, encoder->axis, encoder->pos);
}
input_sync(encoder->input);
}
static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
{
struct rotary_encoder *encoder = dev_id;
int state;
mutex_lock(&encoder->access_mutex);
state = rotary_encoder_get_state(encoder);
switch (state) {
case 0x0:
if (encoder->armed) {
rotary_encoder_report_event(encoder);
encoder->armed = false;
}
break;
case 0x1:
case 0x2:
if (encoder->armed)
encoder->dir = state - 1;
break;
case 0x3:
encoder->armed = true;
break;
}
mutex_unlock(&encoder->access_mutex);
return IRQ_HANDLED;
}
static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
{
struct rotary_encoder *encoder = dev_id;
int state;
mutex_lock(&encoder->access_mutex);
state = rotary_encoder_get_state(encoder);
switch (state) {
case 0x00:
case 0x03:
if (state != encoder->last_stable) {
rotary_encoder_report_event(encoder);
encoder->last_stable = state;
}
break;
case 0x01:
case 0x02:
encoder->dir = (encoder->last_stable + state) & 0x01;
break;
}
mutex_unlock(&encoder->access_mutex);
return IRQ_HANDLED;
}
static irqreturn_t rotary_encoder_quarter_period_irq(int irq, void *dev_id)
{
struct rotary_encoder *encoder = dev_id;
unsigned char sum;
int state;
mutex_lock(&encoder->access_mutex);
state = rotary_encoder_get_state(encoder);
/*
* We encode the previous and the current state using a byte.
* The previous state in the MSB nibble, the current state in the LSB
* nibble. Then use a table to decide the direction of the turn.
*/
sum = (encoder->last_stable << 4) + state;
switch (sum) {
case 0x31:
case 0x10:
case 0x02:
case 0x23:
encoder->dir = 0; /* clockwise */
break;
case 0x13:
case 0x01:
case 0x20:
case 0x32:
encoder->dir = 1; /* counter-clockwise */
break;
default:
/*
* Ignore all other values. This covers the case when the
* state didn't change (a spurious interrupt) and the
* cases where the state changed by two steps, making it
* impossible to tell the direction.
*
* In either case, don't report any event and save the
* state for later.
*/
goto out;
}
rotary_encoder_report_event(encoder);
out:
encoder->last_stable = state;
mutex_unlock(&encoder->access_mutex);
return IRQ_HANDLED;
}
static int rotary_encoder_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rotary_encoder *encoder;
struct input_dev *input;
irq_handler_t handler;
u32 steps_per_period;
int err;
encoder = devm_kzalloc(dev, sizeof(struct rotary_encoder), GFP_KERNEL);
if (!encoder)
return -ENOMEM;
mutex_init(&encoder->access_mutex);
device_property_read_u32(dev, "rotary-encoder,steps", &encoder->steps);
err = device_property_read_u32(dev, "rotary-encoder,steps-per-period",
&steps_per_period);
if (err) {
/*
* The 'half-period' property has been deprecated, you must
* use 'steps-per-period' and set an appropriate value, but
* we still need to parse it to maintain compatibility. If
* neither property is present we fall back to the one step
* per period behavior.
*/
steps_per_period = device_property_read_bool(dev,
"rotary-encoder,half-period") ? 2 : 1;
}
encoder->rollover =
device_property_read_bool(dev, "rotary-encoder,rollover");
device_property_read_u32(dev, "linux,axis", &encoder->axis);
encoder->relative_axis =
device_property_read_bool(dev, "rotary-encoder,relative-axis");
encoder->gpio_a = devm_gpiod_get_index(dev, NULL, 0, GPIOD_IN);
if (IS_ERR(encoder->gpio_a)) {
err = PTR_ERR(encoder->gpio_a);
dev_err(dev, "unable to get GPIO at index 0: %d\n", err);
return err;
}
encoder->irq_a = gpiod_to_irq(encoder->gpio_a);
encoder->gpio_b = devm_gpiod_get_index(dev, NULL, 1, GPIOD_IN);
if (IS_ERR(encoder->gpio_b)) {
err = PTR_ERR(encoder->gpio_b);
dev_err(dev, "unable to get GPIO at index 1: %d\n", err);
return err;
}
encoder->irq_b = gpiod_to_irq(encoder->gpio_b);
input = devm_input_allocate_device(dev);
if (!input)
return -ENOMEM;
encoder->input = input;
input->name = pdev->name;
input->id.bustype = BUS_HOST;
input->dev.parent = dev;
if (encoder->relative_axis)
input_set_capability(input, EV_REL, encoder->axis);
else
input_set_abs_params(input,
encoder->axis, 0, encoder->steps, 0, 1);
switch (steps_per_period) {
case 4:
handler = &rotary_encoder_quarter_period_irq;
encoder->last_stable = rotary_encoder_get_state(encoder);
break;
case 2:
handler = &rotary_encoder_half_period_irq;
encoder->last_stable = rotary_encoder_get_state(encoder);
break;
case 1:
handler = &rotary_encoder_irq;
break;
default:
dev_err(dev, "'%d' is not a valid steps-per-period value\n",
steps_per_period);
return -EINVAL;
}
err = devm_request_threaded_irq(dev, encoder->irq_a, NULL, handler,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
IRQF_ONESHOT,
DRV_NAME, encoder);
if (err) {
dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a);
return err;
}
err = devm_request_threaded_irq(dev, encoder->irq_b, NULL, handler,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
IRQF_ONESHOT,
DRV_NAME, encoder);
if (err) {
dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b);
return err;
}
err = input_register_device(input);
if (err) {
dev_err(dev, "failed to register input device\n");
return err;
}
device_init_wakeup(dev,
device_property_read_bool(dev, "wakeup-source"));
platform_set_drvdata(pdev, encoder);
return 0;
}
static int __maybe_unused rotary_encoder_suspend(struct device *dev)
{
struct rotary_encoder *encoder = dev_get_drvdata(dev);
if (device_may_wakeup(dev)) {
enable_irq_wake(encoder->irq_a);
enable_irq_wake(encoder->irq_b);
}
return 0;
}
static int __maybe_unused rotary_encoder_resume(struct device *dev)
{
struct rotary_encoder *encoder = dev_get_drvdata(dev);
if (device_may_wakeup(dev)) {
disable_irq_wake(encoder->irq_a);
disable_irq_wake(encoder->irq_b);
}
return 0;
}
static SIMPLE_DEV_PM_OPS(rotary_encoder_pm_ops,
rotary_encoder_suspend, rotary_encoder_resume);
#ifdef CONFIG_OF
static const struct of_device_id rotary_encoder_of_match[] = {
{ .compatible = "rotary-encoder", },
{ },
};
MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
#endif
static struct platform_driver rotary_encoder_driver = {
.probe = rotary_encoder_probe,
.driver = {
.name = DRV_NAME,
.pm = &rotary_encoder_pm_ops,
.of_match_table = of_match_ptr(rotary_encoder_of_match),
}
};
module_platform_driver(rotary_encoder_driver);
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DESCRIPTION("GPIO rotary encoder driver");
MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold");
MODULE_LICENSE("GPL v2");