// SPDX-License-Identifier: GPL-2.0
/*
* Input driver for joysticks connected over ADC.
* Copyright (c) 2019-2020 Artur Rojek <[email protected]>
*/
#include <linux/ctype.h>
#include <linux/input.h>
#include <linux/iio/iio.h>
#include <linux/iio/consumer.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/unaligned.h>
struct adc_joystick_axis {
u32 code;
bool inverted;
};
struct adc_joystick {
struct input_dev *input;
struct iio_cb_buffer *buffer;
struct iio_channel *chans;
unsigned int num_chans;
struct adc_joystick_axis axes[] __counted_by(num_chans);
};
static int adc_joystick_invert(struct input_dev *dev,
unsigned int axis, int val)
{
int min = input_abs_get_min(dev, axis);
int max = input_abs_get_max(dev, axis);
return (max + min) - val;
}
static void adc_joystick_poll(struct input_dev *input)
{
struct adc_joystick *joy = input_get_drvdata(input);
int i, val, ret;
for (i = 0; i < joy->num_chans; i++) {
ret = iio_read_channel_raw(&joy->chans[i], &val);
if (ret < 0)
return;
if (joy->axes[i].inverted)
val = adc_joystick_invert(input, i, val);
input_report_abs(input, joy->axes[i].code, val);
}
input_sync(input);
}
static int adc_joystick_handle(const void *data, void *private)
{
struct adc_joystick *joy = private;
enum iio_endian endianness;
int bytes, msb, val, idx, i;
const u16 *data_u16;
bool sign;
bytes = joy->chans[0].channel->scan_type.storagebits >> 3;
for (i = 0; i < joy->num_chans; ++i) {
idx = joy->chans[i].channel->scan_index;
endianness = joy->chans[i].channel->scan_type.endianness;
msb = joy->chans[i].channel->scan_type.realbits - 1;
sign = tolower(joy->chans[i].channel->scan_type.sign) == 's';
switch (bytes) {
case 1:
val = ((const u8 *)data)[idx];
break;
case 2:
data_u16 = (const u16 *)data + idx;
/*
* Data is aligned to the sample size by IIO core.
* Call `get_unaligned_xe16` to hide type casting.
*/
if (endianness == IIO_BE)
val = get_unaligned_be16(data_u16);
else if (endianness == IIO_LE)
val = get_unaligned_le16(data_u16);
else /* IIO_CPU */
val = *data_u16;
break;
default:
return -EINVAL;
}
val >>= joy->chans[i].channel->scan_type.shift;
if (sign)
val = sign_extend32(val, msb);
else
val &= GENMASK(msb, 0);
if (joy->axes[i].inverted)
val = adc_joystick_invert(joy->input, i, val);
input_report_abs(joy->input, joy->axes[i].code, val);
}
input_sync(joy->input);
return 0;
}
static int adc_joystick_open(struct input_dev *dev)
{
struct adc_joystick *joy = input_get_drvdata(dev);
struct device *devp = &dev->dev;
int ret;
ret = iio_channel_start_all_cb(joy->buffer);
if (ret)
dev_err(devp, "Unable to start callback buffer: %d\n", ret);
return ret;
}
static void adc_joystick_close(struct input_dev *dev)
{
struct adc_joystick *joy = input_get_drvdata(dev);
iio_channel_stop_all_cb(joy->buffer);
}
static void adc_joystick_cleanup(void *data)
{
iio_channel_release_all_cb(data);
}
static int adc_joystick_set_axes(struct device *dev, struct adc_joystick *joy)
{
struct adc_joystick_axis *axes = joy->axes;
s32 range[2], fuzz, flat;
unsigned int num_axes;
int error, i;
num_axes = device_get_child_node_count(dev);
if (!num_axes) {
dev_err(dev, "Unable to find child nodes\n");
return -EINVAL;
}
if (num_axes != joy->num_chans) {
dev_err(dev, "Got %d child nodes for %d channels\n",
num_axes, joy->num_chans);
return -EINVAL;
}
device_for_each_child_node_scoped(dev, child) {
error = fwnode_property_read_u32(child, "reg", &i);
if (error) {
dev_err(dev, "reg invalid or missing\n");
return error;
}
if (i >= num_axes) {
dev_err(dev, "No matching axis for reg %d\n", i);
return -EINVAL;
}
error = fwnode_property_read_u32(child, "linux,code",
&axes[i].code);
if (error) {
dev_err(dev, "linux,code invalid or missing\n");
return error;
}
error = fwnode_property_read_u32_array(child, "abs-range",
range, 2);
if (error) {
dev_err(dev, "abs-range invalid or missing\n");
return error;
}
if (range[0] > range[1]) {
dev_dbg(dev, "abs-axis %d inverted\n", i);
axes[i].inverted = true;
swap(range[0], range[1]);
}
if (fwnode_property_read_u32(child, "abs-fuzz", &fuzz))
fuzz = 0;
if (fwnode_property_read_u32(child, "abs-flat", &flat))
flat = 0;
input_set_abs_params(joy->input, axes[i].code,
range[0], range[1], fuzz, flat);
}
return 0;
}
static int adc_joystick_count_channels(struct device *dev,
const struct iio_channel *chans,
bool polled,
unsigned int *num_chans)
{
int bits;
int i;
/*
* Count how many channels we got. NULL terminated.
* Do not check the storage size if using polling.
*/
for (i = 0; chans[i].indio_dev; i++) {
if (polled)
continue;
bits = chans[i].channel->scan_type.storagebits;
if (!bits || bits > 16) {
dev_err(dev, "Unsupported channel storage size\n");
return -EINVAL;
}
if (bits != chans[0].channel->scan_type.storagebits) {
dev_err(dev, "Channels must have equal storage size\n");
return -EINVAL;
}
}
*num_chans = i;
return 0;
}
static int adc_joystick_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct iio_channel *chans;
struct adc_joystick *joy;
struct input_dev *input;
unsigned int poll_interval = 0;
unsigned int num_chans;
int error;
chans = devm_iio_channel_get_all(dev);
error = PTR_ERR_OR_ZERO(chans);
if (error) {
if (error != -EPROBE_DEFER)
dev_err(dev, "Unable to get IIO channels");
return error;
}
error = device_property_read_u32(dev, "poll-interval", &poll_interval);
if (error) {
/* -EINVAL means the property is absent. */
if (error != -EINVAL)
return error;
} else if (poll_interval == 0) {
dev_err(dev, "Unable to get poll-interval\n");
return -EINVAL;
}
error = adc_joystick_count_channels(dev, chans, poll_interval != 0,
&num_chans);
if (error)
return error;
joy = devm_kzalloc(dev, struct_size(joy, axes, num_chans), GFP_KERNEL);
if (!joy)
return -ENOMEM;
joy->chans = chans;
joy->num_chans = num_chans;
input = devm_input_allocate_device(dev);
if (!input) {
dev_err(dev, "Unable to allocate input device\n");
return -ENOMEM;
}
joy->input = input;
input->name = pdev->name;
input->id.bustype = BUS_HOST;
error = adc_joystick_set_axes(dev, joy);
if (error)
return error;
if (poll_interval != 0) {
input_setup_polling(input, adc_joystick_poll);
input_set_poll_interval(input, poll_interval);
} else {
input->open = adc_joystick_open;
input->close = adc_joystick_close;
joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle,
joy);
if (IS_ERR(joy->buffer)) {
dev_err(dev, "Unable to allocate callback buffer\n");
return PTR_ERR(joy->buffer);
}
error = devm_add_action_or_reset(dev, adc_joystick_cleanup,
joy->buffer);
if (error) {
dev_err(dev, "Unable to add action\n");
return error;
}
}
input_set_drvdata(input, joy);
error = input_register_device(input);
if (error) {
dev_err(dev, "Unable to register input device\n");
return error;
}
return 0;
}
static const struct of_device_id adc_joystick_of_match[] = {
{ .compatible = "adc-joystick", },
{ }
};
MODULE_DEVICE_TABLE(of, adc_joystick_of_match);
static struct platform_driver adc_joystick_driver = {
.driver = {
.name = "adc-joystick",
.of_match_table = adc_joystick_of_match,
},
.probe = adc_joystick_probe,
};
module_platform_driver(adc_joystick_driver);
MODULE_DESCRIPTION("Input driver for joysticks connected over ADC");
MODULE_AUTHOR("Artur Rojek <[email protected]>");
MODULE_LICENSE("GPL");
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