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