diff options
Diffstat (limited to 'drivers/input/joystick/adc-joystick.c')
| -rw-r--r-- | drivers/input/joystick/adc-joystick.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/input/joystick/adc-joystick.c b/drivers/input/joystick/adc-joystick.c new file mode 100644 index 000000000..78ebca7d4 --- /dev/null +++ b/drivers/input/joystick/adc-joystick.c @@ -0,0 +1,264 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Input driver for joysticks connected over ADC. + * Copyright (c) 2019-2020 Artur Rojek <contact@artur-rojek.eu> + */ +#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 <asm/unaligned.h> + +struct adc_joystick_axis { + u32 code; + s32 range[2]; + s32 fuzz; + s32 flat; +}; + +struct adc_joystick { + struct input_dev *input; + struct iio_cb_buffer *buffer; + struct adc_joystick_axis *axes; + struct iio_channel *chans; + int num_chans; +}; + +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); + 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; + struct fwnode_handle *child; + int num_axes, 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; + } + + axes = devm_kmalloc_array(dev, num_axes, sizeof(*axes), GFP_KERNEL); + if (!axes) + return -ENOMEM; + + device_for_each_child_node(dev, child) { + error = fwnode_property_read_u32(child, "reg", &i); + if (error) { + dev_err(dev, "reg invalid or missing\n"); + goto err_fwnode_put; + } + + if (i >= num_axes) { + error = -EINVAL; + dev_err(dev, "No matching axis for reg %d\n", i); + goto err_fwnode_put; + } + + error = fwnode_property_read_u32(child, "linux,code", + &axes[i].code); + if (error) { + dev_err(dev, "linux,code invalid or missing\n"); + goto err_fwnode_put; + } + + error = fwnode_property_read_u32_array(child, "abs-range", + axes[i].range, 2); + if (error) { + dev_err(dev, "abs-range invalid or missing\n"); + goto err_fwnode_put; + } + + fwnode_property_read_u32(child, "abs-fuzz", &axes[i].fuzz); + fwnode_property_read_u32(child, "abs-flat", &axes[i].flat); + + input_set_abs_params(joy->input, axes[i].code, + axes[i].range[0], axes[i].range[1], + axes[i].fuzz, axes[i].flat); + input_set_capability(joy->input, EV_ABS, axes[i].code); + } + + joy->axes = axes; + + return 0; + +err_fwnode_put: + fwnode_handle_put(child); + return error; +} + +static int adc_joystick_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct adc_joystick *joy; + struct input_dev *input; + int error; + int bits; + int i; + + joy = devm_kzalloc(dev, sizeof(*joy), GFP_KERNEL); + if (!joy) + return -ENOMEM; + + joy->chans = devm_iio_channel_get_all(dev); + if (IS_ERR(joy->chans)) { + error = PTR_ERR(joy->chans); + if (error != -EPROBE_DEFER) + dev_err(dev, "Unable to get IIO channels"); + return error; + } + + /* Count how many channels we got. NULL terminated. */ + for (i = 0; joy->chans[i].indio_dev; i++) { + bits = joy->chans[i].channel->scan_type.storagebits; + if (!bits || bits > 16) { + dev_err(dev, "Unsupported channel storage size\n"); + return -EINVAL; + } + if (bits != joy->chans[0].channel->scan_type.storagebits) { + dev_err(dev, "Channels must have equal storage size\n"); + return -EINVAL; + } + } + joy->num_chans = i; + + 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; + input->open = adc_joystick_open; + input->close = adc_joystick_close; + + error = adc_joystick_set_axes(dev, joy); + if (error) + 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; + } + + 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; + } + + 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 <contact@artur-rojek.eu>"); +MODULE_LICENSE("GPL"); |