Re: [PATCH v2 5/5] input: joystick: Add ADC attached joystick driver.

Jonathan Cameron
2020-02-02T14:58:47Z

On Sun, 26 Jan 2020 17:12:36 +0100
Artur Rojek <contact@artur-rojek.eu> wrote:

> Add a driver for joystick devices connected to ADC controllers
> supporting the Industrial I/O subsystem.
>
> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
> Tested-by: Paul Cercueil <paul@crapouillou.net>
> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

This also looks good to me. Just that dt patch to tidy up.

Thanks,

Jonathan

> ---
>
> Changes:
>
> v2: - sanity check supported channel format on probe,
> - rename adc_joystick_disable to a more sensible adc_joystick_cleanup,
> - enforce correct axis order by checking the `reg` property of
> child nodes
>
> drivers/input/joystick/Kconfig | 10 ++
> drivers/input/joystick/Makefile | 1 +
> drivers/input/joystick/adc-joystick.c | 245 ++++++++++++++++++++++++++
> 3 files changed, 256 insertions(+)
> create mode 100644 drivers/input/joystick/adc-joystick.c
>
> diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
> index 940b744639c7..efbc20ec5099 100644
> --- a/drivers/input/joystick/Kconfig
> +++ b/drivers/input/joystick/Kconfig
> @@ -42,6 +42,16 @@ config JOYSTICK_A3D
> To compile this driver as a module, choose M here: the
> module will be called a3d.
>
> +config JOYSTICK_ADC
> + tristate "Simple joystick connected over ADC"
> + depends on IIO
> + select IIO_BUFFER_CB
> + help
> + Say Y here if you have a simple joystick connected over ADC.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called adc-joystick.
> +
> config JOYSTICK_ADI
> tristate "Logitech ADI digital joysticks and gamepads"
> select GAMEPORT
> diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
> index 8656023f6ef5..58232b3057d3 100644
> --- a/drivers/input/joystick/Makefile
> +++ b/drivers/input/joystick/Makefile
> @@ -6,6 +6,7 @@
> # Each configuration option enables a list of files.
>
> obj-$(CONFIG_JOYSTICK_A3D) += a3d.o
> +obj-$(CONFIG_JOYSTICK_ADC) += adc-joystick.o
> obj-$(CONFIG_JOYSTICK_ADI) += adi.o
> obj-$(CONFIG_JOYSTICK_AMIGA) += amijoy.o
> obj-$(CONFIG_JOYSTICK_AS5011) += as5011.o
> diff --git a/drivers/input/joystick/adc-joystick.c b/drivers/input/joystick/adc-joystick.c
> new file mode 100644
> index 000000000000..9cb9896da26e
> --- /dev/null
> +++ b/drivers/input/joystick/adc-joystick.c
> @@ -0,0 +1,245 @@
> +// 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/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.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, i;
> + bool sign;
> +
> + bytes = joy->chans[0].channel->scan_type.storagebits >> 3;
> +
> + for (i = 0; i < joy->num_chans; ++i) {
> + 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)[i];
> + break;
> + case 2:
> + val = ((const u16 *)data)[i];
> + if (endianness == IIO_BE)
> + val = be16_to_cpu(val);
> + else if (endianness == IIO_LE)
> + val = le16_to_cpu(val);
> + 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);
> + int ret;
> +
> + ret = iio_channel_start_all_cb(joy->buffer);
> + if (ret)
> + dev_err(dev->dev.parent, "Unable to start callback buffer");
> +
> + 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, ret, i;
> +
> + num_axes = device_get_child_node_count(dev);
> + if (!num_axes) {
> + dev_err(dev, "Unable to find child nodes");
> + return -EINVAL;
> + }
> +
> + if (num_axes != joy->num_chans) {
> + dev_err(dev, "Got %d child nodes for %d channels",
> + 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) {
> + ret = fwnode_property_read_u32(child, "reg", &i);
> + if (ret || i >= num_axes) {
> + dev_err(dev, "reg invalid or missing");
> + goto err;
> + }
> +
> + if (fwnode_property_read_u32(child, "linux,code",
> + &axes[i].code)) {
> + dev_err(dev, "linux,code invalid or missing");
> + goto err;
> + }
> +
> + if (fwnode_property_read_u32_array(child, "abs-range",
> + axes[i].range, 2)) {
> + dev_err(dev, "abs-range invalid or missing");
> + goto err;
> + }
> +
> + 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_handle_put(child);
> + return -EINVAL;
> +}
> +
> +static int adc_joystick_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct adc_joystick *joy;
> + struct input_dev *input;
> + int bits, ret, 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)) {
> + ret = PTR_ERR(joy->chans);
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "Unable to get IIO channels");
> + return ret;
> + }
> +
> + /* Count how many channels we got. NULL terminated. */
> + while (joy->chans[joy->num_chans].indio_dev)
> + joy->num_chans++;
> +
> + bits = joy->chans[0].channel->scan_type.storagebits;
> + if (!bits || (bits >> 3) > 2) {
> + dev_err(dev, "Unsupported channel storage size");
> + return -EINVAL;
> + }
> + for (i = 1; i < joy->num_chans; ++i)
> + if (joy->chans[i].channel->scan_type.storagebits != bits) {
> + dev_err(dev, "Channels must have equal storage size");
> + return -EINVAL;
> + }
> +
> + input = devm_input_allocate_device(dev);
> + if (!input) {
> + dev_err(dev, "Unable to allocate input device");
> + return -ENOMEM;
> + }
> +
> + joy->input = input;
> + input->name = pdev->name;
> + input->id.bustype = BUS_HOST;
> + input->open = adc_joystick_open;
> + input->close = adc_joystick_close;
> +
> + ret = adc_joystick_set_axes(dev, joy);
> + if (ret)
> + return ret;
> +
> + input_set_drvdata(input, joy);
> + ret = input_register_device(input);
> + if (ret) {
> + dev_err(dev, "Unable to register input device: %d", ret);
> + return ret;
> + }
> +
> + 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");
> + return PTR_ERR(joy->buffer);
> + }
> +
> + ret = devm_add_action_or_reset(dev, adc_joystick_cleanup, joy->buffer);
> + if (ret)
> + dev_err(dev, "Unable to add action");
> +
> + return ret;
> +}
> +
> +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 = of_match_ptr(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");