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/*
* Copyright (c) 2006-2022, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2022-3-08 GuEe-GUI the first version
*/
#include <rtthread.h>
#include <rtdevice.h>
#define DBG_TAG "input.keyboard.adc"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
struct adc_keys_button
{
rt_uint32_t voltage;
rt_uint32_t keycode;
};
struct adc_keys
{
struct rt_input_device parent;
struct rt_adc_device *adc_dev;
int channel;
rt_uint32_t num_keys;
rt_uint32_t last_key;
rt_uint32_t keyup_voltage;
struct adc_keys_button kbtn[];
};
static void adc_keys_poll(struct rt_input_device *idev)
{
int value, keycode = 0;
rt_uint32_t diff, closest = 0xffffffff;
struct adc_keys *tk = rt_container_of(idev, struct adc_keys, parent);
value = rt_adc_read(tk->adc_dev, tk->channel);
if (value < 0)
{
/* Forcibly release key if any was pressed */
value = tk->keyup_voltage;
}
else
{
for (int i = 0; i < tk->num_keys; ++i)
{
rt_uint32_t sample = (rt_uint32_t)value;
diff = tk->kbtn[i].voltage > sample ? tk->kbtn[i].voltage - sample : sample - tk->kbtn[i].voltage;
if (diff < closest)
{
closest = diff;
keycode = tk->kbtn[i].keycode;
}
}
}
if (value >= 0)
{
rt_uint32_t sample = (rt_uint32_t)value;
rt_uint32_t keyup_diff = tk->keyup_voltage > sample ? tk->keyup_voltage - sample : sample - tk->keyup_voltage;
if (keyup_diff < closest)
{
keycode = 0;
}
}
if (tk->last_key && tk->last_key != keycode)
{
rt_input_report_key(&tk->parent, tk->last_key, 0);
}
if (keycode && tk->last_key != keycode)
{
rt_input_report_key(&tk->parent, keycode, 1);
}
if (tk->last_key != keycode)
{
rt_input_sync(&tk->parent);
}
tk->last_key = keycode;
}
static rt_err_t adc_key_probe(struct rt_platform_device *pdev)
{
int i = 0;
rt_err_t err;
rt_uint32_t interval;
rt_uint32_t num_keys;
struct adc_keys *tk;
struct rt_device *dev = &pdev->parent;
struct rt_ofw_node *np = dev->ofw_node, *key_np;
num_keys = rt_ofw_get_child_count(np);
if (!num_keys)
{
LOG_E("Keymap is missing");
return -RT_EINVAL;
}
tk = rt_calloc(1, sizeof(*tk) + sizeof(struct adc_keys_button) * num_keys);
if (!tk)
{
return -RT_ENOMEM;
}
tk->adc_dev = rt_iio_channel_get_by_name(dev, "buttons", &tk->channel);
if (!tk->adc_dev)
{
LOG_E("ADC device not found");
err = -RT_EINVAL;
goto _fail;
}
rt_ofw_foreach_child_node(np, key_np)
{
const char *propname;
if (rt_ofw_prop_read_u32(key_np, "press-threshold-microvolt",
&tk->kbtn[i].voltage))
{
LOG_E("%s: Key with invalid or missing %s",
rt_ofw_node_full_name(key_np), "press-threshold-microvolt");
rt_ofw_node_put(key_np);
err = -RT_EINVAL;
goto _fail;
}
tk->kbtn[i].voltage /= 1000;
if (!(propname = rt_ofw_get_prop_fuzzy_name(key_np, ",code$")) ||
rt_ofw_prop_read_u32(key_np, propname, &tk->kbtn[i].keycode))
{
LOG_E("%s: Key with invalid or missing %s",
rt_ofw_node_full_name(key_np), "*,code");
rt_ofw_node_put(key_np);
err = -RT_EINVAL;
goto _fail;
}
rt_input_set_capability(&tk->parent, EV_KEY, tk->kbtn[i].keycode);
++i;
}
tk->num_keys = num_keys;
if (rt_ofw_prop_read_u32(np, "keyup-threshold-microvolt", &tk->keyup_voltage))
{
LOG_E("Invalid or missing keyup voltage");
err = -RT_EINVAL;
goto _fail;
}
tk->keyup_voltage /= 1000;
if (rt_ofw_prop_read_u32(np, "poll-interval", &interval))
{
interval = 200;
}
if ((err = rt_input_setup_polling(&tk->parent, adc_keys_poll)))
{
goto _fail;
}
rt_input_set_poll_interval(&tk->parent, interval);
if ((err = rt_input_device_register(&tk->parent)))
{
goto _fail;
}
dev->user_data = tk;
return RT_EOK;
_fail:
rt_input_remove_config(&tk->parent);
rt_free(tk);
return err;
}
static rt_err_t adc_key_remove(struct rt_platform_device *pdev)
{
struct adc_keys *tk = pdev->parent.user_data;
pdev->parent.user_data = RT_NULL;
rt_input_device_unregister(&tk->parent);
rt_free(tk);
return RT_EOK;
}
static const struct rt_ofw_node_id adc_key_ofw_ids[] = {
{ .compatible = "adc-keys" },
{ /* sentinel */ }
};
static struct rt_platform_driver adc_key_driver = {
.name = "adc-keys",
.ids = adc_key_ofw_ids,
.probe = adc_key_probe,
.remove = adc_key_remove,
};
RT_PLATFORM_DRIVER_EXPORT(adc_key_driver);
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