Add a polled input driver for a keypad in which the buttons are connected
in resistor ladders to an ADC. The IIO framework is used to claim and
read the ADC channels.
Signed-off-by: Andrew Bresticker <abres...@chromium.org>
---
drivers/input/keyboard/Kconfig | 13 ++
drivers/input/keyboard/Makefile | 1 +
drivers/input/keyboard/adc-keys.c | 291 ++++++++++++++++++++++++++++++++++++++
3 files changed, 305 insertions(+)
create mode 100644 drivers/input/keyboard/adc-keys.c
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index a89ba7c..bbaff9e 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -12,6 +12,19 @@ menuconfig INPUT_KEYBOARD
if INPUT_KEYBOARD
+config KEYBOARD_ADC
+ tristate "ADC Keypad"
+ depends on IIO
+ select INPUT_POLLDEV
+ help
+ This driver supports generic ADC keypads using IIO.
+
+ Say Y here if your device has buttons connected in a resistor ladder
+ to an ADC.
+
+ To compile this driver as a module, choose M here: the module will
+ be called adc-keys.
+
config KEYBOARD_ADP5520
tristate "Keypad Support for ADP5520 PMIC"
depends on PMIC_ADP5520
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 4707678..888fa62 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -4,6 +4,7 @@
# Each configuration option enables a list of files.
+obj-$(CONFIG_KEYBOARD_ADC) += adc-keys.o
obj-$(CONFIG_KEYBOARD_ADP5520) += adp5520-keys.o
obj-$(CONFIG_KEYBOARD_ADP5588) += adp5588-keys.o
obj-$(CONFIG_KEYBOARD_ADP5589) += adp5589-keys.o
diff --git a/drivers/input/keyboard/adc-keys.c
b/drivers/input/keyboard/adc-keys.c
new file mode 100644
index 0000000..1b9bcad
--- /dev/null
+++ b/drivers/input/keyboard/adc-keys.c
@@ -0,0 +1,291 @@
+/*
+ * ADC keypad driver
+ *
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * Based on /drivers/input/keybaord/gpio_keys_polled.c:
+ * Copyright (C) 2007-2010 Gabor Juhos <juh...@openwrt.org>
+ * Copyright (C) 2010 Nuno Goncalves <nuno...@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/iio/consumer.h>
+#include <linux/input.h>
+#include <linux/input-polldev.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct adc_key {
+ const char *desc;
+ unsigned int type;
+ unsigned int code;
+ unsigned int min_uV;
+ unsigned int max_uV;
+};
+
+struct adc_chan_map {
+ struct adc_key *keys;
+ unsigned int num_keys;
+ int last_key;
+};
+
+struct adc_keypad {
+ struct device *dev;
+ struct input_polled_dev *poll_dev;
+ unsigned int poll_interval;
+ bool autorepeat;
+ struct iio_channel *iio_chans;
+ unsigned int num_chans;
+ struct adc_chan_map *chan_map;
+};
+
+static void adc_keypad_poll_chan(struct adc_keypad *keypad, unsigned int chan)
+{
+ struct adc_chan_map *chan_map = &keypad->chan_map[chan];
+ struct input_dev *input = keypad->poll_dev->input;
+ struct adc_key *key;
+ unsigned int adc_uV;
+ int ret, val, i;
+
+ ret = iio_read_channel_processed(&keypad->iio_chans[chan], &val);
+ if (ret < 0) {
+ dev_err(keypad->dev, "Failed to read ADC: %d\n", ret);
+ return;
+ }
+ adc_uV = val * 1000;
+
+ for (i = 0; i < chan_map->num_keys; i++) {
+ if (adc_uV >= chan_map->keys[i].min_uV &&
+ adc_uV <= chan_map->keys[i].max_uV)
+ break;
+ }
+ if (i >= chan_map->num_keys)
+ i = -1;
+
+ if (i != chan_map->last_key) {
+ if (chan_map->last_key >= 0) {
+ key = &chan_map->keys[chan_map->last_key];
+ input_event(input, key->type, key->code, 0);
+ }
+ if (i >= 0) {
+ key = &chan_map->keys[i];
+ input_event(input, key->type, key->code, 1);
+ }
+ input_sync(input);
+ chan_map->last_key = i;
+ }
+}
+
+static void adc_keypad_poll(struct input_polled_dev *poll_dev)
+{
+ struct adc_keypad *keypad = poll_dev->private;
+ unsigned int i;
+
+ for (i = 0; i < keypad->num_chans; i++)
+ adc_keypad_poll_chan(keypad, i);
+}
+
+static int adc_keypad_of_parse_chan(struct adc_keypad *keypad,
+ unsigned int chan)
+{
+ struct device_node *child, *np = keypad->dev->of_node;
+ struct adc_key *keys;
+ unsigned int i = 0;
+ int ret;
+
+ for_each_child_of_node(np, child) {
+ unsigned int c;
+
+ ret = of_property_read_u32(child, "channel", &c);
+ if (ret < 0)
+ continue;
+ if (c != chan)
+ continue;
+ i++;
+ }
+
+ keys = devm_kcalloc(keypad->dev, i, sizeof(*keys), GFP_KERNEL);
+ if (!keys)
+ return -ENOMEM;
+ keypad->chan_map[chan].keys = keys;
+ keypad->chan_map[chan].num_keys = i;
+
+ i = 0;
+ for_each_child_of_node(np, child) {
+ struct adc_key *key = &keys[i];
+ unsigned int c;
+
+ ret = of_property_read_u32(child, "channel", &c);
+ if (ret < 0)
+ continue;
+ if (c != chan)
+ continue;
+
+ ret = of_property_read_string(child, "label", &key->desc);
+ if (ret < 0)
+ return ret;
+
+ ret = of_property_read_u32(child, "min-voltage", &key->min_uV);
+ if (ret < 0)
+ return ret;
+
+ ret = of_property_read_u32(child, "max-voltage", &key->max_uV);
+ if (ret < 0)
+ return ret;
+
+ ret = of_property_read_u32(child, "linux,code", &key->code);
+ if (ret < 0)
+ return ret;
+
+ ret = of_property_read_u32(child, "linux,input-type",
+ &key->type);
+ if (ret < 0)
+ key->type = EV_KEY;
+
+ i++;
+ if (i >= keypad->chan_map[chan].num_keys)
+ break;
+ }
+
+ return 0;
+}
+
+static int adc_keypad_of_parse(struct adc_keypad *keypad)
+{
+ struct device_node *np = keypad->dev->of_node;
+ unsigned int i;
+ int ret;
+
+ keypad->autorepeat = of_property_read_bool(np, "autorepeat");
+ ret = of_property_read_u32(np, "poll-interval", &keypad->poll_interval);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < keypad->num_chans; i++) {
+ ret = adc_keypad_of_parse_chan(keypad, i);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int adc_keypad_probe(struct platform_device *pdev)
+{
+ struct adc_keypad *keypad;
+ struct input_polled_dev *poll_dev;
+ struct input_dev *input;
+ unsigned int i;
+ int ret;
+
+ keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
+ if (!keypad)
+ return -ENOMEM;
+ keypad->dev = &pdev->dev;
+ platform_set_drvdata(pdev, keypad);
+
+ keypad->iio_chans = iio_channel_get_all(&pdev->dev);
+ if (IS_ERR(keypad->iio_chans)) {
+ dev_err(&pdev->dev, "Failed to get IIO channels: %ld\n",
+ PTR_ERR(keypad->iio_chans));
+ return PTR_ERR(keypad->iio_chans);
+ }
+
+ i = 0;
+ while (keypad->iio_chans[i].channel != NULL)
+ i++;
+ keypad->num_chans = i;
+ keypad->chan_map = devm_kcalloc(&pdev->dev, keypad->num_chans,
+ sizeof(*keypad->chan_map), GFP_KERNEL);
+ if (!keypad->chan_map) {
+ ret = -ENOMEM;
+ goto put_chans;
+ }
+
+ ret = adc_keypad_of_parse(keypad);
+ if (ret < 0)
+ goto put_chans;
+
+ poll_dev = devm_input_allocate_polled_device(&pdev->dev);
+ if (!poll_dev) {
+ ret = -ENOMEM;
+ goto put_chans;
+ }
+ keypad->poll_dev = poll_dev;
+
+ poll_dev->private = keypad;
+ poll_dev->poll = adc_keypad_poll;
+ poll_dev->poll_interval = keypad->poll_interval;
+
+ input = poll_dev->input;
+ input->name = pdev->name;
+ input->phys = "adc-keys/input0";
+
+ input->id.bustype = BUS_HOST;
+ input->id.vendor = 0x0001;
+ input->id.product = 0x0001;
+ input->id.version = 0x0100;
+
+ __set_bit(EV_KEY, input->evbit);
+ if (keypad->autorepeat)
+ __set_bit(EV_REP, input->evbit);
+
+ for (i = 0; i < keypad->num_chans; i++) {
+ struct adc_chan_map *chan_map = &keypad->chan_map[i];
+ unsigned int j;
+
+ for (j = 0; j < chan_map->num_keys; j++)
+ input_set_capability(input, chan_map->keys[j].type,
+ chan_map->keys[j].code);
+ }
+
+ ret = input_register_polled_device(poll_dev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to register polled device: %d\n",
+ ret);
+ goto put_chans;
+ }
+
+ return 0;
+
+put_chans:
+ iio_channel_release_all(keypad->iio_chans);
+ return ret;
+}
+
+static int adc_keypad_remove(struct platform_device *pdev)
+{
+ struct adc_keypad *keypad = platform_get_drvdata(pdev);
+
+ input_unregister_polled_device(keypad->poll_dev);
+
+ iio_channel_release_all(keypad->iio_chans);
+
+ return 0;
+}
+
+static const struct of_device_id adc_keypad_of_match[] = {
+ { .compatible = "adc-keys", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, adc_keypad_of_match);
+
+static struct platform_driver adc_keypad_driver = {
+ .probe = adc_keypad_probe,
+ .remove = adc_keypad_remove,
+ .driver = {
+ .name = "adc-keys",
+ .of_match_table = adc_keypad_of_match,
+ },
+};
+module_platform_driver(adc_keypad_driver);
+
+MODULE_DESCRIPTION("ADC keypad driver");
+MODULE_AUTHOR("Andrew Bresticker <abres...@chromium.org>");
+MODULE_LICENSE("GPL v2");
--
2.2.0.rc0.207.ga3a616c
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