Hi Alexandre,
On Tue, Jul 12, 2016 at 09:36:26PM +0200, Alexandre Belloni wrote:
A common way of multiplexing buttons on a single input in cheap devices is
to use a resistor ladder on an ADC. This driver supports that configuration
by polling an ADC channel provided by IIO.
This looks quite reasonable, just a few small comments.
quoted hunk
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Alexandre Belloni <redacted>
---
drivers/input/keyboard/Kconfig | 15 +++
drivers/input/keyboard/Makefile | 1 +
drivers/input/keyboard/adc-keys.c | 210 ++++++++++++++++++++++++++++++++++++++
3 files changed, 226 insertions(+)
create mode 100644 drivers/input/keyboard/adc-keys.c
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 509608c95994..4cf042cc5e63 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -12,6 +12,21 @@ menuconfig INPUT_KEYBOARD
if INPUT_KEYBOARD
+config KEYBOARD_ADC
+ tristate "ADC ladder Buttons"
+ depends on IIO
+ select INPUT_POLLDEV
+ help
+ This driver implements support for buttons connected
+ to an ADC using a resistor ladder.
+
+ Say Y here if your device has such buttons connected to an ADC. Your
+ board-specific setup logic must also provide a configuration data
+ saying mapping voltages to buttons.
+
+ 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 1d416ddf84e4..d9f4cfcf3410 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 000000000000..cf299ff517a0
--- /dev/null
+++ b/drivers/input/keyboard/adc-keys.c
@@ -0,0 +1,210 @@
+/* Input driver for resistor ladder connected on ADC
+ *
+ * Copyright (c) 2016 Alexandre Belloni
+ *
+ * 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/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/input.h>
+#include <linux/input-polldev.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+
+struct adc_keys_button {
+ u32 voltage;
+ u32 keycode;
+};
+
+struct adc_keys_state {
+ struct iio_channel *channel;
+ u32 num_keys;
+ u32 last_key;
+ u32 keyup_voltage;
+ struct adc_keys_button *map;
const
+};
+
+static void adc_keys_poll(struct input_polled_dev *dev)
+{
+ struct adc_keys_state *st = dev->private;
+ int i, value, ret;
+ u32 diff, closest = 0xffffffff;
+ int keycode = 0;
+
+ ret = iio_read_channel_processed(st->channel, &value);
+ if (ret < 0) {
+ if (st->last_key) {
+ input_report_key(dev->input, st->last_key, 0);
+ input_sync(dev->input);
+ st->last_key = 0;
+ }
+ return;
+ }
+
+ for (i = 0; i < st->num_keys; i++) {
+ diff = abs(st->map[i].voltage - value);
+ if (diff < closest) {
+ closest = diff;
+ keycode = st->map[i].keycode;
+ }
+ }
+
+ if (abs(st->keyup_voltage - value) < closest) {
+ input_report_key(dev->input, st->last_key, 0);
+ st->last_key = 0;
+ } else {
+ if (st->last_key && st->last_key != keycode)
+ input_report_key(dev->input, st->last_key, 0);
+ input_report_key(dev->input, keycode, 1);
+ st->last_key = keycode;
+ }
I think this can be simplified a bit, see version below.
+
+ input_sync(dev->input);
+}
+
+static int adc_keys_load_dt_keymap(struct device *dev,
+ struct adc_keys_state *st)
+{
+ struct device_node *pp, *np = dev->of_node;
+ int i;
+
+ st->num_keys = of_get_child_count(np);
+ if (st->num_keys == 0) {
+ dev_err(dev, "keymap is missing\n");
+ return -EINVAL;
+ }
There is no need to limit this driver to OF, generic device properties
will allow us to use it on DT, ACPI and legacy boards.
+
+ st->map = devm_kmalloc_array(dev, st->num_keys, sizeof(*st->map),
+ GFP_KERNEL);
+ if (!st->map)
+ return -ENOMEM;
+
+ i = 0;
+ for_each_child_of_node(np, pp) {
+ struct adc_keys_button *map = &st->map[i];
+
+ if (of_property_read_u32(pp, "press-threshold-mvolt",
+ &map->voltage)) {
+ dev_err(dev, "%s: Invalid or missing voltage\n",
+ pp->name);
You have to remember to drop node reference if you return early from
for_each_child_of_node().
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32(pp, "linux,code", &map->keycode)) {
+ dev_err(dev, "%s: Invalid or missing linux,code\n",
+ pp->name);
+ return -EINVAL;
+ }
+
+ i++;
+ }
+
+ return 0;
+}
+
+static int adc_keys_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *node = dev->of_node;
+ struct adc_keys_state *st;
+ struct input_polled_dev *poll_dev = NULL;
+ struct input_dev *input;
+ enum iio_chan_type type;
+ int i, value, ret;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ st->channel = devm_iio_channel_get(dev, "buttons");
+ if (IS_ERR(st->channel))
+ return PTR_ERR(st->channel);
+
+ if (!st->channel->indio_dev)
+ return -ENODEV;
+
+ ret = iio_get_channel_type(st->channel, &type);
+ if (ret < 0)
+ return ret;
+
+ if (type != IIO_VOLTAGE) {
+ dev_err(dev, "Incompatible channel type %d\n", type);
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32(node, "keyup-threshold-mvolt",
+ &st->keyup_voltage)) {
+ dev_err(dev, "Invalid or missing keyup voltage\n");
+ return -EINVAL;
+ }
+
+ ret = adc_keys_load_dt_keymap(dev, st);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, st);
+
+ poll_dev = devm_input_allocate_polled_device(dev);
+ if (!poll_dev) {
+ dev_err(dev, "failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ if (!of_property_read_u32(node, "poll-interval", &value))
+ poll_dev->poll_interval = value;
+ poll_dev->poll = adc_keys_poll;
+ poll_dev->private = st;
+
+ input = poll_dev->input;
+
+ input->name = pdev->name;
+ input->phys = "adc-keys/input0";
+ input->dev.parent = &pdev->dev;
No need to do that for devm input devices - it is done for you.
+
+ input->id.bustype = BUS_HOST;
+ input->id.vendor = 0x0001;
+ input->id.product = 0x0001;
+ input->id.version = 0x0100;
+
+ __set_bit(EV_KEY, input->evbit);
+ for (i = 0; i < st->num_keys; i++)
+ __set_bit(st->map[i].keycode, input->keybit);
+
+ if (!!of_get_property(node, "autorepeat", NULL))
+ __set_bit(EV_REP, input->evbit);
+
+ ret = input_register_polled_device(poll_dev);
+ if (ret) {
+ dev_err(dev, "Unable to register input device\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id adc_keys_of_match[] = {
+ { .compatible = "adc-keys", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, adc_keys_of_match);
Needs #ifdef CONFIG_OF.
+
+static struct platform_driver __refdata adc_keys_driver = {
+ .driver = {
+ .name = "adc_keys",
+ .of_match_table = adc_keys_of_match,
of_match_ptr().
+ },
+ .probe = adc_keys_probe,
+};
+
+module_platform_driver(adc_keys_driver);
+
+MODULE_AUTHOR("Alexandre Belloni [off-list ref]");
+MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC");
+MODULE_LICENSE("GPL v2");
--
2.8.1
Thanks.
--
Dmitry
Input: add ADC resistor ladder driver
From: Alexandre Belloni <redacted>
A common way of multiplexing buttons on a single input in cheap devices is
to use a resistor ladder on an ADC. This driver supports that configuration
by polling an ADC channel provided by IIO.
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Alexandre Belloni <redacted>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
.../devicetree/bindings/input/adc-keys.txt | 49 +++++
drivers/input/keyboard/Kconfig | 15 +
drivers/input/keyboard/Makefile | 1
drivers/input/keyboard/adc-keys.c | 208 ++++++++++++++++++++
4 files changed, 273 insertions(+)
create mode 100644 Documentation/devicetree/bindings/input/adc-keys.txt
create mode 100644 drivers/input/keyboard/adc-keys.c
diff --git a/Documentation/devicetree/bindings/input/adc-keys.txt b/Documentation/devicetree/bindings/input/adc-keys.txt
new file mode 100644
index 0000000..feab05a
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/adc-keys.txt
@@ -0,0 +1,49 @@
+ADC attached resistor ladder buttons
+------------------------------------
+
+Required properties:
+ - compatible: "adc-keys"
+ - io-channels: Phandle to an ADC channel
+ - io-channel-names = "buttons";
+ - keyup-threshold-mvolt: Voltage at which all the keys are considered up.
+
+Optional properties:
+ - poll-interval: Poll interval time in milliseconds
+ - autorepeat: Boolean, Enable auto repeat feature of Linux input
+ subsystem.
+
+Each button (key) is represented as a sub-node of "adc-keys":
+
+Required subnode-properties:
+ - label: Descriptive name of the key.
+ - linux,code: Keycode to emit.
+ - press-threshold-mvolt: Voltage adc input when this key is pressed.
+
+Example:
+
+#include <dt-bindings/input/input.h>
+
+ adc-keys {
+ compatible = "adc-keys";
+ io-channels = <&lradc 0>;
+ io-channel-names = "buttons";
+ keyup-threshold-mvolt = <2000>;
+
+ button@1500 {
+ label = "Volume Up";
+ linux,code = <KEY_VOLUMEUP>;
+ press-threshold-mvolt = <1500>;
+ };
+
+ button@1000 {
+ label = "Volume Down";
+ linux,code = <KEY_VOLUMEDOWN>;
+ press-threshold-mvolt = <1000>;
+ };
+
+ button@500 {
+ label = "Enter";
+ linux,code = <KEY_ENTER>;
+ press-threshold-mvolt = <500>;
+ };
+ };diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 509608c..cbd75cf 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -12,6 +12,21 @@ menuconfig INPUT_KEYBOARD
if INPUT_KEYBOARD
+config KEYBOARD_ADC
+ tristate "ADC Ladder Buttons"
+ depends on IIO
+ select INPUT_POLLDEV
+ help
+ This driver implements support for buttons connected
+ to an ADC using a resistor ladder.
+
+ Say Y here if your device has such buttons connected to an ADC. Your
+ board-specific setup logic must also provide a configuration data
+ for mapping voltages to buttons.
+
+ 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 1d416dd..d9f4cfc 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..f91eec5
--- /dev/null
+++ b/drivers/input/keyboard/adc-keys.c
@@ -0,0 +1,208 @@
+/*
+ * Input driver for resistor ladder connected on ADC
+ *
+ * Copyright (c) 2016 Alexandre Belloni
+ *
+ * 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/err.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.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/property.h>
+#include <linux/slab.h>
+
+struct adc_keys_button {
+ u32 voltage;
+ u32 keycode;
+};
+
+struct adc_keys_state {
+ struct iio_channel *channel;
+ u32 num_keys;
+ u32 last_key;
+ u32 keyup_voltage;
+ const struct adc_keys_button *map;
+};
+
+static void adc_keys_poll(struct input_polled_dev *dev)
+{
+ struct adc_keys_state *st = dev->private;
+ int i, value, ret;
+ u32 diff, closest = 0xffffffff;
+ int keycode = 0;
+
+ ret = iio_read_channel_processed(st->channel, &value);
+ if (unlikely(ret < 0)) {
+ /* Forcibly release key if any was pressed */
+ value = st->keyup_voltage;
+ } else {
+ for (i = 0; i < st->num_keys; i++) {
+ diff = abs(st->map[i].voltage - value);
+ if (diff < closest) {
+ closest = diff;
+ keycode = st->map[i].keycode;
+ }
+ }
+ }
+
+ if (abs(st->keyup_voltage - value) < closest)
+ keycode = 0;
+
+ if (st->last_key && st->last_key != keycode)
+ input_report_key(dev->input, st->last_key, 0);
+
+ if (keycode)
+ input_report_key(dev->input, keycode, 1);
+
+ input_sync(dev->input);
+ st->last_key = keycode;
+}
+
+static int adc_keys_load_keymap(struct device *dev, struct adc_keys_state *st)
+{
+ struct adc_keys_button *map;
+ struct fwnode_handle *child;
+ int i;
+
+ st->num_keys = device_get_child_node_count(dev);
+ if (st->num_keys == 0) {
+ dev_err(dev, "keymap is missing\n");
+ return -EINVAL;
+ }
+
+ map = devm_kmalloc_array(dev, st->num_keys, sizeof(*map), GFP_KERNEL);
+ if (!map)
+ return -ENOMEM;
+
+ i = 0;
+ device_for_each_child_node(dev, child) {
+ if (fwnode_property_read_u32(child, "press-threshold-mvolt",
+ &map[i].voltage)) {
+ dev_err(dev, "Key with invalid or missing voltage\n");
+ fwnode_handle_put(child);
+ return -EINVAL;
+ }
+
+ if (fwnode_property_read_u32(child, "linux,code",
+ &map[i].keycode)) {
+ dev_err(dev, "Key with invalid or missing linux,code\n");
+ fwnode_handle_put(child);
+ return -EINVAL;
+ }
+
+ i++;
+ }
+
+ st->map = map;
+ return 0;
+}
+
+static int adc_keys_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct adc_keys_state *st;
+ struct input_polled_dev *poll_dev;
+ struct input_dev *input;
+ enum iio_chan_type type;
+ int i, value;
+ int error;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ st->channel = devm_iio_channel_get(dev, "buttons");
+ if (IS_ERR(st->channel))
+ return PTR_ERR(st->channel);
+
+ if (!st->channel->indio_dev)
+ return -ENXIO;
+
+ error = iio_get_channel_type(st->channel, &type);
+ if (error < 0)
+ return error;
+
+ if (type != IIO_VOLTAGE) {
+ dev_err(dev, "Incompatible channel type %d\n", type);
+ return -EINVAL;
+ }
+
+ if (device_property_read_u32(dev, "keyup-threshold-mvolt",
+ &st->keyup_voltage)) {
+ dev_err(dev, "Invalid or missing keyup voltage\n");
+ return -EINVAL;
+ }
+
+ error = adc_keys_load_keymap(dev, st);
+ if (error)
+ return error;
+
+ platform_set_drvdata(pdev, st);
+
+ poll_dev = devm_input_allocate_polled_device(dev);
+ if (!poll_dev) {
+ dev_err(dev, "failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ if (!device_property_read_u32(dev, "poll-interval", &value))
+ poll_dev->poll_interval = value;
+
+ poll_dev->poll = adc_keys_poll;
+ poll_dev->private = st;
+
+ 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);
+ for (i = 0; i < st->num_keys; i++)
+ __set_bit(st->map[i].keycode, input->keybit);
+
+ if (device_property_read_bool(dev, "autorepeat"))
+ __set_bit(EV_REP, input->evbit);
+
+ error = input_register_polled_device(poll_dev);
+ if (error) {
+ dev_err(dev, "Unable to register input device: %d\n", error);
+ return error;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id adc_keys_of_match[] = {
+ { .compatible = "adc-keys", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, adc_keys_of_match);
+#endif
+
+static struct platform_driver __refdata adc_keys_driver = {
+ .driver = {
+ .name = "adc_keys",
+ .of_match_table = of_match_ptr(adc_keys_of_match),
+ },
+ .probe = adc_keys_probe,
+};
+module_platform_driver(adc_keys_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
+MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC");
+MODULE_LICENSE("GPL v2");On Tue, Jul 12, 2016 at 05:41:50PM -0700, Dmitry Torokhov wrote:
Hi Alexandre,
On Tue, Jul 12, 2016 at 09:36:26PM +0200, Alexandre Belloni wrote:
quoted
A common way of multiplexing buttons on a single input in cheap devices is
to use a resistor ladder on an ADC. This driver supports that configuration
by polling an ADC channel provided by IIO.
This looks quite reasonable, just a few small comments.
Ping.
Did the version below work for you? I am trying sweep in the brand new
drivers before we close merge window.
Thanks!
quoted hunk
quoted
Acked-by: Jonathan Cameron <redacted>
Signed-off-by: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
drivers/input/keyboard/Kconfig | 15 +++
drivers/input/keyboard/Makefile | 1 +
drivers/input/keyboard/adc-keys.c | 210 ++++++++++++++++++++++++++++++++++++++
3 files changed, 226 insertions(+)
create mode 100644 drivers/input/keyboard/adc-keys.c
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 509608c95994..4cf042cc5e63 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -12,6 +12,21 @@ menuconfig INPUT_KEYBOARD
if INPUT_KEYBOARD
+config KEYBOARD_ADC
+ tristate "ADC ladder Buttons"
+ depends on IIO
+ select INPUT_POLLDEV
+ help
+ This driver implements support for buttons connected
+ to an ADC using a resistor ladder.
+
+ Say Y here if your device has such buttons connected to an ADC. Your
+ board-specific setup logic must also provide a configuration data
+ saying mapping voltages to buttons.
+
+ 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 1d416ddf84e4..d9f4cfcf3410 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 000000000000..cf299ff517a0
--- /dev/null
+++ b/drivers/input/keyboard/adc-keys.c
@@ -0,0 +1,210 @@
+/* Input driver for resistor ladder connected on ADC
+ *
+ * Copyright (c) 2016 Alexandre Belloni
+ *
+ * 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/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/input.h>
+#include <linux/input-polldev.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+
+struct adc_keys_button {
+ u32 voltage;
+ u32 keycode;
+};
+
+struct adc_keys_state {
+ struct iio_channel *channel;
+ u32 num_keys;
+ u32 last_key;
+ u32 keyup_voltage;
+ struct adc_keys_button *map;
const
quoted
+};
+
+static void adc_keys_poll(struct input_polled_dev *dev)
+{
+ struct adc_keys_state *st = dev->private;
+ int i, value, ret;
+ u32 diff, closest = 0xffffffff;
+ int keycode = 0;
+
+ ret = iio_read_channel_processed(st->channel, &value);
+ if (ret < 0) {
quoted
+ if (st->last_key) {
+ input_report_key(dev->input, st->last_key, 0);
+ input_sync(dev->input);
+ st->last_key = 0;
+ }
+ return;
+ }
+
+ for (i = 0; i < st->num_keys; i++) {
+ diff = abs(st->map[i].voltage - value);
+ if (diff < closest) {
+ closest = diff;
+ keycode = st->map[i].keycode;
+ }
+ }
+
+ if (abs(st->keyup_voltage - value) < closest) {
+ input_report_key(dev->input, st->last_key, 0);
+ st->last_key = 0;
+ } else {
+ if (st->last_key && st->last_key != keycode)
+ input_report_key(dev->input, st->last_key, 0);
+ input_report_key(dev->input, keycode, 1);
+ st->last_key = keycode;
+ }
I think this can be simplified a bit, see version below.
quoted
+
+ input_sync(dev->input);
+}
+
+static int adc_keys_load_dt_keymap(struct device *dev,
+ struct adc_keys_state *st)
+{
+ struct device_node *pp, *np = dev->of_node;
+ int i;
+
+ st->num_keys = of_get_child_count(np);
+ if (st->num_keys == 0) {
+ dev_err(dev, "keymap is missing\n");
+ return -EINVAL;
+ }
There is no need to limit this driver to OF, generic device properties
will allow us to use it on DT, ACPI and legacy boards.
quoted
+
+ st->map = devm_kmalloc_array(dev, st->num_keys, sizeof(*st->map),
+ GFP_KERNEL);
+ if (!st->map)
+ return -ENOMEM;
+
+ i = 0;
+ for_each_child_of_node(np, pp) {
+ struct adc_keys_button *map = &st->map[i];
+
+ if (of_property_read_u32(pp, "press-threshold-mvolt",
+ &map->voltage)) {
+ dev_err(dev, "%s: Invalid or missing voltage\n",
+ pp->name);
You have to remember to drop node reference if you return early from
for_each_child_of_node().
quoted
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32(pp, "linux,code", &map->keycode)) {
+ dev_err(dev, "%s: Invalid or missing linux,code\n",
+ pp->name);
+ return -EINVAL;
+ }
+
+ i++;
+ }
+
+ return 0;
+}
+
+static int adc_keys_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *node = dev->of_node;
+ struct adc_keys_state *st;
+ struct input_polled_dev *poll_dev = NULL;
+ struct input_dev *input;
+ enum iio_chan_type type;
+ int i, value, ret;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ st->channel = devm_iio_channel_get(dev, "buttons");
+ if (IS_ERR(st->channel))
+ return PTR_ERR(st->channel);
+
+ if (!st->channel->indio_dev)
+ return -ENODEV;
+
+ ret = iio_get_channel_type(st->channel, &type);
+ if (ret < 0)
+ return ret;
+
+ if (type != IIO_VOLTAGE) {
+ dev_err(dev, "Incompatible channel type %d\n", type);
+ return -EINVAL;
+ }
+
+ if (of_property_read_u32(node, "keyup-threshold-mvolt",
+ &st->keyup_voltage)) {
+ dev_err(dev, "Invalid or missing keyup voltage\n");
+ return -EINVAL;
+ }
+
+ ret = adc_keys_load_dt_keymap(dev, st);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, st);
+
+ poll_dev = devm_input_allocate_polled_device(dev);
+ if (!poll_dev) {
+ dev_err(dev, "failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ if (!of_property_read_u32(node, "poll-interval", &value))
+ poll_dev->poll_interval = value;
+ poll_dev->poll = adc_keys_poll;
+ poll_dev->private = st;
+
+ input = poll_dev->input;
+
+ input->name = pdev->name;
+ input->phys = "adc-keys/input0";
+ input->dev.parent = &pdev->dev;
No need to do that for devm input devices - it is done for you.
quoted
+
+ input->id.bustype = BUS_HOST;
+ input->id.vendor = 0x0001;
+ input->id.product = 0x0001;
+ input->id.version = 0x0100;
+
+ __set_bit(EV_KEY, input->evbit);
+ for (i = 0; i < st->num_keys; i++)
+ __set_bit(st->map[i].keycode, input->keybit);
+
+ if (!!of_get_property(node, "autorepeat", NULL))
+ __set_bit(EV_REP, input->evbit);
+
+ ret = input_register_polled_device(poll_dev);
+ if (ret) {
+ dev_err(dev, "Unable to register input device\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id adc_keys_of_match[] = {
+ { .compatible = "adc-keys", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, adc_keys_of_match);
Needs #ifdef CONFIG_OF.
quoted
+
+static struct platform_driver __refdata adc_keys_driver = {
+ .driver = {
+ .name = "adc_keys",
+ .of_match_table = adc_keys_of_match,
of_match_ptr().
quoted
+ },
+ .probe = adc_keys_probe,
+};
+
+module_platform_driver(adc_keys_driver);
+
+MODULE_AUTHOR("Alexandre Belloni [off-list ref]");
+MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC");
+MODULE_LICENSE("GPL v2");
--
2.8.1
Thanks.
--
Dmitry
Input: add ADC resistor ladder driver
From: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
A common way of multiplexing buttons on a single input in cheap devices is
to use a resistor ladder on an ADC. This driver supports that configuration
by polling an ADC channel provided by IIO.
Acked-by: Jonathan Cameron <redacted>
Signed-off-by: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Signed-off-by: Dmitry Torokhov <redacted>
---
.../devicetree/bindings/input/adc-keys.txt | 49 +++++
drivers/input/keyboard/Kconfig | 15 +
drivers/input/keyboard/Makefile | 1
drivers/input/keyboard/adc-keys.c | 208 ++++++++++++++++++++
4 files changed, 273 insertions(+)
create mode 100644 Documentation/devicetree/bindings/input/adc-keys.txt
create mode 100644 drivers/input/keyboard/adc-keys.c
diff --git a/Documentation/devicetree/bindings/input/adc-keys.txt b/Documentation/devicetree/bindings/input/adc-keys.txt
new file mode 100644
index 0000000..feab05a
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/adc-keys.txt
@@ -0,0 +1,49 @@
+ADC attached resistor ladder buttons
+------------------------------------
+
+Required properties:
+ - compatible: "adc-keys"
+ - io-channels: Phandle to an ADC channel
+ - io-channel-names = "buttons";
+ - keyup-threshold-mvolt: Voltage at which all the keys are considered up.
+
+Optional properties:
+ - poll-interval: Poll interval time in milliseconds
+ - autorepeat: Boolean, Enable auto repeat feature of Linux input
+ subsystem.
+
+Each button (key) is represented as a sub-node of "adc-keys":
+
+Required subnode-properties:
+ - label: Descriptive name of the key.
+ - linux,code: Keycode to emit.
+ - press-threshold-mvolt: Voltage adc input when this key is pressed.
+
+Example:
+
+#include <dt-bindings/input/input.h>
+
+ adc-keys {
+ compatible = "adc-keys";
+ io-channels = <&lradc 0>;
+ io-channel-names = "buttons";
+ keyup-threshold-mvolt = <2000>;
+
+ button@1500 {
+ label = "Volume Up";
+ linux,code = <KEY_VOLUMEUP>;
+ press-threshold-mvolt = <1500>;
+ };
+
+ button@1000 {
+ label = "Volume Down";
+ linux,code = <KEY_VOLUMEDOWN>;
+ press-threshold-mvolt = <1000>;
+ };
+
+ button@500 {
+ label = "Enter";
+ linux,code = <KEY_ENTER>;
+ press-threshold-mvolt = <500>;
+ };
+ };diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 509608c..cbd75cf 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -12,6 +12,21 @@ menuconfig INPUT_KEYBOARD
if INPUT_KEYBOARD
+config KEYBOARD_ADC
+ tristate "ADC Ladder Buttons"
+ depends on IIO
+ select INPUT_POLLDEV
+ help
+ This driver implements support for buttons connected
+ to an ADC using a resistor ladder.
+
+ Say Y here if your device has such buttons connected to an ADC. Your
+ board-specific setup logic must also provide a configuration data
+ for mapping voltages to buttons.
+
+ 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 1d416dd..d9f4cfc 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..f91eec5
--- /dev/null
+++ b/drivers/input/keyboard/adc-keys.c
@@ -0,0 +1,208 @@
+/*
+ * Input driver for resistor ladder connected on ADC
+ *
+ * Copyright (c) 2016 Alexandre Belloni
+ *
+ * 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/err.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.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/property.h>
+#include <linux/slab.h>
+
+struct adc_keys_button {
+ u32 voltage;
+ u32 keycode;
+};
+
+struct adc_keys_state {
+ struct iio_channel *channel;
+ u32 num_keys;
+ u32 last_key;
+ u32 keyup_voltage;
+ const struct adc_keys_button *map;
+};
+
+static void adc_keys_poll(struct input_polled_dev *dev)
+{
+ struct adc_keys_state *st = dev->private;
+ int i, value, ret;
+ u32 diff, closest = 0xffffffff;
+ int keycode = 0;
+
+ ret = iio_read_channel_processed(st->channel, &value);
+ if (unlikely(ret < 0)) {
+ /* Forcibly release key if any was pressed */
+ value = st->keyup_voltage;
+ } else {
+ for (i = 0; i < st->num_keys; i++) {
+ diff = abs(st->map[i].voltage - value);
+ if (diff < closest) {
+ closest = diff;
+ keycode = st->map[i].keycode;
+ }
+ }
+ }
+
+ if (abs(st->keyup_voltage - value) < closest)
+ keycode = 0;
+
+ if (st->last_key && st->last_key != keycode)
+ input_report_key(dev->input, st->last_key, 0);
+
+ if (keycode)
+ input_report_key(dev->input, keycode, 1);
+
+ input_sync(dev->input);
+ st->last_key = keycode;
+}
+
+static int adc_keys_load_keymap(struct device *dev, struct adc_keys_state *st)
+{
+ struct adc_keys_button *map;
+ struct fwnode_handle *child;
+ int i;
+
+ st->num_keys = device_get_child_node_count(dev);
+ if (st->num_keys == 0) {
+ dev_err(dev, "keymap is missing\n");
+ return -EINVAL;
+ }
+
+ map = devm_kmalloc_array(dev, st->num_keys, sizeof(*map), GFP_KERNEL);
+ if (!map)
+ return -ENOMEM;
+
+ i = 0;
+ device_for_each_child_node(dev, child) {
+ if (fwnode_property_read_u32(child, "press-threshold-mvolt",
+ &map[i].voltage)) {
+ dev_err(dev, "Key with invalid or missing voltage\n");
+ fwnode_handle_put(child);
+ return -EINVAL;
+ }
+
+ if (fwnode_property_read_u32(child, "linux,code",
+ &map[i].keycode)) {
+ dev_err(dev, "Key with invalid or missing linux,code\n");
+ fwnode_handle_put(child);
+ return -EINVAL;
+ }
+
+ i++;
+ }
+
+ st->map = map;
+ return 0;
+}
+
+static int adc_keys_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct adc_keys_state *st;
+ struct input_polled_dev *poll_dev;
+ struct input_dev *input;
+ enum iio_chan_type type;
+ int i, value;
+ int error;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ st->channel = devm_iio_channel_get(dev, "buttons");
+ if (IS_ERR(st->channel))
+ return PTR_ERR(st->channel);
+
+ if (!st->channel->indio_dev)
+ return -ENXIO;
+
+ error = iio_get_channel_type(st->channel, &type);
+ if (error < 0)
+ return error;
+
+ if (type != IIO_VOLTAGE) {
+ dev_err(dev, "Incompatible channel type %d\n", type);
+ return -EINVAL;
+ }
+
+ if (device_property_read_u32(dev, "keyup-threshold-mvolt",
+ &st->keyup_voltage)) {
+ dev_err(dev, "Invalid or missing keyup voltage\n");
+ return -EINVAL;
+ }
+
+ error = adc_keys_load_keymap(dev, st);
+ if (error)
+ return error;
+
+ platform_set_drvdata(pdev, st);
+
+ poll_dev = devm_input_allocate_polled_device(dev);
+ if (!poll_dev) {
+ dev_err(dev, "failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ if (!device_property_read_u32(dev, "poll-interval", &value))
+ poll_dev->poll_interval = value;
+
+ poll_dev->poll = adc_keys_poll;
+ poll_dev->private = st;
+
+ 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);
+ for (i = 0; i < st->num_keys; i++)
+ __set_bit(st->map[i].keycode, input->keybit);
+
+ if (device_property_read_bool(dev, "autorepeat"))
+ __set_bit(EV_REP, input->evbit);
+
+ error = input_register_polled_device(poll_dev);
+ if (error) {
+ dev_err(dev, "Unable to register input device: %d\n", error);
+ return error;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id adc_keys_of_match[] = {
+ { .compatible = "adc-keys", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, adc_keys_of_match);
+#endif
+
+static struct platform_driver __refdata adc_keys_driver = {
+ .driver = {
+ .name = "adc_keys",
+ .of_match_table = of_match_ptr(adc_keys_of_match),
+ },
+ .probe = adc_keys_probe,
+};
+module_platform_driver(adc_keys_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>");
+MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC");
+MODULE_LICENSE("GPL v2");
--
Dmitry
On 28/07/2016 at 15:09:18 -0700, Dmitry Torokhov wrote :
On Tue, Jul 12, 2016 at 05:41:50PM -0700, Dmitry Torokhov wrote:
quoted
Hi Alexandre,
On Tue, Jul 12, 2016 at 09:36:26PM +0200, Alexandre Belloni wrote:
quoted
A common way of multiplexing buttons on a single input in cheap devices is
to use a resistor ladder on an ADC. This driver supports that configuration
by polling an ADC channel provided by IIO.
This looks quite reasonable, just a few small comments.
Ping.
Did the version below work for you? I am trying sweep in the brand new
drivers before we close merge window.
I was thinking it was too late for 4.8. I've juste tested and it works
fine. However, I just sent v5 including the exact same changes but
changing mvolt to millivolt as that seemed preferred by Rob. Both
versions haver been tested and are fine for me.
--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
On Fri, Jul 29, 2016 at 12:49:21AM +0200, Alexandre Belloni wrote:
On 28/07/2016 at 15:09:18 -0700, Dmitry Torokhov wrote :
quoted
On Tue, Jul 12, 2016 at 05:41:50PM -0700, Dmitry Torokhov wrote:
quoted
Hi Alexandre,
On Tue, Jul 12, 2016 at 09:36:26PM +0200, Alexandre Belloni wrote:
quoted
A common way of multiplexing buttons on a single input in cheap devices is
to use a resistor ladder on an ADC. This driver supports that configuration
by polling an ADC channel provided by IIO.
This looks quite reasonable, just a few small comments.
Ping.
Did the version below work for you? I am trying sweep in the brand new
drivers before we close merge window.
I was thinking it was too late for 4.8. I've juste tested and it works
Nah, it is OK - the dirver is brand-new so we can't possibly regress
anyone ;)
fine. However, I just sent v5 including the exact same changes but
changing mvolt to millivolt as that seemed preferred by Rob. Both
versions haver been tested and are fine for me.
Let's see if he acks the binding then...
Thanks.
--
Dmitry