From patchwork Wed Jul 13 00:41:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 9226619 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 79D6760868 for ; Wed, 13 Jul 2016 00:42:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 68F4626861 for ; Wed, 13 Jul 2016 00:42:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5CFBF27BFC; Wed, 13 Jul 2016 00:42:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3EFEE26861 for ; Wed, 13 Jul 2016 00:42:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751170AbcGMAmJ (ORCPT ); Tue, 12 Jul 2016 20:42:09 -0400 Received: from mail-pa0-f66.google.com ([209.85.220.66]:34596 "EHLO mail-pa0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750912AbcGMAmI (ORCPT ); Tue, 12 Jul 2016 20:42:08 -0400 Received: by mail-pa0-f66.google.com with SMTP id hh10so1982407pac.1; Tue, 12 Jul 2016 17:41:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=nSE4W0aRU1pXOps65an8XT7P4AOe53Qx7T4aUO5NwI0=; b=jTFPWCJcpUkrahyUZMa59l3MXj0bf98t7ZtoZYjDyH/bK6ElPBNvfDBVXaK6h93hCe N8deN8I+5fbGzBjUtmKuGaeqOrwHqXoqEXywDin/AAVZTXHLrnQGGcfOXGPrc921RtJP KbHeUOHLN2s/bnek5P7oQE2yibjxCWZ/y9HVOUwLyjtXVXOfIb7P8QCNodtyFeGDUXH1 oY/fMhZJbIEkgi0oReokVdsd7/WDjixUk/8TC6SElVPOXbN69SKOEDuJePkThbFWw/96 lFqS0TruqeH/vxE9XFUcGZEbDtGvBhvoWLLM3wPhwUw0El7KvdEyhfS3A9V4akmhkcFT 3eVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=nSE4W0aRU1pXOps65an8XT7P4AOe53Qx7T4aUO5NwI0=; b=Q7nopKduf2NqucEjduFXXxeE0+3Tg/4m8IrO0DDEx1XyEAfiMk33vrO5tzCUQcetTY Nl2MHE6iZ0PBMsKY01IBw78fsrlV0j+be05tKt0xeE2a4rB5hrX7zp1JuOmYZZAMOpXa CpDR03UAAl/VunAS9Mry1FVv1cuS4Z6neLKudGqOdh7CaAQC3S2zoWS8d01fS3U6i6S5 QIpSdXlz/IYrcfWrYvOSfQv60ankQavxB3XLC8y1hqX3/X35R58tJGuYA0/jmv5Z8tmn 3UaiU7kya5PdQb8tYUCVF1Wary1vuHoqToOxH2yC43+erpyQ6/nO2HqcYnrQJEwJgmD0 6c4g== X-Gm-Message-State: ALyK8tKGUKFw8QXv1f1q8oDl0gFrsnPkpPgVliY3A3agsA0mVbQo7jGTkLK8mMap4vP8DQ== X-Received: by 10.66.193.39 with SMTP id hl7mr8842433pac.10.1468370512905; Tue, 12 Jul 2016 17:41:52 -0700 (PDT) Received: from dtor-ws ([2620:0:1000:1311:4481:da3:80f6:d975]) by smtp.gmail.com with ESMTPSA id n17sm6608429pfb.38.2016.07.12.17.41.51 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Tue, 12 Jul 2016 17:41:52 -0700 (PDT) Date: Tue, 12 Jul 2016 17:41:50 -0700 From: Dmitry Torokhov To: Alexandre Belloni Cc: Jonathan Cameron , linux-input@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/2] input: add ADC resistor ladder driver Message-ID: <20160713004150.GB24789@dtor-ws> References: <1468352186-14190-1-git-send-email-alexandre.belloni@free-electrons.com> <1468352186-14190-2-git-send-email-alexandre.belloni@free-electrons.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1468352186-14190-2-git-send-email-alexandre.belloni@free-electrons.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. > > Acked-by: Jonathan Cameron > Signed-off-by: Alexandre Belloni > --- > 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +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 "); > +MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC"); > +MODULE_LICENSE("GPL v2"); > -- > 2.8.1 > Thanks. 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 + + adc-keys { + compatible = "adc-keys"; + io-channels = <&lradc 0>; + io-channel-names = "buttons"; + keyup-threshold-mvolt = <2000>; + + button@1500 { + label = "Volume Up"; + linux,code = ; + press-threshold-mvolt = <1500>; + }; + + button@1000 { + label = "Volume Down"; + linux,code = ; + press-threshold-mvolt = <1000>; + }; + + button@500 { + label = "Enter"; + linux,code = ; + 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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 "); +MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC"); +MODULE_LICENSE("GPL v2");