From patchwork Wed Aug 24 07:58:58 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vignesh Raghavendra X-Patchwork-Id: 9297037 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 4FBF4607F0 for ; Wed, 24 Aug 2016 08:00:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4388128334 for ; Wed, 24 Aug 2016 08:00:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3700628CD8; Wed, 24 Aug 2016 08:00:56 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable 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 7CA9B28334 for ; Wed, 24 Aug 2016 08:00:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753669AbcHXIAE (ORCPT ); Wed, 24 Aug 2016 04:00:04 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:60828 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753386AbcHXIAC (ORCPT ); Wed, 24 Aug 2016 04:00:02 -0400 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by comal.ext.ti.com (8.13.7/8.13.7) with ESMTP id u7O7xIWj002890; Wed, 24 Aug 2016 02:59:18 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id u7O7xHZs010113; Wed, 24 Aug 2016 02:59:17 -0500 Received: from dflp33.itg.ti.com (10.64.6.16) by DFLE73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.3.294.0; Wed, 24 Aug 2016 02:59:16 -0500 Received: from uda0132425.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp33.itg.ti.com (8.14.3/8.13.8) with ESMTP id u7O7x46Q006659; Wed, 24 Aug 2016 02:59:11 -0500 From: Vignesh R To: Dmitry Torokhov CC: Rob Herring , Mark Rutland , Tony Lindgren , Russell King , Arnd Bergmann , Daniel Hung-yu Wu , Grant Grundler , S Twiss , Vignesh R , Moritz Fischer , Jorge Ramirez-Ortiz , John Stultz , "Andrew F . Davis" , , , , , Subject: [PATCH v3 1/2] input: misc: Add generic input driver to read encoded GPIO lines Date: Wed, 24 Aug 2016 13:28:58 +0530 Message-ID: <20160824075859.30979-2-vigneshr@ti.com> X-Mailer: git-send-email 2.9.2 In-Reply-To: <20160824075859.30979-1-vigneshr@ti.com> References: <20160824075859.30979-1-vigneshr@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a driver to read group of GPIO lines and provide its status as a numerical value as input event to the system. This will help in interfacing devices, that can be connected over GPIOs, that provide input to the system by driving GPIO lines connected to them like a rotary dial or a switch. For example, a rotary switch can be connected to four GPIO lines. The status of the GPIO lines reflect the actual position of the rotary switch dial. For example, if dial points to 9, then the four GPIO lines connected to the switch will read HLLH(0b'1001 = 9). This value can be reported as an ABS_* event to the input subsystem. Signed-off-by: Vignesh R Acked-by: Rob Herring --- v3: Fix comments by Andrew and Dmitry Link to v2: https://lkml.org/lkml/2016/8/23/79 .../devicetree/bindings/input/gpio-decoder.txt | 23 ++++ drivers/input/misc/Kconfig | 12 ++ drivers/input/misc/Makefile | 1 + drivers/input/misc/gpio_decoder.c | 134 +++++++++++++++++++++ 4 files changed, 170 insertions(+) create mode 100644 Documentation/devicetree/bindings/input/gpio-decoder.txt create mode 100644 drivers/input/misc/gpio_decoder.c diff --git a/Documentation/devicetree/bindings/input/gpio-decoder.txt b/Documentation/devicetree/bindings/input/gpio-decoder.txt new file mode 100644 index 000000000000..14a77fb96cf0 --- /dev/null +++ b/Documentation/devicetree/bindings/input/gpio-decoder.txt @@ -0,0 +1,23 @@ +* GPIO Decoder DT bindings + +Required Properties: +- compatible: should be "gpio-decoder" +- gpios: a spec of gpios (at least two) to be decoded to a number with + first entry representing the MSB. + +Optional Properties: +- decoder-max-value: Maximum possible value that can be reported by + the gpios. +- linux,axis: the input subsystem axis to map to (ABS_X/ABS_Y). + Defaults to 0 (ABS_X). + +Example: + gpio-decoder0 { + compatible = "gpio-decoder"; + gpios = <&pca9536 3 GPIO_ACTIVE_HIGH>, + <&pca9536 2 GPIO_ACTIVE_HIGH>, + <&pca9536 1 GPIO_ACTIVE_HIGH>, + <&pca9536 0 GPIO_ACTIVE_HIGH>; + linux,axis = <0>; /* ABS_X */ + decoder-max-value = <9>; + }; diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig index efb0ca871327..7cdb89397d18 100644 --- a/drivers/input/misc/Kconfig +++ b/drivers/input/misc/Kconfig @@ -292,6 +292,18 @@ config INPUT_GPIO_TILT_POLLED To compile this driver as a module, choose M here: the module will be called gpio_tilt_polled. +config INPUT_GPIO_DECODER + tristate "Polled GPIO Decoder Input driver" + depends on GPIOLIB || COMPILE_TEST + select INPUT_POLLDEV + help + Say Y here if you want driver to read status of multiple GPIO + lines and report the encoded value as an absolute integer to + input subsystem. + + To compile this driver as a module, choose M here: the module + will be called gpio_decoder. + config INPUT_IXP4XX_BEEPER tristate "IXP4XX Beeper support" depends on ARCH_IXP4XX diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile index 6a1e5e20fc1c..0b6d025f0487 100644 --- a/drivers/input/misc/Makefile +++ b/drivers/input/misc/Makefile @@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_DRV2667_HAPTICS) += drv2667.o obj-$(CONFIG_INPUT_GP2A) += gp2ap002a00f.o obj-$(CONFIG_INPUT_GPIO_BEEPER) += gpio-beeper.o obj-$(CONFIG_INPUT_GPIO_TILT_POLLED) += gpio_tilt_polled.o +obj-$(CONFIG_INPUT_GPIO_DECODER) += gpio_decoder.o obj-$(CONFIG_INPUT_HISI_POWERKEY) += hisi_powerkey.o obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o obj-$(CONFIG_INPUT_IMS_PCU) += ims-pcu.o diff --git a/drivers/input/misc/gpio_decoder.c b/drivers/input/misc/gpio_decoder.c new file mode 100644 index 000000000000..1c2191d4b143 --- /dev/null +++ b/drivers/input/misc/gpio_decoder.c @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/ + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * A generic driver to read multiple gpio lines and translate the + * encoded numeric value into an input event. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +struct gpio_decoder { + struct input_polled_dev *poll_dev; + struct gpio_descs *input_gpios; + struct device *dev; + u32 axis; + u32 last_stable; +}; + +static unsigned int gpio_decoder_get_gpios_state(struct gpio_decoder + *decoder) +{ + struct gpio_descs *gpios = decoder->input_gpios; + unsigned int ret = 0; + int i, val; + + for (i = 0; i < gpios->ndescs; i++) { + val = gpiod_get_value_cansleep(gpios->desc[i]); + if (val >= 0) { + ret = (ret << 1) | !!val; + } else { + dev_err(decoder->dev, "Error reading gpio\n"); + break; + } + } + + return ret; +} + +static void gpio_decoder_poll_gpios(struct input_polled_dev *poll_dev) +{ + struct gpio_decoder *decoder = poll_dev->private; + unsigned int state = gpio_decoder_get_gpios_state(decoder); + + if (state != decoder->last_stable) { + input_report_abs(poll_dev->input, decoder->axis, state); + input_sync(poll_dev->input); + decoder->last_stable = state; + } +} + +static int gpio_decoder_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct gpio_decoder *decoder; + struct input_polled_dev *poll_dev; + u32 max; + int err; + + decoder = devm_kzalloc(dev, sizeof(struct gpio_decoder), GFP_KERNEL); + if (!decoder) + return -ENOMEM; + + device_property_read_u32(dev, "linux,axis", &decoder->axis); + decoder->input_gpios = devm_gpiod_get_array(dev, NULL, GPIOD_IN); + if (IS_ERR(decoder->input_gpios)) { + dev_err(dev, "unable to acquire input gpios\n"); + return PTR_ERR(decoder->input_gpios); + } + if (decoder->input_gpios->ndescs < 2) { + dev_err(dev, "not enough gpios found\n"); + return -EINVAL; + } + + if (device_property_read_u32(dev, "decoder-max-value", &max)) + max = BIT(decoder->input_gpios->ndescs); + + decoder->dev = dev; + poll_dev = devm_input_allocate_polled_device(decoder->dev); + if (!poll_dev) + return -ENOMEM; + + poll_dev->private = decoder; + poll_dev->poll = gpio_decoder_poll_gpios; + decoder->poll_dev = poll_dev; + + poll_dev->input->name = pdev->name; + poll_dev->input->id.bustype = BUS_HOST; + input_set_abs_params(poll_dev->input, decoder->axis, 0, max, 0, 1); + + err = input_register_polled_device(poll_dev); + if (err) { + dev_err(dev, "failed to register polled device\n"); + return err; + } + platform_set_drvdata(pdev, decoder); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id gpio_decoder_of_match[] = { + { .compatible = "gpio-decoder", }, + { }, +}; +MODULE_DEVICE_TABLE(of, gpio_decoder_of_match); +#endif + +static struct platform_driver gpio_decoder_driver = { + .probe = gpio_decoder_probe, + .driver = { + .name = "gpio-decoder", + .of_match_table = of_match_ptr(gpio_decoder_of_match), + } +}; +module_platform_driver(gpio_decoder_driver); + +MODULE_DESCRIPTION("GPIO decoder input driver"); +MODULE_AUTHOR("Vignesh R "); +MODULE_LICENSE("GPL v2");