From patchwork Tue Aug 23 06:16:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vignesh Raghavendra X-Patchwork-Id: 9295005 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 0B12A60757 for ; Tue, 23 Aug 2016 06:19:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F055328AFF for ; Tue, 23 Aug 2016 06:19:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E4BE228B53; Tue, 23 Aug 2016 06:19:41 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5AD9D28AFF for ; Tue, 23 Aug 2016 06:19:41 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bc52R-0005Qz-Pf; Tue, 23 Aug 2016 06:18:19 +0000 Received: from bear.ext.ti.com ([198.47.19.11]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bc52E-0005LV-Q5 for linux-arm-kernel@lists.infradead.org; Tue, 23 Aug 2016 06:18:10 +0000 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id u7N6HQ4d011784; Tue, 23 Aug 2016 01:17:26 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id u7N6HP7i025318; Tue, 23 Aug 2016 01:17:25 -0500 Received: from dlep33.itg.ti.com (157.170.170.75) by DFLE73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.3.294.0; Tue, 23 Aug 2016 01:17:24 -0500 Received: from uda0132425.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id u7N6Guah017186; Tue, 23 Aug 2016 01:17:11 -0500 From: Vignesh R To: Dmitry Torokhov Subject: [PATCH v2 1/2] input: misc: Add generic input driver to read encoded GPIO lines Date: Tue, 23 Aug 2016 11:46:48 +0530 Message-ID: <20160823061649.3394-2-vigneshr@ti.com> X-Mailer: git-send-email 2.9.2 In-Reply-To: <20160823061649.3394-1-vigneshr@ti.com> References: <20160823061649.3394-1-vigneshr@ti.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160822_231807_193945_C09E4A6E X-CRM114-Status: GOOD ( 24.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Moritz Fischer , John Stultz , Vignesh R , Arnd Bergmann , devicetree@vger.kernel.org, Tony Lindgren , Daniel Hung-yu Wu , Russell King , linux-kernel@vger.kernel.org, Grant Grundler , Rob Herring , S Twiss , linux-input@vger.kernel.org, Jorge Ramirez-Ortiz , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 intefacing 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 --- v2: Use decoder,max-value instead of gpio-decoder,max-value. .../devicetree/bindings/input/gpio-decoder.txt | 23 ++++ drivers/input/misc/Kconfig | 12 ++ drivers/input/misc/Makefile | 1 + drivers/input/misc/gpio_decoder.c | 130 +++++++++++++++++++++ 4 files changed, 166 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..f27f083a9075 --- /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 (atleast 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..c44513cac3b7 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 && OF + 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 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..eec0fda6f562 --- /dev/null +++ b/drivers/input/misc/gpio_decoder.c @@ -0,0 +1,130 @@ +/* + * gpio-decoder.c + * + * A generic driver to reads multiple gpio lines and translate the + * encoded numeric value into an input event. + * + * 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. + */ + +#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]); + ret = ret << 1 | val; + } + + 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; + poll_dev->input->dev.parent = dev; + 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; +} + +static const struct of_device_id gpio_decoder_of_match[] = { + { .compatible = "gpio-decoder", }, + { }, +}; +MODULE_DEVICE_TABLE(of, gpio_decoder_of_match); + +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");