From patchwork Wed Jul 16 15:46:42 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamil Debski X-Patchwork-Id: 370780 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 926A7140116 for ; Thu, 17 Jul 2014 01:46:59 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965368AbaGPPq4 (ORCPT ); Wed, 16 Jul 2014 11:46:56 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:65141 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965053AbaGPPqy (ORCPT ); Wed, 16 Jul 2014 11:46:54 -0400 Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0N8T00GSKAI4L640@mailout2.samsung.com>; Thu, 17 Jul 2014 00:46:52 +0900 (KST) X-AuditID: cbfee61b-f79f86d00000144c-77-53c69e6c2d5b Received: from epmmp2 ( [203.254.227.17]) by epcpsbgm2.samsung.com (EPCPMTA) with SMTP id 74.11.05196.C6E96C35; Thu, 17 Jul 2014 00:46:52 +0900 (KST) Received: from AMDC1342.digital.local ([106.116.147.39]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0N8T00IM2AHWBQ40@mmp2.samsung.com>; Thu, 17 Jul 2014 00:46:52 +0900 (KST) From: Kamil Debski To: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org Cc: t.figa@samsung.com, m.szyprowski@samsung.com, linux@roeck-us.net, tklauser@distanz.ch, linux-pwm@vger.kernel.org, varkabhadram@gmail.com, Kamil Debski Subject: [PATCH v5] hwmon: pwm-fan: Add pwm-fan driver Date: Wed, 16 Jul 2014 17:46:42 +0200 Message-id: <1405525602-30563-1-git-send-email-k.debski@samsung.com> X-Mailer: git-send-email 1.7.9.5 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuplluLIzCtJLcpLzFFi42I5/e+xoG7OvGPBBt/W8VnMP3KO1eLH6wts Fpd3zWGzuHt3FaPFk4VnmCzuTNvLZrH2yF12i/UzXrNYHDjwl9HiZMccRgcujyunTrN77Jx1 l93jwcTdbB47vzewe/RtWcXo8XmTXABbFJdNSmpOZllqkb5dAlfG16Wr2QreeVUcPOjYwPjE pouRk0NCwERi3sfPLBC2mMSFe+vZQGwhgemMEhcm5HQxcgHZHUwS/+/+Y+5i5OBgE9CUWHXP A6RGRCBS4mvfDhaQGmaBrYwSix99BxskLGAm8ej7SUYQm0VAVeLA+0vMIDavgItE95XHrCBz JAQUJOZMspnAyL2AkWEVo2hqQXJBcVJ6rpFecWJucWleul5yfu4mRnAgPZPewbiqweIQowAH oxIPb0LrsWAh1sSy4srcQ4wSHMxKIrzTZgGFeFMSK6tSi/Lji0pzUosPMUpzsCiJ8x5stQ4U EkhPLEnNTk0tSC2CyTJxcEo1MBqkTo/5MU13Wp7NizdOL94pcXz/VXvSw3GjIIPv9tQ36gf/ 7qh+d/2ZnLbvsW3x4QEmLwx0Ut79/3j59AS+tOWJqS1LWQ4pdNjXGuybP7fslsmD/sezxBau em9nedxMfPfEk8371u9atkxBdrH1nZZdHlmzdi0J+Pk3fPOs+RdlBLIfnf72KLpAiaU4I9FQ i7moOBEATEa/JSACAAA= Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org The pwm-fan driver enables control of fans connected to PWM lines. This driver uses the PWM framework, so it is compatible with all PWM devices that provide drivers through the PWM framework. Signed-off-by: Kamil Debski Reviewed-by: Varka Bhadram Reviewed-by: Tobias Klauser --- Changes since v4: - remove unused variables from pwm_fan_ctx - fixes in the set_pwm function Changes since v3: - fix missing "\n" in error messages - remove of_match_ptr which was not necessary - change error returned in case of failed allocation to -ENOMEM Changes since v2: - add CONFIG_PM_SLEEP around pwm_fan_suspend and pwm_fan_resume Changes since v1: - added documentation to Documentation/hwmon - fix checkpatch errors - added extra description to Kconfig - removed whitespace errors - include files rearranged to be in alphabetical order - remove unused sysfs entry pwm1_enable - changed the behavior of the set_pwm function - when 0 PWM value is set pwm_disable is run - pwm_config return value is checked for errors - use of ATTRIBUTE_GROUPS was added - removed "Not enouch memory" error message - fixed probe return value in case of devm_of_pwm_get error - changed hwmon_device_register_with_groups to devm_hwmon_device_register_with_groups - changes suspend/resume to use pwm_disable/enable - removed unnecessary CONFIG_PM_SLEEP ifdefs --- .../devicetree/bindings/hwmon/pwm-fan.txt | 12 ++ Documentation/hwmon/pwm-fan | 17 ++ drivers/hwmon/Kconfig | 11 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/pwm-fan.c | 195 ++++++++++++++++++++ 5 files changed, 236 insertions(+) create mode 100644 Documentation/devicetree/bindings/hwmon/pwm-fan.txt create mode 100644 Documentation/hwmon/pwm-fan create mode 100644 drivers/hwmon/pwm-fan.c diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt new file mode 100644 index 0000000..610757c --- /dev/null +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt @@ -0,0 +1,12 @@ +Bindings for a fan connected to the PWM lines + +Required properties: +- compatible : "pwm-fan" +- pwms : the PWM that is used to control the PWM fan + +Example: + pwm-fan { + compatible = "pwm-fan"; + status = "okay"; + pwms = <&pwm 0 10000 0>; + }; diff --git a/Documentation/hwmon/pwm-fan b/Documentation/hwmon/pwm-fan new file mode 100644 index 0000000..18529d2 --- /dev/null +++ b/Documentation/hwmon/pwm-fan @@ -0,0 +1,17 @@ +Kernel driver pwm-fan +===================== + +This driver enables the use of a PWM module to drive a fan. It uses the +generic PWM interface thus it is hardware independent. It can be used on +many SoCs, as long as the SoC supplies a PWM line driver that exposes +the generic PWM API. + +Author: Kamil Debski + +Description +----------- + +The driver implements a simple interface for driving a fan connected to +a PWM output. It uses the generic PWM interface, thus it can be used with +a range of SoCs. The driver exposes the fan to the user space through +the hwmon's sysfs interface. diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 02d3d85..4ac13ab 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1105,6 +1105,17 @@ config SENSORS_PCF8591 source drivers/hwmon/pmbus/Kconfig +config SENSORS_PWM_FAN + tristate "PWM fan" + depends on PWM + help + If you say yes here you get support for fans connected to PWM lines. + The driver uses the generic PWM interface, thus it will work on a + variety of SoCs. + + This driver can also be built as a module. If so, the module + will be called pwm-fan. + config SENSORS_SHT15 tristate "Sensiron humidity and temperature sensors. SHT15 and compat." depends on GPIOLIB diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 3dc0f02..3967ecf 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -120,6 +120,7 @@ obj-$(CONFIG_SENSORS_NTC_THERMISTOR) += ntc_thermistor.o obj-$(CONFIG_SENSORS_PC87360) += pc87360.o obj-$(CONFIG_SENSORS_PC87427) += pc87427.o obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o +obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c new file mode 100644 index 0000000..63076d6 --- /dev/null +++ b/drivers/hwmon/pwm-fan.c @@ -0,0 +1,195 @@ +/* + * pwm-fan.c - Hwmon driver for fans connected to PWM lines. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * + * Author: Kamil Debski + * + * 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; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; 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 + +#define MAX_PWM 255 + +struct pwm_fan_ctx { + struct mutex lock; + struct pwm_device *pwm; + unsigned char pwm_value; +}; + +static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); + unsigned long pwm, duty; + ssize_t ret; + + if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) + return -EINVAL; + + mutex_lock(&ctx->lock); + + if (ctx->pwm_value == pwm) + goto exit_set_pwm_no_change; + + if (pwm == 0) { + pwm_disable(ctx->pwm); + goto exit_set_pwm; + } + + duty = DIV_ROUND_UP(pwm * (ctx->pwm->period - 1), MAX_PWM); + ret = pwm_config(ctx->pwm, duty, ctx->pwm->period); + if (ret) + goto exit_set_pwm_err; + + if (ctx->pwm_value == 0) { + ret = pwm_enable(ctx->pwm); + if (ret) + goto exit_set_pwm_err; + } + +exit_set_pwm: + ctx->pwm_value = pwm; +exit_set_pwm_no_change: + ret = count; +exit_set_pwm_err: + mutex_unlock(&ctx->lock); + return ret; +} + +static ssize_t show_pwm(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); + + return sprintf(buf, "%u\n", ctx->pwm_value); +} + + +static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0); + +static struct attribute *pwm_fan_attrs[] = { + &sensor_dev_attr_pwm1.dev_attr.attr, + NULL, +}; + +ATTRIBUTE_GROUPS(pwm_fan); + +static int pwm_fan_probe(struct platform_device *pdev) +{ + struct device *hwmon; + struct pwm_fan_ctx *ctx; + int duty_cycle; + int ret; + + ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + mutex_init(&ctx->lock); + + ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, 0); + if (IS_ERR(ctx->pwm)) { + dev_err(&pdev->dev, "Could not get PWM\n"); + return PTR_ERR(ctx->pwm); + } + + dev_set_drvdata(&pdev->dev, ctx); + platform_set_drvdata(pdev, ctx); + + /* Set duty cycle to maximum allowed */ + duty_cycle = ctx->pwm->period - 1; + ctx->pwm_value = MAX_PWM; + + ret = pwm_config(ctx->pwm, duty_cycle, ctx->pwm->period); + if (ret) { + dev_err(&pdev->dev, "Failed to configure PWM\n"); + return ret; + } + + /* Enbale PWM output */ + ret = pwm_enable(ctx->pwm); + if (ret) { + dev_err(&pdev->dev, "Failed to enable PWM\n"); + return ret; + } + + hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, + "pwmfan", ctx, + pwm_fan_groups); + if (IS_ERR(hwmon)) { + dev_err(&pdev->dev, "Failed to register hwmon device\n"); + pwm_disable(ctx->pwm); + return PTR_ERR(hwmon); + } + return 0; +} + +static int pwm_fan_remove(struct platform_device *pdev) +{ + struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); + + if (ctx->pwm_value) + pwm_disable(ctx->pwm); + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int pwm_fan_suspend(struct device *dev) +{ + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); + + if (ctx->pwm_value) + pwm_disable(ctx->pwm); + return 0; +} + +static int pwm_fan_resume(struct device *dev) +{ + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); + + if (ctx->pwm_value) + return pwm_enable(ctx->pwm); + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); + +static struct of_device_id of_pwm_fan_match[] = { + { .compatible = "pwm-fan", }, + {}, +}; + +static struct platform_driver pwm_fan_driver = { + .probe = pwm_fan_probe, + .remove = pwm_fan_remove, + .driver = { + .name = "pwm-fan", + .pm = &pwm_fan_pm, + .of_match_table = of_pwm_fan_match, + }, +}; + +module_platform_driver(pwm_fan_driver); + +MODULE_AUTHOR("Kamil Debski "); +MODULE_ALIAS("platform:pwm-fan"); +MODULE_DESCRIPTION("PWM FAN driver"); +MODULE_LICENSE("GPL");