From patchwork Tue Jul 15 11:51:32 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamil Debski X-Patchwork-Id: 369974 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 77922140170 for ; Tue, 15 Jul 2014 21:52:21 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758321AbaGOLwF (ORCPT ); Tue, 15 Jul 2014 07:52:05 -0400 Received: from mailout1.samsung.com ([203.254.224.24]:29346 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758516AbaGOLv7 (ORCPT ); Tue, 15 Jul 2014 07:51:59 -0400 Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0N8R00B884YKNKE0@mailout1.samsung.com>; Tue, 15 Jul 2014 20:51:56 +0900 (KST) X-AuditID: cbfee61b-f79f86d00000144c-b1-53c515dce7e8 Received: from epmmp2 ( [203.254.227.17]) by epcpsbgm2.samsung.com (EPCPMTA) with SMTP id 32.1D.05196.CD515C35; Tue, 15 Jul 2014 20:51:56 +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 <0N8R00AIK4XXHZ30@mmp2.samsung.com>; Tue, 15 Jul 2014 20:51:56 +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, Kamil Debski Subject: [PATCH v3] hwmon: pwm-fan: Add pwm-fan driver Date: Tue, 15 Jul 2014 13:51:32 +0200 Message-id: <1405425092-553-1-git-send-email-k.debski@samsung.com> X-Mailer: git-send-email 1.7.9.5 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpmluLIzCtJLcpLzFFi42I5/e+xoO4d0aPBBk1nDCzmHznHavHj9QU2 i8u75rBZ3L27itHiycIzTBZ3pu1ls1h75C67xfoZr1ksDhz4y+jA6XHl1Gl2jwcTd7N57Pze wO7Rt2UVo8fnTXIBrFFcNimpOZllqUX6dglcGXMX6xXM8Kw4/mYrcwPjWusuRk4OCQETiSdv VzJD2GISF+6tZ+ti5OIQEpjOKDH3zEUmCKeDSaL79zqWLkYODjYBTYlV9zxAGkQEIiW+9u1g AbGZBeYySizeJA1iCwuYSZyYuYIdxGYRUJX4NeUcWA2vgJPE4/PTmEHGSAgoSMyZZDOBkXsB I8MqRtHUguSC4qT0XCO94sTc4tK8dL3k/NxNjOCgeSa9g3FVg8UhRgEORiUeXol3h4OFWBPL iitzDzFKcDArifDW/zsSLMSbklhZlVqUH19UmpNafIhRmoNFSZz3YKt1oJBAemJJanZqakFq EUyWiYNTqoHR/pVX68pEefM/hpd8OgvS18nLrTb5nM1z4sFM6e7voszf1Vb3fVbL8nS7sixc aevkdZ61tQUffbNtH5zgiVt3e4OC4uu1B/vYNxvz1l24s1t0zY/rW09MU5GVmLqvfPuiy96l Kwu0/5n3pz5Z4nw5o3fu8Tl2Yf1NL/c2H50ULFO7R2pRIPNxJZbijERDLeai4kQAi3v7UhYC AAA= 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 --- 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 | 201 ++++++++++++++++++++ 5 files changed, 242 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..f534607 --- /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..03d45f2 --- /dev/null +++ b/drivers/hwmon/pwm-fan.c @@ -0,0 +1,201 @@ +/* + * 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 device *hwmon; + struct mutex lock; + struct platform_device *pdev; + struct pwm_device *pwm; + unsigned int duty_cycle; + 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; + int ret; + + if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) + return -EINVAL; + + mutex_lock(&ctx->lock); + + if (ctx->pwm_value == pwm) + goto exit_set_pwm; + + if (pwm == 0) { + pwm_disable(ctx->pwm); + ctx->pwm_value = 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) { + count = ret; /* Set the return value */ + goto exit_set_pwm; + } + + if (ctx->pwm_value == 0) + ret = pwm_enable(ctx->pwm); + if (ret) { + count = ret; /* Set the return value */ + goto exit_set_pwm; + } + + ctx->duty_cycle = duty; + ctx->pwm_value = pwm; + +exit_set_pwm: + mutex_unlock(&ctx->lock); + return count; +} + +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 pwm_fan_ctx *ctx; + int ret; + + ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return PTR_ERR(ctx); + + ctx->pdev = pdev; + 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"); + return PTR_ERR(ctx->pwm); + } + + dev_set_drvdata(&pdev->dev, ctx); + platform_set_drvdata(pdev, ctx); + + /* Set duty cycle to maximum allowed */ + ctx->duty_cycle = ctx->pwm->period - 1; + ctx->pwm_value = MAX_PWM; + + ret = pwm_config(ctx->pwm, ctx->duty_cycle, ctx->pwm->period); + if (ret) { + dev_err(&pdev->dev, "Failed to configure PWM"); + return ret; + } + + /* Enbale PWM output */ + ret = pwm_enable(ctx->pwm); + if (ret) { + dev_err(&pdev->dev, "Failed to enable PWM"); + return ret; + } + + ctx->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, + "pwmfan", ctx, pwm_fan_groups); + + if (IS_ERR(ctx->hwmon)) { + dev_err(&pdev->dev, "Failed to register hwmon device"); + pwm_disable(ctx->pwm); + return PTR_ERR(ctx->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_match_ptr(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");