Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757811Ab3EJRo7 (ORCPT ); Fri, 10 May 2013 13:44:59 -0400 Received: from zetta.elopez.com.ar ([199.30.59.35]:36535 "EHLO zetta.elopez.com.ar" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755812Ab3EJRoz (ORCPT ); Fri, 10 May 2013 13:44:55 -0400 Message-ID: <518D320C.4010707@elopez.com.ar> Date: Fri, 10 May 2013 14:44:44 -0300 From: =?UTF-8?B?RW1pbGlvIEzDs3Bleg==?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130428 Thunderbird/17.0.5 MIME-Version: 1.0 To: Soren Brinkmann CC: Mike Turquette , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH RFC] clk: Introduce userspace clock driver References: <1368207091-32538-1-git-send-email-soren.brinkmann@xilinx.com> <1368207091-32538-2-git-send-email-soren.brinkmann@xilinx.com> In-Reply-To: <1368207091-32538-2-git-send-email-soren.brinkmann@xilinx.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7406 Lines: 250 Hi, El 10/05/13 14:31, Soren Brinkmann escribió: > The userspace clock driver can be used to expose clock controls through > sysfs to userspace. The driver creates entries in /sys/class/clk. > > Signed-off-by: Soren Brinkmann > --- > .../devicetree/bindings/clock/clk-userspace.txt | 7 + > drivers/clk/Kconfig | 9 ++ > drivers/clk/Makefile | 1 + > drivers/clk/clk-userspace.c | 169 +++++++++++++++++++++ > 4 files changed, 186 insertions(+) > create mode 100644 Documentation/devicetree/bindings/clock/clk-userspace.txt > create mode 100644 drivers/clk/clk-userspace.c > > diff --git a/Documentation/devicetree/bindings/clock/clk-userspace.txt b/Documentation/devicetree/bindings/clock/clk-userspace.txt > new file mode 100644 > index 0000000..2d153c7 > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/clk-userspace.txt > @@ -0,0 +1,7 @@ > + > +Example: > + usclk: usclk { > + compatible = "clk-userspace"; > + clocks = <&foo 15>, <&bar>; > + clock-count = <2>; > + }; Does this belong on DT? It isn't describing hardware, is it? > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig > index 0357ac4..b35b62c 100644 > --- a/drivers/clk/Kconfig > +++ b/drivers/clk/Kconfig > @@ -81,6 +81,15 @@ config COMMON_CLK_AXI_CLKGEN > Support for the Analog Devices axi-clkgen pcore clock generator for Xilinx > FPGAs. It is commonly used in Analog Devices' reference designs. > > +config COMMON_CLK_USERSPACE > + bool "Userspace Clock Controls" > + depends on OF > + depends on SYSFS > + help > + ---help--- > + Expose clock controls through sysfs to userspace. Clocks are selected > + through the device tree and the controls are exposed in > + /sys/class/clk. > endmenu > > source "drivers/clk/mvebu/Kconfig" > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile > index fa435bc..f2f68c8 100644 > --- a/drivers/clk/Makefile > +++ b/drivers/clk/Makefile > @@ -8,6 +8,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-fixed-rate.o > obj-$(CONFIG_COMMON_CLK) += clk-gate.o > obj-$(CONFIG_COMMON_CLK) += clk-mux.o > obj-$(CONFIG_COMMON_CLK) += clk-composite.o > +obj-$(CONFIG_COMMON_CLK_USERSPACE) += clk-userspace.o > > # SoCs specific > obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o > diff --git a/drivers/clk/clk-userspace.c b/drivers/clk/clk-userspace.c > new file mode 100644 > index 0000000..931cf92 > --- /dev/null > +++ b/drivers/clk/clk-userspace.c > @@ -0,0 +1,169 @@ > +/* > + * Userspace clock driver > + * > + * Copyright (C) 2013 Xilinx > + * > + * Sören Brinkmann > + * > + * This program is free software: you can redistribute it and/or modify > + * it under the terms of the GNU General Public License v2 as published by > + * the Free Software Foundation. > + * > + * 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. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see . > + * > + * Expose clock controls through sysfs to userspace. > + * > + * By writing 0/1 to 'enable' the clock can be disabled/enabled. Reading > + * that file returns the current state - 0 = disabled, 1 = enabled. > + * > + * Reading 'set_rate' returns the current clock frequency in Hz. Writing > + * the file requests setting a new frequency in Hz. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define DRIVER_NAME "clk-userspace" > + > +struct usclk_data { > + struct clk *clk; > + int enabled; > +}; > + > +static ssize_t enable_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct usclk_data *pdata = dev_get_drvdata(dev); > + > + return scnprintf(buf, PAGE_SIZE, "%u\n", pdata->enabled); > +} > + > +static ssize_t enable_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + unsigned long enable; > + int ret; > + struct usclk_data *pdata = dev_get_drvdata(dev); > + > + ret = kstrtoul(buf, 0, &enable); > + if (ret) > + return -EINVAL; > + > + enable = !!enable; > + if (enable == pdata->enabled) > + return count; > + > + if (enable) > + ret = clk_prepare_enable(pdata->clk); > + else > + clk_disable_unprepare(pdata->clk); > + > + if (ret) > + return -EBUSY; > + > + pdata->enabled = enable; > + return count; > +} > + > +static DEVICE_ATTR(enable, 0644, enable_show, enable_store); > + > +static ssize_t set_rate_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct usclk_data *pdata = dev_get_drvdata(dev); > + > + return scnprintf(buf, PAGE_SIZE, "%lu\n", clk_get_rate(pdata->clk)); > +} > + > +static ssize_t set_rate_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + int ret = 0; > + unsigned long rate; > + struct usclk_data *pdata = dev_get_drvdata(dev); > + > + ret = kstrtoul(buf, 0, &rate); > + if (ret) > + return -EINVAL; > + > + rate = clk_round_rate(pdata->clk, rate); > + ret = clk_set_rate(pdata->clk, rate); > + if (ret) > + return -EBUSY; > + > + return count; > +} > + > +static DEVICE_ATTR(set_rate, 0644, set_rate_show, set_rate_store); > + > +static const struct attribute *usclk_attrs[] = { > + &dev_attr_enable.attr, > + &dev_attr_set_rate.attr, > + NULL > +}; For debugging purposes, being able to change parents would be nice too. Maybe this belongs to debugfs instead of sysfs though. > + > +static const struct attribute_group usclk_attr_grp = { > + .attrs = (struct attribute **)usclk_attrs, > +}; > + > +static int usclk_setup(void) > +{ > + int ret; > + int i; > + struct usclk_data *pdata; > + u32 clock_count; > + struct class *clk_class; > + struct device *dev; > + struct device_node *np = of_find_compatible_node(NULL, NULL, > + "clk-userspace"); > + > + ret = of_property_read_u32(np, "clock-count", &clock_count); > + if (ret || !clock_count) > + return ret; > + > + pdata = kzalloc(clock_count * sizeof(*pdata), GFP_KERNEL); > + if (!pdata) > + return -ENOMEM; > + > + clk_class = class_create(THIS_MODULE, "clk"); > + if (!clk_class) { > + pr_err("unable to create class\n"); > + goto err_free; > + } > + > + for (i = 0; i < clock_count; i++) { > + pdata[i].clk = of_clk_get(np, i); > + if (IS_ERR(pdata[i].clk)) { > + pr_warn("input clock #%u not found\n", i); > + continue; > + } > + > + dev = device_create(clk_class, NULL, MKDEV(0, 0), NULL, > + of_clk_get_parent_name(np, i)); > + if (!dev) { > + pr_warn("unable to create device #%d\n", i); > + continue; > + } > + > + dev_set_drvdata(dev, &pdata[i]); > + sysfs_create_group(&dev->kobj, &usclk_attr_grp); > + } > + > + return 0; > + > +err_free: > + kfree(pdata); > + > + return ret; > +} > +late_initcall(usclk_setup); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/