Messages in this thread | | | Date | Fri, 10 May 2013 11:03:22 -0700 | From | Sören Brinkmann <> | Subject | Re: [PATCH RFC] clk: Introduce userspace clock driver |
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Hi Andy,
first, can you please send plain text email? The formatting gets messed up a bit for me otherwise.
On Fri, May 10, 2013 at 08:42:34PM +0300, Andy Shevchenko wrote: > 10.5.2013 20.32 "Soren Brinkmann" <soren.brinkmann@xilinx.com> kirjoitti: > > > > 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 <soren.brinkmann@xilinx.com> > > --- > > .../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>; > > + }; > > 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 <soren.brinkmann@xilinx.com> > > + * > > + * 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 > <http://www.gnu.org/licenses/>. > > + * > > + * 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 <linux/clk-provider.h> > > +#include <linux/fs.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/device.h> > > +#include <linux/slab.h> > > + > > +#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); > > strbool()? Can you explain this a little more, please? I grepped the kernel sources for 'strbool' and didn't get a single match.
Sören
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