This adds userspace consumer for common clock.
This driver is inspired from Userspace regulator consumer
(REGULATOR_USERSPACE_CONSUMER) and it is useful for test purposes and
some classes of devices that are controlled entirely from user space.
Example binding and usages:
clksqw_userspace_consumer {
compatible = "linux,clock-userspace-consumer";
clocks = <&clksqw>;
};
# cd /sys/devices/platform/clksqw_userspace_consumer
# echo 8192 > rate
# echo 1 > enable
This also create new COMMON_CLK_DEBUG option and this userspace clock
consumer depends on it.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
* v2
- change compatible property to "linux,clock-userspace-consumer"
- rename sysfs file from 'state' to 'enable'
- create new COMMON_CLK_DEBUG option
.../bindings/clock/clk-userspace-consumer.txt | 17 +++
drivers/clk/Kconfig | 9 ++
drivers/clk/Kconfig.debug | 9 ++
drivers/clk/Makefile | 1 +
drivers/clk/clk-userspace-consumer.c | 169 +++++++++++++++++++++
5 files changed, 205 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/clk-userspace-consumer.txt
create mode 100644 drivers/clk/Kconfig.debug
create mode 100644 drivers/clk/clk-userspace-consumer.c
diff --git a/Documentation/devicetree/bindings/clock/clk-userspace-consumer.txt b/Documentation/devicetree/bindings/clock/clk-userspace-consumer.txt
new file mode 100644
index 0000000..f513a40
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/clk-userspace-consumer.txt
@@ -0,0 +1,17 @@
+* Userspace consumer for common clock
+
+Required properties:
+- compatible: Should be "linux,clock-userspace-consumer"
+- clocks: clock phandle to control from userspace
+
+Examples:
+
+clk32k_userspace_consumer {
+ compatible = "linux,clock-userspace-consumer";
+ clocks = <&clk32k>;
+};
+
+sqw_userspace_consumer {
+ compatible = "linux,clock-userspace-consumer";
+ clocks = <&sqw>;
+};
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index eca8e01..d4b5184 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -25,6 +25,15 @@ config COMMON_CLK
menu "Common Clock Framework"
depends on COMMON_CLK
+config COMMON_CLK_DEBUG
+ bool "Clock driver debugging support"
+ depends on DEBUG_KERNEL
+ ---help---
+ Say Y here if you are developing clock drivers or trying to
+ debug and identify the problems.
+
+source "drivers/clk/Kconfig.debug"
+
config COMMON_CLK_WM831X
tristate "Clock driver for WM831x/2x PMICs"
depends on MFD_WM831X
diff --git a/drivers/clk/Kconfig.debug b/drivers/clk/Kconfig.debug
new file mode 100644
index 0000000..01a7ed4
--- /dev/null
+++ b/drivers/clk/Kconfig.debug
@@ -0,0 +1,9 @@
+config COMMON_CLK_USERSPACE_CONSUMER
+ tristate "Userspace clock consumer support"
+ depends on COMMON_CLK_DEBUG
+ help
+ There are some classes of devices that are controlled entirely
+ from user space. Userspace consumer driver provides ability to
+ control clock for such devices.
+
+ If unsure, say no.
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index b038e36..f3b51f1 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-gpio.o
ifeq ($(CONFIG_OF), y)
obj-$(CONFIG_COMMON_CLK) += clk-conf.o
endif
+obj-$(CONFIG_COMMON_CLK_USERSPACE_CONSUMER) += clk-userspace-consumer.o
# hardware specific clock types
# please keep this section sorted lexicographically by file/directory path name
diff --git a/drivers/clk/clk-userspace-consumer.c b/drivers/clk/clk-userspace-consumer.c
new file mode 100644
index 0000000..846665a
--- /dev/null
+++ b/drivers/clk/clk-userspace-consumer.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2016 Akinobu Mita <akinobu.mita@xxxxxxxxx>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Inspired from reg-userspace-consumer
+ */
+
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+
+struct clk_userspace_consumer {
+ struct mutex lock;
+ bool enabled;
+ struct clk *clk;
+};
+
+static ssize_t clk_show_enable(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct clk_userspace_consumer *consumer = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", consumer->enabled);
+}
+
+static ssize_t clk_store_enable(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ struct clk_userspace_consumer *consumer = dev_get_drvdata(dev);
+ bool enabled;
+ int ret;
+
+ ret = strtobool(buf, &enabled);
+ if (ret)
+ return ret;
+
+ mutex_lock(&consumer->lock);
+
+ if (enabled != consumer->enabled) {
+ int ret = 0;
+
+ if (enabled) {
+ ret = clk_prepare_enable(consumer->clk);
+ if (ret) {
+ dev_err(dev, "Failed to configure state: %d\n",
+ ret);
+ }
+ } else {
+ clk_disable_unprepare(consumer->clk);
+ }
+
+ if (!ret)
+ consumer->enabled = enabled;
+ }
+
+ mutex_unlock(&consumer->lock);
+
+ return count;
+}
+static DEVICE_ATTR(enable, 0644, clk_show_enable, clk_store_enable);
+
+static ssize_t clk_show_rate(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct clk_userspace_consumer *consumer = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%ld\n", clk_get_rate(consumer->clk));
+}
+
+static ssize_t clk_store_rate(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct clk_userspace_consumer *consumer = dev_get_drvdata(dev);
+ unsigned long rate;
+ int err;
+
+ err = kstrtoul(buf, 0, &rate);
+ if (err)
+ return err;
+
+ err = clk_set_rate(consumer->clk, rate);
+ if (err)
+ return err;
+
+ return count;
+}
+static DEVICE_ATTR(rate, 0644, clk_show_rate, clk_store_rate);
+
+static struct attribute *attributes[] = {
+ &dev_attr_enable.attr,
+ &dev_attr_rate.attr,
+ NULL,
+};
+
+static const struct attribute_group attr_group = {
+ .attrs = attributes,
+};
+
+static int clk_userspace_consumer_probe(struct platform_device *pdev)
+{
+ struct clk_userspace_consumer *consumer;
+ int ret;
+
+ consumer = devm_kzalloc(&pdev->dev, sizeof(*consumer), GFP_KERNEL);
+ if (!consumer)
+ return -ENOMEM;
+
+ mutex_init(&consumer->lock);
+
+ consumer->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(consumer->clk)) {
+ ret = PTR_ERR(consumer->clk);
+ dev_err(&pdev->dev, "Failed to get clock: %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, consumer);
+
+ ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int clk_userspace_consumer_remove(struct platform_device *pdev)
+{
+ struct clk_userspace_consumer *consumer = platform_get_drvdata(pdev);
+
+ sysfs_remove_group(&pdev->dev.kobj, &attr_group);
+
+ mutex_lock(&consumer->lock);
+ if (consumer->enabled)
+ clk_disable_unprepare(consumer->clk);
+ mutex_unlock(&consumer->lock);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+
+static const struct of_device_id userspace_consumer_id[] = {
+ { .compatible = "linux,clock-userspace-consumer" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, userspace_consumer_id);
+
+#endif
+
+static struct platform_driver clk_userspace_consumer_driver = {
+ .probe = clk_userspace_consumer_probe,
+ .remove = clk_userspace_consumer_remove,
+ .driver = {
+ .name = "clk-userspace-consumer",
+ .of_match_table = of_match_ptr(userspace_consumer_id),
+ },
+};
+module_platform_driver(clk_userspace_consumer_driver);
+
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@xxxxxxxxx>");
+MODULE_DESCRIPTION("Userspace consumer for common clock");
+MODULE_LICENSE("GPL");
--
2.5.0
--
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