This driver adds a DT test clock consumer that exposes debugfs files to enable/disable and set/get rate of the attached programmable clock. During development of a i2c-attached clock generator I found it useful to debug the clock generator's internal pll settings by enforcing clock rates through debugfs.
Signed-off-by: Sebastian Hesselbarth <[email protected]> --- Cc: Grant Likely <[email protected]> Cc: Rob Herring <[email protected]> Cc: Rob Landley <[email protected]> Cc: Mike Turquette <[email protected]> Cc: Linus Walleij <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Andrew Morton <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] --- .../bindings/clock/test-clock-consumer.txt | 19 ++ drivers/clk/Kconfig | 6 + drivers/clk/Makefile | 3 + drivers/clk/clk-test.c | 183 ++++++++++++++++++++ 4 files changed, 211 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/test-clock-consumer.txt create mode 100644 drivers/clk/clk-test.c diff --git a/Documentation/devicetree/bindings/clock/test-clock-consumer.txt b/Documentation/devicetree/bindings/clock/test-clock-consumer.txt new file mode 100644 index 0000000..3e228ed --- /dev/null +++ b/Documentation/devicetree/bindings/clock/test-clock-consumer.txt @@ -0,0 +1,19 @@ +* Test Clock Consumer + +The test clock consumer allows to debug clock providers by exposing +debugfs files to enable/disable and set/get rate of attached clock +respectively. It is especially useful for checking programmable clock +generators, e.g. enforcing target clock rates to debug clock generator's +pll settings. Currently, there is only one clock per test clock consumer +supported but more than one test clock consumer can be added. + +Required properties: +- compatible : shall be "test-clock-consumer" +- clocks : phandle of the clock to debug + +Example: + +clock-consumer { + compatible = "test-clock-consumer"; + clocks = <&programmable_clock>; +}; diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index a47e6ee..e23e471 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -33,6 +33,12 @@ config COMMON_CLK_DEBUG clk_flags, clk_prepare_count, clk_enable_count & clk_notifier_count. +config COMMON_CLK_TEST_CONSUMER + tristate "Clock consumer test driver" + ---help--- + This is a clock consumer test driver to allow testing clock + provider through user space. + config COMMON_CLK_WM831X tristate "Clock driver for WM831x/2x PMICs" depends on MFD_WM831X diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 300d477..095899e 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -34,3 +34,6 @@ obj-$(CONFIG_X86) += x86/ obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o + +# Debug drivers +obj-$(CONFIG_COMMON_CLK_TEST_CONSUMER) += clk-test.o diff --git a/drivers/clk/clk-test.c b/drivers/clk/clk-test.c new file mode 100644 index 0000000..08dd66b --- /dev/null +++ b/drivers/clk/clk-test.c @@ -0,0 +1,183 @@ +/* + * clk-test.c: Common Clock Framework Test Clock Consumer + * + * (c) 2012 Sebastian Hesselbarth <[email protected]> + * + * 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. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/debugfs.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/of_platform.h> + +struct clock_consumer_data { + struct clk *clk; + struct dentry *clkdir; + const char *name; + unsigned int enabled; +}; + +static struct dentry *rootdir; + +static int clock_consumer_debug_rate_set(void *data, u64 val) +{ + struct clock_consumer_data *ccdata = (struct clock_consumer_data *)data; + + if (!ccdata->enabled) + return -EBUSY; + + return clk_set_rate(ccdata->clk, (unsigned long)val); +} + +static int clock_consumer_debug_rate_get(void *data, u64 *val) +{ + struct clock_consumer_data *ccdata = (struct clock_consumer_data *)data; + + if (!ccdata->enabled) + return -EBUSY; + + *val = clk_get_rate(ccdata->clk); + + return 0; +} + +static int clock_consumer_debug_enable_set(void *data, u64 val) +{ + struct clock_consumer_data *ccdata = (struct clock_consumer_data *)data; + + if ((val == ccdata->enabled) || (!val && !ccdata->enabled)) + return 0; + + ccdata->enabled = (val) ? 1 : 0; + + if (ccdata->enabled) + return clk_prepare_enable(ccdata->clk); + + clk_disable_unprepare(ccdata->clk); + return 0; +} + +static int clock_consumer_debug_enable_get(void *data, u64 *val) +{ + struct clock_consumer_data *ccdata = (struct clock_consumer_data *)data; + *val = ccdata->enabled; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(clock_consumer_debug_ops_enable, + clock_consumer_debug_enable_get, + clock_consumer_debug_enable_set, "%llu\n"); +DEFINE_SIMPLE_ATTRIBUTE(clock_consumer_debug_ops_rate, + clock_consumer_debug_rate_get, + clock_consumer_debug_rate_set, "%llu\n"); + +static int clock_consumer_debug_create_one(struct platform_device *pdev) +{ + struct clock_consumer_data *ccdata = platform_get_drvdata(pdev); + struct dentry *d; + + if (!rootdir) { + rootdir = debugfs_create_dir("clk_consumer", NULL); + if (WARN_ON(IS_ERR_OR_NULL(rootdir))) + return -ENOMEM; + } + + ccdata->clkdir = debugfs_create_dir(ccdata->name, rootdir); + if (WARN_ON(IS_ERR_OR_NULL(ccdata->clkdir))) + return -ENOMEM; + + d = debugfs_create_file("enable", S_IRUGO | S_IWUGO, ccdata->clkdir, + ccdata, &clock_consumer_debug_ops_enable); + if (WARN_ON(IS_ERR_OR_NULL(d))) + goto err_out; + + d = debugfs_create_file("rate", S_IRUGO | S_IWUGO, ccdata->clkdir, + ccdata, &clock_consumer_debug_ops_rate); + if (WARN_ON(IS_ERR_OR_NULL(d))) + goto err_out; + + return 0; + +err_out: + debugfs_remove(ccdata->clkdir); + return -ENOMEM; +} + +static struct of_device_id clock_consumer_of_match[] = { + { .compatible = "test-clock-consumer", }, + { } +}; + +static int clock_consumer_probe(struct platform_device *pdev) +{ + struct clock_consumer_data *ccdata; + int ret; + + ccdata = devm_kzalloc(&pdev->dev, sizeof(struct clock_consumer_data), + GFP_KERNEL); + if (WARN_ON(!ccdata)) + return -ENOMEM; + + ccdata->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(ccdata->clk)) { + dev_err(&pdev->dev, "unable to get parent clock"); + return PTR_RET(ccdata->clk); + } + + platform_set_drvdata(pdev, ccdata); + ccdata->name = pdev->dev.of_node->name; + + ret = clock_consumer_debug_create_one(pdev); + if (ret) + return ret; + + dev_info(&pdev->dev, "installed clock consumer %s\n", + ccdata->name); + + return 0; +} + +static int clock_consumer_remove(struct platform_device *pdev) +{ + struct clock_consumer_data *ccdata = platform_get_drvdata(pdev); + + if (!ccdata || !ccdata->clkdir) + return 0; + + debugfs_remove_recursive(ccdata->clkdir); + if (!IS_ERR(ccdata->clk) && ccdata->enabled) + clk_disable_unprepare(ccdata->clk); + + dev_info(&pdev->dev, "removed clock consumer %s\n", ccdata->name); + + if (rootdir && list_empty(&rootdir->d_subdirs)) + debugfs_remove_recursive(rootdir); + + platform_set_drvdata(pdev, NULL); + + return 0; +} + +static struct platform_driver clock_consumer_driver = { + .driver = { + .name = "clock-consumer", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(clock_consumer_of_match), + }, + .probe = clock_consumer_probe, + .remove = clock_consumer_remove, +}; + +module_platform_driver(clock_consumer_driver); + +MODULE_AUTHOR("Sebastian Hesselbarth <[email protected]>"); +MODULE_DESCRIPTION("Common clock framwork test clock consumer driver"); +MODULE_LICENSE("GPL v2"); -- 1.7.10.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
