Re: [PATCH] clk: add generic driver for fixed rate clock
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2015-11-17 15:46:32
Also in:
linux-clk, lkml
Hi Stefan, (quoting the full driver, as it predates linux-clk) On Sun, Sep 1, 2013 at 6:40 AM, Stefan Kristiansson [off-list ref] wrote:
This adds a simple driver with the only purpose to initialise the fixed rate clock. This is useful for systems that do not wish to use seperate init code for the fixed rate clock init, but rather only rely on a device tree description of it. Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Thanks, this is still very useful! I stumbled across this old patch while trying to instantiate a fixed rate clock from a DT overlay. Without this, the clock is never instantiated, as drivers/clk/clk-fixed-rate.c uses CLK_OF_DECLARE() :-( With your driver, it works as expected (after fixing the modpost complaint, cfr. below). However, I think that instead of creating a new driver, you should just add the meat of clk-generic-fixed.c to clk-fixed-rate.c.
quoted hunk
--- drivers/clk/Kconfig | 8 ++++++ drivers/clk/Makefile | 1 + drivers/clk/clk-generic-fixed.c | 59 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 68 insertions(+) create mode 100644 drivers/clk/clk-generic-fixed.cdiff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index 51380d6..7c8ea78 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig@@ -87,6 +87,14 @@ config CLK_PPC_CORENET This adds the clock driver support for Freescale PowerPC corenet platforms using common clock framework. +config COMMON_CLK_GENERIC_FIXED + tristate "Generic fixed rate clock driver" + depends on OF + ---help--- + Driver for systems that do not want to register their fixed rate + clocks through init code, but rather through the device tree + description. + endmenu source "drivers/clk/mvebu/Kconfig"diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 4038c2b..2d46647 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-$(CONFIG_COMMON_CLK_GENERIC_FIXED) += clk-generic-fixed.o # SoCs specific obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.odiff --git a/drivers/clk/clk-generic-fixed.c b/drivers/clk/clk-generic-fixed.c new file mode 100644 index 0000000..85df8a8 --- /dev/null +++ b/drivers/clk/clk-generic-fixed.c@@ -0,0 +1,59 @@ +/* + * Copyright 2013 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Generic driver for fixed rate clock + */ +#include <linux/platform_device.h> +#include <linux/clk-provider.h> +#include <linux/clk.h> +#include <linux/of.h> +#include <linux/module.h> + +static const struct of_device_id generic_fixed_clk_match[] __initconst = {
Please drop the __initconst, as it causes a section mismatch.
+ { .compatible = "fixed-clock",},
+ {}
+};
+
+static int generic_fixed_clk_probe(struct platform_device *pdev)
+{
+ of_fixed_clk_setup(pdev->dev.of_node);
+
+ return 0;
+}
+
+static int generic_fixed_clk_remove(struct platform_device *pdev)
+{
+ of_clk_del_provider(pdev->dev.of_node);
+
+ return 0;
+}
+
+static struct platform_driver generic_fixed_clk_driver = {
+ .driver = {
+ .name = "generic-fixed-clk",
+ .owner = THIS_MODULE,
+ .of_match_table = generic_fixed_clk_match,
+ },
+ .probe = generic_fixed_clk_probe,
+ .remove = generic_fixed_clk_remove,
+};
+
+static int __init generic_fixed_clk_init(void)
+{
+ return platform_driver_register(&generic_fixed_clk_driver);
+}
+subsys_initcall(generic_fixed_clk_init);
+
+static void __exit generic_fixed_exit(void)
+{
+ platform_driver_unregister(&generic_fixed_clk_driver);
+}
+module_exit(generic_fixed_exit);
+
+MODULE_AUTHOR("Stefan Kristiansson [off-list ref]");
+MODULE_DESCRIPTION("Generic driver for fixed rate clock");
+MODULE_LICENSE("GPL v2");
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds