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Date: Fri, 1 Apr 2011 12:08:11 +0100
From: Jamie Iles <jamie@...ieiles.com>
To: linux-kernel@...r.kernel.org
Cc: johnstul@...ibm.com, tglx@...utronix.de,
jacob.jun.pan@...ux.intel.com, Jamie Iles <jamie@...ieiles.com>
Subject: [RFC PATCH 2/2] clocksource: platform driver for APB timers
Add a platform driver for the APB timers that can be used for embedded
systems such as ARM SoC. This uses early_platform so that the timers
can be used early in the boot sequence.
Cc: John Stultz <johnstul@...ibm.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Jamie Iles <jamie@...ieiles.com>
---
drivers/clocksource/Kconfig | 5 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/dw_apb_timer_platform.c | 173 +++++++++++++++++++++++++++
3 files changed, 179 insertions(+), 0 deletions(-)
create mode 100644 drivers/clocksource/dw_apb_timer_platform.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 09081ab..fa53da8 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -4,3 +4,8 @@
config DW_APB_TIMER
bool
+
+config DW_APB_TIMER_PLATFORM
+ depends on HAVE_CLK
+ select DW_APB_TIMER
+ bool
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index c3785c3..9e2de99 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o
obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o
obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o
obj-$(CONFIG_DW_APB_TIMER) += dw_apb_timer.o
+obj-$(CONFIG_DW_APB_TIMER_PLATFORM) += dw_apb_timer_platform.o
diff --git a/drivers/clocksource/dw_apb_timer_platform.c b/drivers/clocksource/dw_apb_timer_platform.c
new file mode 100644
index 0000000..22b5fcd
--- /dev/null
+++ b/drivers/clocksource/dw_apb_timer_platform.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2011 Picochip Ltd., Jamie Iles
+ *
+ * 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.
+ *
+ * Platform driver support for Synopsys DesignWare APB timers.
+ */
+#include <linux/clk.h>
+#include <linux/dw_apb_timer.h>
+#include <linux/err.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+static int dw_apb_event_probe(struct platform_device *pdev, int irq)
+{
+ int err;
+ struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ struct dw_apb_clock_event_device *dwclk;
+ void __iomem *base;
+ struct clk *clk;
+
+ if (!request_mem_region(mem->start, resource_size(mem),
+ "dw_apb_timer"))
+ return -ENOMEM;
+
+ base = ioremap(mem->start, resource_size(mem));
+ if (!base) {
+ dev_err(&pdev->dev, "failed to remap i/o memory\n");
+ err = -ENOMEM;
+ goto out_release_mem;
+ }
+
+ clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "no clk\n");
+ err = PTR_ERR(clk);
+ goto out_unmap;
+ }
+
+ err = clk_enable(clk);
+ if (err) {
+ dev_err(&pdev->dev, "failed to enable clk\n");
+ goto out_put_clk;
+ }
+
+ dwclk = dw_apb_clockevent_init(0, "dw_apb_timer_plat0", 300, base,
+ irq, clk_get_rate(clk));
+ if (!dwclk) {
+ err = -ENODEV;
+ goto out_disable_clk;
+ }
+
+ dw_apb_clockevent_register(dwclk);
+
+ return 0;
+
+out_disable_clk:
+ clk_disable(clk);
+out_put_clk:
+ clk_put(clk);
+out_unmap:
+ iounmap(base);
+out_release_mem:
+ release_mem_region(mem->start, resource_size(mem));
+
+ return err;
+}
+
+static int dw_apb_source_probe(struct platform_device *pdev)
+{
+ struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ int err;
+ void __iomem *base;
+ struct clk *clk;
+ struct dw_apb_clocksource *dwclk;
+
+ if (!request_mem_region(mem->start, resource_size(mem),
+ "dw_apb_timer"))
+ return -ENOMEM;
+
+ base = ioremap(mem->start, resource_size(mem));
+ if (!base) {
+ dev_err(&pdev->dev, "failed to remap i/o memory\n");
+ err = -ENOMEM;
+ goto out_release_mem;
+ }
+
+ clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "no clk\n");
+ err = PTR_ERR(clk);
+ goto out_unmap;
+ }
+
+ err = clk_enable(clk);
+ if (err) {
+ dev_err(&pdev->dev, "failed to enable clk\n");
+ goto out_put_clk;
+ }
+
+ dwclk = dw_apb_clocksource_init(300, "dw_apb_plat0", base,
+ clk_get_rate(clk));
+ if (!dwclk) {
+ err = -ENODEV;
+ goto out_disable_clk;
+ }
+ dw_apb_clocksource_start(dwclk);
+ dw_apb_clocksource_register(dwclk);
+
+ return 0;
+
+out_disable_clk:
+ clk_disable(clk);
+out_put_clk:
+ clk_put(clk);
+out_unmap:
+ iounmap(base);
+out_release_mem:
+ release_mem_region(mem->start, resource_size(mem));
+
+ return err;
+}
+
+static int __devinit dw_apb_timer_probe(struct platform_device *pdev)
+{
+ int irq = platform_get_irq(pdev, 0);
+
+ /*
+ * If the timer has an interrupt defined then we use it as a
+ * clockevents device otherwise we use it as a clocksource device.
+ */
+ return irq >= 0 ? dw_apb_event_probe(pdev, irq) :
+ dw_apb_source_probe(pdev);
+}
+
+static int __devexit dw_apb_timer_remove(struct platform_device *pdev)
+{
+ return -EBUSY;
+}
+
+static struct platform_driver dw_apb_timer_driver = {
+ .probe = dw_apb_timer_probe,
+ .remove = __devexit_p(dw_apb_timer_remove),
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "dw_apb_timer",
+ },
+};
+early_platform_init("earlytimer", &dw_apb_timer_driver);
+
+
+static int __init dw_apb_timers_init(void)
+{
+ return platform_driver_register(&dw_apb_timer_driver);
+}
+module_init(dw_apb_timers_init);
+
+static void __exit dw_apb_timers_exit(void)
+{
+ platform_driver_unregister(&dw_apb_timer_driver);
+}
+module_exit(dw_apb_timers_exit);
+
+MODULE_AUTHOR("Jamie Iles");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Timer driver for Synopsys DesignWare APB timers");
--
1.7.4
--
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