e2146d8650
In order to increase the compilation test coverage, add the COMPILE_TEST so the driver can be compiled even if it does not belong to the platform or the architecture. The io.h header inclusion is also added as it the driver does not compile on UM platform. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
87 lines
1.8 KiB
C
87 lines
1.8 KiB
C
/*
|
|
* Copyright (C) Maxime Coquelin 2015
|
|
* Author: Maxime Coquelin <mcoquelin.stm32@gmail.com>
|
|
* License terms: GNU General Public License (GPL), version 2
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/clocksource.h>
|
|
#include <linux/clockchips.h>
|
|
#include <linux/io.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_address.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/bitops.h>
|
|
|
|
#define SYST_CSR 0x00
|
|
#define SYST_RVR 0x04
|
|
#define SYST_CVR 0x08
|
|
#define SYST_CALIB 0x0c
|
|
|
|
#define SYST_CSR_ENABLE BIT(0)
|
|
|
|
#define SYSTICK_LOAD_RELOAD_MASK 0x00FFFFFF
|
|
|
|
static int __init system_timer_of_register(struct device_node *np)
|
|
{
|
|
struct clk *clk = NULL;
|
|
void __iomem *base;
|
|
u32 rate;
|
|
int ret;
|
|
|
|
base = of_iomap(np, 0);
|
|
if (!base) {
|
|
pr_warn("system-timer: invalid base address\n");
|
|
return -ENXIO;
|
|
}
|
|
|
|
ret = of_property_read_u32(np, "clock-frequency", &rate);
|
|
if (ret) {
|
|
clk = of_clk_get(np, 0);
|
|
if (IS_ERR(clk)) {
|
|
ret = PTR_ERR(clk);
|
|
goto out_unmap;
|
|
}
|
|
|
|
ret = clk_prepare_enable(clk);
|
|
if (ret)
|
|
goto out_clk_put;
|
|
|
|
rate = clk_get_rate(clk);
|
|
if (!rate) {
|
|
ret = -EINVAL;
|
|
goto out_clk_disable;
|
|
}
|
|
}
|
|
|
|
writel_relaxed(SYSTICK_LOAD_RELOAD_MASK, base + SYST_RVR);
|
|
writel_relaxed(SYST_CSR_ENABLE, base + SYST_CSR);
|
|
|
|
ret = clocksource_mmio_init(base + SYST_CVR, "arm_system_timer", rate,
|
|
200, 24, clocksource_mmio_readl_down);
|
|
if (ret) {
|
|
pr_err("failed to init clocksource (%d)\n", ret);
|
|
if (clk)
|
|
goto out_clk_disable;
|
|
else
|
|
goto out_unmap;
|
|
}
|
|
|
|
pr_info("ARM System timer initialized as clocksource\n");
|
|
|
|
return 0;
|
|
|
|
out_clk_disable:
|
|
clk_disable_unprepare(clk);
|
|
out_clk_put:
|
|
clk_put(clk);
|
|
out_unmap:
|
|
iounmap(base);
|
|
pr_warn("ARM System timer register failed (%d)\n", ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
CLOCKSOURCE_OF_DECLARE(arm_systick, "arm,armv7m-systick",
|
|
system_timer_of_register);
|