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/*
* Author: Carlo Caione <carlo@carlocaione.org>
*
* Based on clocksource for nomadik
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <common.h>
#include <clock.h>
#include <io.h>
#include <init.h>
#include <driver.h>
#include <errno.h>
#include <linux/clk.h>
#include <linux/err.h>
/* Registers */
#define ST_CLO 0x04
static __iomem void *stc_base;
static uint64_t stc_read_cycles(void)
{
return readl(stc_base + ST_CLO);
}
static struct clocksource bcm2835_stc = {
.read = stc_read_cycles,
.mask = CLOCKSOURCE_MASK(32),
};
static int bcm2835_cs_probe(struct device_d *dev)
{
struct resource *iores;
static struct clk *stc_clk;
u32 rate;
int ret;
stc_clk = clk_get(dev, NULL);
if (IS_ERR(stc_clk)) {
ret = PTR_ERR(stc_clk);
dev_err(dev, "clock not found: %d\n", ret);
return ret;
}
ret = clk_enable(stc_clk);
if (ret) {
dev_err(dev, "clock failed to enable: %d\n", ret);
clk_put(stc_clk);
return ret;
}
rate = clk_get_rate(stc_clk);
iores = dev_request_mem_resource(dev, 0);
if (IS_ERR(iores))
return PTR_ERR(iores);
stc_base = IOMEM(iores->start);
clocks_calc_mult_shift(&bcm2835_stc.mult, &bcm2835_stc.shift, rate, NSEC_PER_SEC, 60);
return init_clock(&bcm2835_stc);
}
static __maybe_unused struct of_device_id bcm2835_cs_dt_ids[] = {
{
.compatible = "brcm,bcm2835-system-timer",
}, {
/* sentinel */
}
};
static struct driver_d bcm2835_cs_driver = {
.name = "bcm2835-cs",
.probe = bcm2835_cs_probe,
.of_compatible = DRV_OF_COMPAT(bcm2835_cs_dt_ids),
};
static int bcm2835_cs_init(void)
{
return platform_driver_register(&bcm2835_cs_driver);
}
core_initcall(bcm2835_cs_init);
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