91 lines
2.0 KiB
C
91 lines
2.0 KiB
C
/*
|
|
* 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)
|
|
{
|
|
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);
|
|
stc_base = dev_request_mem_region(dev, 0);
|
|
|
|
clocks_calc_mult_shift(&bcm2835_stc.mult, &bcm2835_stc.shift, rate, NSEC_PER_SEC, 60);
|
|
init_clock(&bcm2835_stc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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);
|