2012-10-18 19:42:39 +00:00
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/*
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* Author: Carlo Caione <carlo@carlocaione.org>
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*
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* Based on clocksource for nomadik
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <common.h>
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#include <clock.h>
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#include <io.h>
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#include <init.h>
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#include <driver.h>
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#include <errno.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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/* Registers */
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#define ST_CLO 0x04
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static __iomem void *stc_base;
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static uint64_t stc_read_cycles(void)
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{
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return readl(stc_base + ST_CLO);
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}
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static struct clocksource bcm2835_stc = {
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.read = stc_read_cycles,
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.mask = CLOCKSOURCE_MASK(32),
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};
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static int bcm2835_cs_probe(struct device_d *dev)
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{
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static struct clk *stc_clk;
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u32 rate;
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int ret;
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stc_clk = clk_get(dev, NULL);
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if (IS_ERR(stc_clk)) {
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ret = PTR_ERR(stc_clk);
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dev_err(dev, "clock not found: %d\n", ret);
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return ret;
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}
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ret = clk_enable(stc_clk);
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if (ret) {
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dev_err(dev, "clock failed to enable: %d\n", ret);
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clk_put(stc_clk);
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return ret;
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}
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rate = clk_get_rate(stc_clk);
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stc_base = dev_request_mem_region(dev, 0);
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clocks_calc_mult_shift(&bcm2835_stc.mult, &bcm2835_stc.shift, rate, NSEC_PER_SEC, 60);
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init_clock(&bcm2835_stc);
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return 0;
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}
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static __maybe_unused struct of_device_id bcm2835_cs_dt_ids[] = {
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{
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.compatible = "brcm,bcm2835-system-timer",
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}, {
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/* sentinel */
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}
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};
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static struct driver_d bcm2835_cs_driver = {
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.name = "bcm2835-cs",
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.probe = bcm2835_cs_probe,
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.of_compatible = DRV_OF_COMPAT(bcm2835_cs_dt_ids),
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};
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static int bcm2835_cs_init(void)
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{
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return platform_driver_register(&bcm2835_cs_driver);
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}
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2013-10-19 12:20:50 +00:00
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core_initcall(bcm2835_cs_init);
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