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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018, STMicroelectronics - All Rights Reserved
* Author(s): Patrice Chotard, <patrice.chotard@foss.st.com> for STMicroelectronics.
*/
#include <common.h>
#include <linux/clk.h>
#include <clock.h>
#include <init.h>
#include <io.h>
/* Timer control1 register */
#define CR1_CEN BIT(0)
#define CR1_ARPE BIT(7)
/* Event Generation Register register */
#define EGR_UG BIT(0)
/* Auto reload register for free running config */
#define GPT_FREE_RUNNING 0xFFFFFFFF
#define MHZ_1 1000000
struct stm32_timer_regs {
u32 cr1;
u32 cr2;
u32 smcr;
u32 dier;
u32 sr;
u32 egr;
u32 ccmr1;
u32 ccmr2;
u32 ccer;
u32 cnt;
u32 psc;
u32 arr;
u32 reserved;
u32 ccr1;
u32 ccr2;
u32 ccr3;
u32 ccr4;
u32 reserved1;
u32 dcr;
u32 dmar;
u32 tim2_5_or;
};
static struct stm32_timer_regs *timer_base;
static u64 stm32_timer_read(void)
{
return readl(&timer_base->cnt);
}
/* A bit obvious isn't it? */
static struct clocksource cs = {
.read = stm32_timer_read,
.mask = CLOCKSOURCE_MASK(32),
.shift = 0,
.priority = 100,
};
static int stm32_timer_probe(struct device *dev)
{
struct resource *iores;
struct clk *clk;
u32 rate, psc;
int ret;
iores = dev_request_mem_resource(dev, 0);
if (IS_ERR(iores))
return PTR_ERR(iores);
timer_base = IOMEM(iores->start);
clk = clk_get(dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
ret = clk_enable(clk);
if (ret)
return ret;
/* Stop the timer */
clrbits_le32(&timer_base->cr1, CR1_CEN);
/* get timer clock */
rate = clk_get_rate(clk);
/* we set timer prescaler to obtain a 1MHz timer counter frequency */
psc = (rate / MHZ_1) - 1;
writel(psc, &timer_base->psc);
/* Configure timer for auto-reload */
setbits_le32(&timer_base->cr1, CR1_ARPE);
/* load value for auto reload */
writel(GPT_FREE_RUNNING, &timer_base->arr);
/* start timer */
setbits_le32(&timer_base->cr1, CR1_CEN);
/* Update generation */
setbits_le32(&timer_base->egr, EGR_UG);
cs.mult = clocksource_hz2mult(MHZ_1, cs.shift);
return init_clock(&cs);
}
static struct of_device_id stm32_timer_dt_ids[] = {
{ .compatible = "st,stm32-timer" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, stm32_timer_dt_ids);
static struct driver stm32_timer_driver = {
.name = "stm32-timer",
.probe = stm32_timer_probe,
.of_compatible = stm32_timer_dt_ids,
};
postcore_platform_driver(stm32_timer_driver);
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