stm32_timer.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018, STMicroelectronics - All Rights Reserved
* Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <fdtdec.h>
#include <timer.h>
#include <asm/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
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;
};
struct stm32_timer_priv {
struct stm32_timer_regs *base;
};
static int stm32_timer_get_count(struct udevice *dev, u64 *count)
{
struct stm32_timer_priv *priv = dev_get_priv(dev);
struct stm32_timer_regs *regs = priv->base;
*count = readl(®s->cnt);
return 0;
}
static int stm32_timer_probe(struct udevice *dev)
{
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
struct stm32_timer_priv *priv = dev_get_priv(dev);
struct stm32_timer_regs *regs;
struct clk clk;
fdt_addr_t addr;
int ret;
u32 rate, psc;
addr = dev_read_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
priv->base = (struct stm32_timer_regs *)addr;
ret = clk_get_by_index(dev, 0, &clk);
if (ret < 0)
return ret;
ret = clk_enable(&clk);
if (ret) {
dev_err(dev, "failed to enable clock\n");
return ret;
}
regs = priv->base;
/* Stop the timer */
clrbits_le32(®s->cr1, CR1_CEN);
/* get timer clock */
rate = clk_get_rate(&clk);
/* we set timer prescaler to obtain a 1MHz timer counter frequency */
psc = (rate / CONFIG_SYS_HZ_CLOCK) - 1;
writel(psc, ®s->psc);
/* Set timer frequency to 1MHz */
uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
/* Configure timer for auto-reload */
setbits_le32(®s->cr1, CR1_ARPE);
/* load value for auto reload */
writel(GPT_FREE_RUNNING, ®s->arr);
/* start timer */
setbits_le32(®s->cr1, CR1_CEN);
/* Update generation */
setbits_le32(®s->egr, EGR_UG);
return 0;
}
static const struct timer_ops stm32_timer_ops = {
.get_count = stm32_timer_get_count,
};
static const struct udevice_id stm32_timer_ids[] = {
{ .compatible = "st,stm32-timer" },
{}
};
U_BOOT_DRIVER(stm32_timer) = {
.name = "stm32_timer",
.id = UCLASS_TIMER,
.of_match = stm32_timer_ids,
.priv_auto_alloc_size = sizeof(struct stm32_timer_priv),
.probe = stm32_timer_probe,
.ops = &stm32_timer_ops,
};