u-boot/drivers/watchdog/at91sam9_wdt.c
Simon Glass 8b85dfc675 dm: Avoid accessing seq directly
At present various drivers etc. access the device's 'seq' member directly.
This makes it harder to change the meaning of that member. Change access
to go through a function instead.

The drivers/i2c/lpc32xx_i2c.c file is left unchanged for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-18 20:32:21 -07:00

124 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* [origin: Linux kernel drivers/watchdog/at91sam9_wdt.c]
*
* Watchdog driver for AT91SAM9x processors.
*
* Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
* Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
*/
/*
* The Watchdog Timer Mode Register can be only written to once. If the
* timeout need to be set from U-Boot, be sure that the bootstrap doesn't
* write to this register. Inform Linux to it too
*/
#include <log.h>
#include <asm/io.h>
#include <asm/arch/at91_wdt.h>
#include <common.h>
#include <div64.h>
#include <dm.h>
#include <errno.h>
#include <wdt.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
* use this to convert a watchdog
* value from seconds.
*/
#define WDT_SEC2TICKS(s) (((s) << 8) - 1)
/*
* Set the watchdog time interval in 1/256Hz (write-once)
* Counter is 12 bit.
*/
static int at91_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
struct at91_wdt_priv *priv = dev_get_priv(dev);
u64 timeout;
u32 ticks;
/* Calculate timeout in seconds and the resulting ticks */
timeout = timeout_ms;
do_div(timeout, 1000);
timeout = min_t(u64, timeout, WDT_MAX_TIMEOUT);
ticks = WDT_SEC2TICKS(timeout);
/* Check if disabled */
if (readl(priv->regs + AT91_WDT_MR) & AT91_WDT_MR_WDDIS) {
printf("sorry, watchdog is disabled\n");
return -1;
}
/*
* All counting occurs at SLOW_CLOCK / 128 = 256 Hz
*
* Since WDV is a 12-bit counter, the maximum period is
* 4096 / 256 = 16 seconds.
*/
priv->regval = AT91_WDT_MR_WDRSTEN /* causes watchdog reset */
| AT91_WDT_MR_WDDBGHLT /* disabled in debug mode */
| AT91_WDT_MR_WDD(0xfff) /* restart at any time */
| AT91_WDT_MR_WDV(ticks); /* timer value */
writel(priv->regval, priv->regs + AT91_WDT_MR);
return 0;
}
static int at91_wdt_stop(struct udevice *dev)
{
struct at91_wdt_priv *priv = dev_get_priv(dev);
/* Disable Watchdog Timer */
priv->regval |= AT91_WDT_MR_WDDIS;
writel(priv->regval, priv->regs + AT91_WDT_MR);
return 0;
}
static int at91_wdt_reset(struct udevice *dev)
{
struct at91_wdt_priv *priv = dev_get_priv(dev);
writel(AT91_WDT_CR_WDRSTT | AT91_WDT_CR_KEY, priv->regs + AT91_WDT_CR);
return 0;
}
static const struct wdt_ops at91_wdt_ops = {
.start = at91_wdt_start,
.stop = at91_wdt_stop,
.reset = at91_wdt_reset,
};
static const struct udevice_id at91_wdt_ids[] = {
{ .compatible = "atmel,at91sam9260-wdt" },
{}
};
static int at91_wdt_probe(struct udevice *dev)
{
struct at91_wdt_priv *priv = dev_get_priv(dev);
priv->regs = dev_remap_addr(dev);
if (!priv->regs)
return -EINVAL;
debug("%s: Probing wdt%u\n", __func__, dev_seq(dev));
return 0;
}
U_BOOT_DRIVER(atmel_at91sam9260_wdt) = {
.name = "atmel_at91sam9260_wdt",
.id = UCLASS_WDT,
.of_match = at91_wdt_ids,
.priv_auto = sizeof(struct at91_wdt_priv),
.ops = &at91_wdt_ops,
.probe = at91_wdt_probe,
};