linux-stable/drivers/watchdog/rza_wdt.c
Guenter Roeck 2361ac5289 watchdog: rza_wdt: Use 'dev' instead of dereferencing it repeatedly
Introduce local variable 'struct device *dev' and use it instead of
dereferencing it repeatedly.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:27 +02:00

247 lines
6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Renesas RZ/A Series WDT Driver
*
* Copyright (C) 2017 Renesas Electronics America, Inc.
* Copyright (C) 2017 Chris Brandt
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define DEFAULT_TIMEOUT 30
/* Watchdog Timer Registers */
#define WTCSR 0
#define WTCSR_MAGIC 0xA500
#define WTSCR_WT BIT(6)
#define WTSCR_TME BIT(5)
#define WTSCR_CKS(i) (i)
#define WTCNT 2
#define WTCNT_MAGIC 0x5A00
#define WRCSR 4
#define WRCSR_MAGIC 0x5A00
#define WRCSR_RSTE BIT(6)
#define WRCSR_CLEAR_WOVF 0xA500 /* special value */
/* The maximum CKS register setting value to get the longest timeout */
#define CKS_3BIT 0x7
#define CKS_4BIT 0xF
#define DIVIDER_3BIT 16384 /* Clock divider when CKS = 0x7 */
#define DIVIDER_4BIT 4194304 /* Clock divider when CKS = 0xF */
struct rza_wdt {
struct watchdog_device wdev;
void __iomem *base;
struct clk *clk;
u8 count;
u8 cks;
};
static void rza_wdt_calc_timeout(struct rza_wdt *priv, int timeout)
{
unsigned long rate = clk_get_rate(priv->clk);
unsigned int ticks;
if (priv->cks == CKS_4BIT) {
ticks = DIV_ROUND_UP(timeout * rate, DIVIDER_4BIT);
/*
* Since max_timeout was set in probe, we know that the timeout
* value passed will never calculate to a tick value greater
* than 256.
*/
priv->count = 256 - ticks;
} else {
/* Start timer with longest timeout */
priv->count = 0;
}
pr_debug("%s: timeout set to %u (WTCNT=%d)\n", __func__,
timeout, priv->count);
}
static int rza_wdt_start(struct watchdog_device *wdev)
{
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
/* Stop timer */
writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
/* Must dummy read WRCSR:WOVF at least once before clearing */
readb(priv->base + WRCSR);
writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
rza_wdt_calc_timeout(priv, wdev->timeout);
writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME |
WTSCR_CKS(priv->cks), priv->base + WTCSR);
return 0;
}
static int rza_wdt_stop(struct watchdog_device *wdev)
{
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
return 0;
}
static int rza_wdt_ping(struct watchdog_device *wdev)
{
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
pr_debug("%s: timeout = %u\n", __func__, wdev->timeout);
return 0;
}
static int rza_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
{
wdev->timeout = timeout;
rza_wdt_start(wdev);
return 0;
}
static int rza_wdt_restart(struct watchdog_device *wdev, unsigned long action,
void *data)
{
struct rza_wdt *priv = watchdog_get_drvdata(wdev);
/* Stop timer */
writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
/* Must dummy read WRCSR:WOVF at least once before clearing */
readb(priv->base + WRCSR);
writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
/*
* Start timer with fastest clock source and only 1 clock left before
* overflow with reset option enabled.
*/
writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
writew(WTCNT_MAGIC | 255, priv->base + WTCNT);
writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME, priv->base + WTCSR);
/*
* Actually make sure the above sequence hits hardware before sleeping.
*/
wmb();
/* Wait for WDT overflow (reset) */
udelay(20);
return 0;
}
static const struct watchdog_info rza_wdt_ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
.identity = "Renesas RZ/A WDT Watchdog",
};
static const struct watchdog_ops rza_wdt_ops = {
.owner = THIS_MODULE,
.start = rza_wdt_start,
.stop = rza_wdt_stop,
.ping = rza_wdt_ping,
.set_timeout = rza_set_timeout,
.restart = rza_wdt_restart,
};
static int rza_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rza_wdt *priv;
unsigned long rate;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->clk = devm_clk_get(dev, NULL);
if (IS_ERR(priv->clk))
return PTR_ERR(priv->clk);
rate = clk_get_rate(priv->clk);
if (rate < 16384) {
dev_err(dev, "invalid clock rate (%ld)\n", rate);
return -ENOENT;
}
priv->wdev.info = &rza_wdt_ident,
priv->wdev.ops = &rza_wdt_ops,
priv->wdev.parent = dev;
priv->cks = (u8)(uintptr_t) of_device_get_match_data(dev);
if (priv->cks == CKS_4BIT) {
/* Assume slowest clock rate possible (CKS=0xF) */
priv->wdev.max_timeout = (DIVIDER_4BIT * U8_MAX) / rate;
} else if (priv->cks == CKS_3BIT) {
/* Assume slowest clock rate possible (CKS=7) */
rate /= DIVIDER_3BIT;
/*
* Since the max possible timeout of our 8-bit count
* register is less than a second, we must use
* max_hw_heartbeat_ms.
*/
priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX) / rate;
dev_dbg(dev, "max hw timeout of %dms\n",
priv->wdev.max_hw_heartbeat_ms);
}
priv->wdev.min_timeout = 1;
priv->wdev.timeout = DEFAULT_TIMEOUT;
watchdog_init_timeout(&priv->wdev, 0, dev);
watchdog_set_drvdata(&priv->wdev, priv);
ret = devm_watchdog_register_device(dev, &priv->wdev);
if (ret)
dev_err(dev, "Cannot register watchdog device\n");
return ret;
}
static const struct of_device_id rza_wdt_of_match[] = {
{ .compatible = "renesas,r7s9210-wdt", .data = (void *)CKS_4BIT, },
{ .compatible = "renesas,rza-wdt", .data = (void *)CKS_3BIT, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rza_wdt_of_match);
static struct platform_driver rza_wdt_driver = {
.probe = rza_wdt_probe,
.driver = {
.name = "rza_wdt",
.of_match_table = rza_wdt_of_match,
},
};
module_platform_driver(rza_wdt_driver);
MODULE_DESCRIPTION("Renesas RZ/A WDT Driver");
MODULE_AUTHOR("Chris Brandt <chris.brandt@renesas.com>");
MODULE_LICENSE("GPL v2");