linux/drivers/watchdog/meson_gxbb_wdt.c
Guenter Roeck 1678f83095 watchdog: meson_gxbb_wdt: Convert to use device managed functions and other improvements
Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.
Other improvements as listed below.

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

- Drop assignments to otherwise unused variables
- Drop unnecessary braces around conditional return statements
- Drop empty remove function
- Use devm_add_action_or_reset() for calls to clk_disable_unprepare
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device
- Replace shutdown function with call to watchdog_stop_on_reboot()

Cc: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:23 +02:00

207 lines
5.2 KiB
C

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright (c) 2016 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
*
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define DEFAULT_TIMEOUT 30 /* seconds */
#define GXBB_WDT_CTRL_REG 0x0
#define GXBB_WDT_TCNT_REG 0x8
#define GXBB_WDT_RSET_REG 0xc
#define GXBB_WDT_CTRL_CLKDIV_EN BIT(25)
#define GXBB_WDT_CTRL_CLK_EN BIT(24)
#define GXBB_WDT_CTRL_EE_RESET BIT(21)
#define GXBB_WDT_CTRL_EN BIT(18)
#define GXBB_WDT_CTRL_DIV_MASK (BIT(18) - 1)
#define GXBB_WDT_TCNT_SETUP_MASK (BIT(16) - 1)
#define GXBB_WDT_TCNT_CNT_SHIFT 16
struct meson_gxbb_wdt {
void __iomem *reg_base;
struct watchdog_device wdt_dev;
struct clk *clk;
};
static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return 0;
}
static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return 0;
}
static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
writel(0, data->reg_base + GXBB_WDT_RSET_REG);
return 0;
}
static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
unsigned long tcnt = timeout * 1000;
if (tcnt > GXBB_WDT_TCNT_SETUP_MASK)
tcnt = GXBB_WDT_TCNT_SETUP_MASK;
wdt_dev->timeout = timeout;
meson_gxbb_wdt_ping(wdt_dev);
writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG);
return 0;
}
static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)
{
struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
unsigned long reg;
reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);
return ((reg >> GXBB_WDT_TCNT_CNT_SHIFT) -
(reg & GXBB_WDT_TCNT_SETUP_MASK)) / 1000;
}
static const struct watchdog_ops meson_gxbb_wdt_ops = {
.start = meson_gxbb_wdt_start,
.stop = meson_gxbb_wdt_stop,
.ping = meson_gxbb_wdt_ping,
.set_timeout = meson_gxbb_wdt_set_timeout,
.get_timeleft = meson_gxbb_wdt_get_timeleft,
};
static const struct watchdog_info meson_gxbb_wdt_info = {
.identity = "Meson GXBB Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)
{
struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
if (watchdog_active(&data->wdt_dev))
meson_gxbb_wdt_start(&data->wdt_dev);
return 0;
}
static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev)
{
struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
if (watchdog_active(&data->wdt_dev))
meson_gxbb_wdt_stop(&data->wdt_dev);
return 0;
}
static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)
};
static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {
{ .compatible = "amlogic,meson-gxbb-wdt", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);
static void meson_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int meson_gxbb_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct meson_gxbb_wdt *data;
int ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->reg_base))
return PTR_ERR(data->reg_base);
data->clk = devm_clk_get(dev, NULL);
if (IS_ERR(data->clk))
return PTR_ERR(data->clk);
ret = clk_prepare_enable(data->clk);
if (ret)
return ret;
ret = devm_add_action_or_reset(dev, meson_clk_disable_unprepare,
data->clk);
if (ret)
return ret;
platform_set_drvdata(pdev, data);
data->wdt_dev.parent = dev;
data->wdt_dev.info = &meson_gxbb_wdt_info;
data->wdt_dev.ops = &meson_gxbb_wdt_ops;
data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;
data->wdt_dev.min_timeout = 1;
data->wdt_dev.timeout = DEFAULT_TIMEOUT;
watchdog_set_drvdata(&data->wdt_dev, data);
/* Setup with 1ms timebase */
writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
GXBB_WDT_CTRL_EE_RESET |
GXBB_WDT_CTRL_CLK_EN |
GXBB_WDT_CTRL_CLKDIV_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
watchdog_stop_on_reboot(&data->wdt_dev);
return devm_watchdog_register_device(dev, &data->wdt_dev);
}
static struct platform_driver meson_gxbb_wdt_driver = {
.probe = meson_gxbb_wdt_probe,
.driver = {
.name = "meson-gxbb-wdt",
.pm = &meson_gxbb_wdt_pm_ops,
.of_match_table = meson_gxbb_wdt_dt_ids,
},
};
module_platform_driver(meson_gxbb_wdt_driver);
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
MODULE_LICENSE("Dual BSD/GPL");