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Release 4.14 drivers/watchdog/zx2967_wdt.c

Directory: drivers/watchdog
/*
 * watchdog driver for ZTE's zx2967 family
 *
 * Copyright (C) 2017 ZTE Ltd.
 *
 * Author: Baoyou Xie <baoyou.xie@linaro.org>
 *
 * License terms: GNU General Public License (GPL) version 2
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/watchdog.h>


#define ZX2967_WDT_CFG_REG			0x4

#define ZX2967_WDT_LOAD_REG			0x8

#define ZX2967_WDT_REFRESH_REG			0x18

#define ZX2967_WDT_START_REG			0x1c


#define ZX2967_WDT_REFRESH_MASK			GENMASK(5, 0)


#define ZX2967_WDT_CFG_DIV(n)			((((n) & 0xff) - 1) << 8)

#define ZX2967_WDT_START_EN			0x1

/*
 * Hardware magic number.
 * When watchdog reg is written, the lowest 16 bits are valid, but
 * the highest 16 bits should be always this number.
 */

#define ZX2967_WDT_WRITEKEY			(0x1234 << 16)

#define ZX2967_WDT_VAL_MASK			GENMASK(15, 0)


#define ZX2967_WDT_DIV_DEFAULT			16

#define ZX2967_WDT_DEFAULT_TIMEOUT		32

#define ZX2967_WDT_MIN_TIMEOUT			1

#define ZX2967_WDT_MAX_TIMEOUT			524

#define ZX2967_WDT_MAX_COUNT			0xffff


#define ZX2967_WDT_CLK_FREQ			0x8000


#define ZX2967_WDT_FLAG_REBOOT_MON		BIT(0)


struct zx2967_wdt {
	
struct watchdog_device	wdt_device;
	
void __iomem		*reg_base;
	
struct clk		*clock;
};


static inline u32 zx2967_wdt_readl(struct zx2967_wdt *wdt, u16 reg) { return readl_relaxed(wdt->reg_base + reg); }

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static inline void zx2967_wdt_writel(struct zx2967_wdt *wdt, u16 reg, u32 val) { writel_relaxed(val | ZX2967_WDT_WRITEKEY, wdt->reg_base + reg); }

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static void zx2967_wdt_refresh(struct zx2967_wdt *wdt) { u32 val; val = zx2967_wdt_readl(wdt, ZX2967_WDT_REFRESH_REG); /* * Bit 4-5, 1 and 2: refresh config info * Bit 2-3, 1 and 2: refresh counter * Bit 0-1, 1 and 2: refresh int-value * we shift each group value between 1 and 2 to refresh all data. */ val ^= ZX2967_WDT_REFRESH_MASK; zx2967_wdt_writel(wdt, ZX2967_WDT_REFRESH_REG, val & ZX2967_WDT_VAL_MASK); }

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static int zx2967_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); unsigned int divisor = ZX2967_WDT_DIV_DEFAULT; u32 count; count = timeout * ZX2967_WDT_CLK_FREQ; if (count > divisor * ZX2967_WDT_MAX_COUNT) divisor = DIV_ROUND_UP(count, ZX2967_WDT_MAX_COUNT); count = DIV_ROUND_UP(count, divisor); zx2967_wdt_writel(wdt, ZX2967_WDT_CFG_REG, ZX2967_WDT_CFG_DIV(divisor) & ZX2967_WDT_VAL_MASK); zx2967_wdt_writel(wdt, ZX2967_WDT_LOAD_REG, count & ZX2967_WDT_VAL_MASK); zx2967_wdt_refresh(wdt); wdd->timeout = (count * divisor) / ZX2967_WDT_CLK_FREQ; return 0; }

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static void __zx2967_wdt_start(struct zx2967_wdt *wdt) { u32 val; val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); val |= ZX2967_WDT_START_EN; zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val & ZX2967_WDT_VAL_MASK); }

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static void __zx2967_wdt_stop(struct zx2967_wdt *wdt) { u32 val; val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); val &= ~ZX2967_WDT_START_EN; zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val & ZX2967_WDT_VAL_MASK); }

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static int zx2967_wdt_start(struct watchdog_device *wdd) { struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); zx2967_wdt_set_timeout(wdd, wdd->timeout); __zx2967_wdt_start(wdt); return 0; }

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static int zx2967_wdt_stop(struct watchdog_device *wdd) { struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); __zx2967_wdt_stop(wdt); return 0; }

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static int zx2967_wdt_keepalive(struct watchdog_device *wdd) { struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); zx2967_wdt_refresh(wdt); return 0; }

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#define ZX2967_WDT_OPTIONS \ (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) static const struct watchdog_info zx2967_wdt_ident = { .options = ZX2967_WDT_OPTIONS, .identity = "zx2967 watchdog", }; static const struct watchdog_ops zx2967_wdt_ops = { .owner = THIS_MODULE, .start = zx2967_wdt_start, .stop = zx2967_wdt_stop, .ping = zx2967_wdt_keepalive, .set_timeout = zx2967_wdt_set_timeout, };
static void zx2967_wdt_reset_sysctrl(struct device *dev) { int ret; void __iomem *regmap; unsigned int offset, mask, config; struct of_phandle_args out_args; ret = of_parse_phandle_with_fixed_args(dev->of_node, "zte,wdt-reset-sysctrl", 3, 0, &out_args); if (ret) return; offset = out_args.args[0]; config = out_args.args[1]; mask = out_args.args[2]; regmap = syscon_node_to_regmap(out_args.np); if (IS_ERR(regmap)) { of_node_put(out_args.np); return; } regmap_update_bits(regmap, offset, mask, config); of_node_put(out_args.np); }

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static int zx2967_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct zx2967_wdt *wdt; struct resource *base; int ret; struct reset_control *rstc; wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; platform_set_drvdata(pdev, wdt); wdt->wdt_device.info = &zx2967_wdt_ident; wdt->wdt_device.ops = &zx2967_wdt_ops; wdt->wdt_device.timeout = ZX2967_WDT_DEFAULT_TIMEOUT; wdt->wdt_device.max_timeout = ZX2967_WDT_MAX_TIMEOUT; wdt->wdt_device.min_timeout = ZX2967_WDT_MIN_TIMEOUT; wdt->wdt_device.parent = &pdev->dev; base = platform_get_resource(pdev, IORESOURCE_MEM, 0); wdt->reg_base = devm_ioremap_resource(dev, base); if (IS_ERR(wdt->reg_base)) return PTR_ERR(wdt->reg_base); zx2967_wdt_reset_sysctrl(dev); wdt->clock = devm_clk_get(dev, NULL); if (IS_ERR(wdt->clock)) { dev_err(dev, "failed to find watchdog clock source\n"); return PTR_ERR(wdt->clock); } ret = clk_prepare_enable(wdt->clock); if (ret < 0) { dev_err(dev, "failed to enable clock\n"); return ret; } clk_set_rate(wdt->clock, ZX2967_WDT_CLK_FREQ); rstc = devm_reset_control_get_exclusive(dev, NULL); if (IS_ERR(rstc)) { dev_err(dev, "failed to get rstc"); ret = PTR_ERR(rstc); goto err; } reset_control_assert(rstc); reset_control_deassert(rstc); watchdog_set_drvdata(&wdt->wdt_device, wdt); watchdog_init_timeout(&wdt->wdt_device, ZX2967_WDT_DEFAULT_TIMEOUT, dev); watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT); ret = watchdog_register_device(&wdt->wdt_device); if (ret) goto err; dev_info(dev, "watchdog enabled (timeout=%d sec, nowayout=%d)", wdt->wdt_device.timeout, WATCHDOG_NOWAYOUT); return 0; err: clk_disable_unprepare(wdt->clock); return ret; }

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static int zx2967_wdt_remove(struct platform_device *pdev) { struct zx2967_wdt *wdt = platform_get_drvdata(pdev); watchdog_unregister_device(&wdt->wdt_device); clk_disable_unprepare(wdt->clock); return 0; }

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static const struct of_device_id zx2967_wdt_match[] = { { .compatible = "zte,zx296718-wdt", }, {} }; MODULE_DEVICE_TABLE(of, zx2967_wdt_match); static struct platform_driver zx2967_wdt_driver = { .probe = zx2967_wdt_probe, .remove = zx2967_wdt_remove, .driver = { .name = "zx2967-wdt", .of_match_table = of_match_ptr(zx2967_wdt_match), }, }; module_platform_driver(zx2967_wdt_driver); MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>"); MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver"); MODULE_LICENSE("GPL v2");

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Directory: drivers/watchdog
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