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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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28804c2c8f
The STPMIC1 PMIC embeds a watchdog which is disabled by default. As soon as the watchdog is started, it must be refreshed periodically otherwise the PMIC goes off. Signed-off-by: Pascal Paillet <p.paillet@st.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Lee Jones <lee.jones@linaro.org>
140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) STMicroelectronics 2018
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// Author: Pascal Paillet <p.paillet@st.com> for STMicroelectronics.
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#include <linux/kernel.h>
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#include <linux/mfd/stpmic1.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/of.h>
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#include <linux/regmap.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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/* WATCHDOG CONTROL REGISTER bit */
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#define WDT_START BIT(0)
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#define WDT_PING BIT(1)
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#define WDT_START_MASK BIT(0)
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#define WDT_PING_MASK BIT(1)
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#define WDT_STOP 0
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#define PMIC_WDT_MIN_TIMEOUT 1
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#define PMIC_WDT_MAX_TIMEOUT 256
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#define PMIC_WDT_DEFAULT_TIMEOUT 30
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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struct stpmic1_wdt {
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struct stpmic1 *pmic;
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struct watchdog_device wdtdev;
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};
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static int pmic_wdt_start(struct watchdog_device *wdd)
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{
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struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
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return regmap_update_bits(wdt->pmic->regmap,
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WCHDG_CR, WDT_START_MASK, WDT_START);
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}
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static int pmic_wdt_stop(struct watchdog_device *wdd)
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{
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struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
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return regmap_update_bits(wdt->pmic->regmap,
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WCHDG_CR, WDT_START_MASK, WDT_STOP);
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}
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static int pmic_wdt_ping(struct watchdog_device *wdd)
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{
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struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
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return regmap_update_bits(wdt->pmic->regmap,
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WCHDG_CR, WDT_PING_MASK, WDT_PING);
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}
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static int pmic_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
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wdd->timeout = timeout;
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/* timeout is equal to register value + 1 */
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return regmap_write(wdt->pmic->regmap, WCHDG_TIMER_CR, timeout - 1);
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}
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static const struct watchdog_info pmic_watchdog_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "STPMIC1 PMIC Watchdog",
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};
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static const struct watchdog_ops pmic_watchdog_ops = {
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.owner = THIS_MODULE,
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.start = pmic_wdt_start,
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.stop = pmic_wdt_stop,
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.ping = pmic_wdt_ping,
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.set_timeout = pmic_wdt_set_timeout,
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};
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static int pmic_wdt_probe(struct platform_device *pdev)
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{
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int ret;
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struct stpmic1 *pmic;
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struct stpmic1_wdt *wdt;
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if (!pdev->dev.parent)
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return -EINVAL;
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pmic = dev_get_drvdata(pdev->dev.parent);
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if (!pmic)
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return -EINVAL;
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wdt = devm_kzalloc(&pdev->dev, sizeof(struct stpmic1_wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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wdt->pmic = pmic;
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wdt->wdtdev.info = &pmic_watchdog_info;
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wdt->wdtdev.ops = &pmic_watchdog_ops;
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wdt->wdtdev.min_timeout = PMIC_WDT_MIN_TIMEOUT;
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wdt->wdtdev.max_timeout = PMIC_WDT_MAX_TIMEOUT;
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wdt->wdtdev.parent = &pdev->dev;
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wdt->wdtdev.timeout = PMIC_WDT_DEFAULT_TIMEOUT;
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watchdog_init_timeout(&wdt->wdtdev, 0, &pdev->dev);
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watchdog_set_nowayout(&wdt->wdtdev, nowayout);
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watchdog_set_drvdata(&wdt->wdtdev, wdt);
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ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
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if (ret)
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return ret;
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dev_dbg(wdt->pmic->dev, "PMIC Watchdog driver probed\n");
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return 0;
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}
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static const struct of_device_id of_pmic_wdt_match[] = {
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{ .compatible = "st,stpmic1-wdt" },
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{ },
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};
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MODULE_DEVICE_TABLE(of, of_pmic_wdt_match);
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static struct platform_driver stpmic1_wdt_driver = {
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.probe = pmic_wdt_probe,
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.driver = {
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.name = "stpmic1-wdt",
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.of_match_table = of_pmic_wdt_match,
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},
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};
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module_platform_driver(stpmic1_wdt_driver);
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MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
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MODULE_AUTHOR("Pascal Paillet <p.paillet@st.com>");
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MODULE_LICENSE("GPL v2");
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