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![Uwe Kleine-König](/assets/img/avatar_default.png)
The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20230303213716.2123717-33-u.kleine-koenig@pengutronix.de Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
302 lines
6.8 KiB
C
302 lines
6.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* ST's LPC Watchdog
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*
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* Copyright (C) 2014 STMicroelectronics -- All Rights Reserved
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*
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* Author: David Paris <david.paris@st.com> for STMicroelectronics
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* Lee Jones <lee.jones@linaro.org> for STMicroelectronics
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*/
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#include <linux/clk.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include <linux/watchdog.h>
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#include <dt-bindings/mfd/st-lpc.h>
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/* Low Power Alarm */
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#define LPC_LPA_LSB_OFF 0x410
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#define LPC_LPA_START_OFF 0x418
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/* LPC as WDT */
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#define LPC_WDT_OFF 0x510
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static struct watchdog_device st_wdog_dev;
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struct st_wdog_syscfg {
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unsigned int reset_type_reg;
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unsigned int reset_type_mask;
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unsigned int enable_reg;
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unsigned int enable_mask;
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};
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struct st_wdog {
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void __iomem *base;
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struct device *dev;
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struct regmap *regmap;
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struct st_wdog_syscfg *syscfg;
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struct clk *clk;
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unsigned long clkrate;
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bool warm_reset;
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};
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static struct st_wdog_syscfg stih407_syscfg = {
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.enable_reg = 0x204,
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.enable_mask = BIT(19),
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};
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static const struct of_device_id st_wdog_match[] = {
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{
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.compatible = "st,stih407-lpc",
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.data = &stih407_syscfg,
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, st_wdog_match);
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static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
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{
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/* Type of watchdog reset - 0: Cold 1: Warm */
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if (st_wdog->syscfg->reset_type_reg)
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regmap_update_bits(st_wdog->regmap,
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st_wdog->syscfg->reset_type_reg,
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st_wdog->syscfg->reset_type_mask,
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st_wdog->warm_reset);
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/* Mask/unmask watchdog reset */
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regmap_update_bits(st_wdog->regmap,
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st_wdog->syscfg->enable_reg,
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st_wdog->syscfg->enable_mask,
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enable ? 0 : st_wdog->syscfg->enable_mask);
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}
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static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
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{
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unsigned long clkrate = st_wdog->clkrate;
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writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
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writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
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}
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static int st_wdog_start(struct watchdog_device *wdd)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
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writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);
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return 0;
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}
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static int st_wdog_stop(struct watchdog_device *wdd)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
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writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);
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return 0;
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}
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static int st_wdog_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
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wdd->timeout = timeout;
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st_wdog_load_timer(st_wdog, timeout);
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return 0;
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}
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static int st_wdog_keepalive(struct watchdog_device *wdd)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
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st_wdog_load_timer(st_wdog, wdd->timeout);
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return 0;
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}
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static const struct watchdog_info st_wdog_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "ST LPC WDT",
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};
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static const struct watchdog_ops st_wdog_ops = {
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.owner = THIS_MODULE,
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.start = st_wdog_start,
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.stop = st_wdog_stop,
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.ping = st_wdog_keepalive,
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.set_timeout = st_wdog_set_timeout,
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};
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static struct watchdog_device st_wdog_dev = {
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.info = &st_wdog_info,
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.ops = &st_wdog_ops,
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};
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static void st_clk_disable_unprepare(void *data)
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{
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clk_disable_unprepare(data);
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}
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static int st_wdog_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct of_device_id *match;
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struct device_node *np = dev->of_node;
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struct st_wdog *st_wdog;
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struct regmap *regmap;
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struct clk *clk;
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void __iomem *base;
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uint32_t mode;
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int ret;
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ret = of_property_read_u32(np, "st,lpc-mode", &mode);
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if (ret) {
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dev_err(dev, "An LPC mode must be provided\n");
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return -EINVAL;
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}
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/* LPC can either run as a Clocksource or in RTC or WDT mode */
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if (mode != ST_LPC_MODE_WDT)
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return -ENODEV;
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st_wdog = devm_kzalloc(dev, sizeof(*st_wdog), GFP_KERNEL);
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if (!st_wdog)
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return -ENOMEM;
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match = of_match_device(st_wdog_match, dev);
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if (!match) {
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dev_err(dev, "Couldn't match device\n");
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return -ENODEV;
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}
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st_wdog->syscfg = (struct st_wdog_syscfg *)match->data;
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base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(base))
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return PTR_ERR(base);
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regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
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if (IS_ERR(regmap)) {
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dev_err(dev, "No syscfg phandle specified\n");
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return PTR_ERR(regmap);
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}
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clk = devm_clk_get(dev, NULL);
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if (IS_ERR(clk)) {
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dev_err(dev, "Unable to request clock\n");
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return PTR_ERR(clk);
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}
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st_wdog->dev = dev;
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st_wdog->base = base;
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st_wdog->clk = clk;
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st_wdog->regmap = regmap;
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st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset");
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st_wdog->clkrate = clk_get_rate(st_wdog->clk);
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if (!st_wdog->clkrate) {
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dev_err(dev, "Unable to fetch clock rate\n");
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return -EINVAL;
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}
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st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;
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st_wdog_dev.parent = dev;
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ret = clk_prepare_enable(clk);
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if (ret) {
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dev_err(dev, "Unable to enable clock\n");
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return ret;
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}
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ret = devm_add_action_or_reset(dev, st_clk_disable_unprepare, clk);
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if (ret)
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return ret;
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watchdog_set_drvdata(&st_wdog_dev, st_wdog);
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watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);
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/* Init Watchdog timeout with value in DT */
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ret = watchdog_init_timeout(&st_wdog_dev, 0, dev);
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if (ret)
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return ret;
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ret = devm_watchdog_register_device(dev, &st_wdog_dev);
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if (ret)
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return ret;
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st_wdog_setup(st_wdog, true);
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dev_info(dev, "LPC Watchdog driver registered, reset type is %s",
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st_wdog->warm_reset ? "warm" : "cold");
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return ret;
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}
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static void st_wdog_remove(struct platform_device *pdev)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
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st_wdog_setup(st_wdog, false);
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}
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static int st_wdog_suspend(struct device *dev)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
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if (watchdog_active(&st_wdog_dev))
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st_wdog_stop(&st_wdog_dev);
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st_wdog_setup(st_wdog, false);
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clk_disable(st_wdog->clk);
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return 0;
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}
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static int st_wdog_resume(struct device *dev)
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{
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struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
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int ret;
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ret = clk_enable(st_wdog->clk);
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if (ret) {
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dev_err(dev, "Unable to re-enable clock\n");
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watchdog_unregister_device(&st_wdog_dev);
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clk_unprepare(st_wdog->clk);
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return ret;
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}
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st_wdog_setup(st_wdog, true);
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if (watchdog_active(&st_wdog_dev)) {
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st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
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st_wdog_start(&st_wdog_dev);
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}
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return 0;
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}
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static DEFINE_SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
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st_wdog_suspend, st_wdog_resume);
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static struct platform_driver st_wdog_driver = {
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.driver = {
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.name = "st-lpc-wdt",
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.pm = pm_sleep_ptr(&st_wdog_pm_ops),
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.of_match_table = st_wdog_match,
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},
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.probe = st_wdog_probe,
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.remove_new = st_wdog_remove,
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};
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module_platform_driver(st_wdog_driver);
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MODULE_AUTHOR("David Paris <david.paris@st.com>");
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MODULE_DESCRIPTION("ST LPC Watchdog Driver");
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MODULE_LICENSE("GPL");
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