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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Watchdog driver for the A21 VME CPU Boards4 *5 * Copyright (C) 2013 MEN Mikro Elektronik Nuernberg GmbH6 *7 */8#include <linux/module.h>9#include <linux/moduleparam.h>10#include <linux/types.h>11#include <linux/kernel.h>12#include <linux/slab.h>13#include <linux/platform_device.h>14#include <linux/watchdog.h>15#include <linux/uaccess.h>16#include <linux/gpio/consumer.h>17#include <linux/delay.h>18#include <linux/bitops.h>19#include <linux/of.h>20 21#define NUM_GPIOS 622 23enum a21_wdt_gpios {24 GPIO_WD_ENAB,25 GPIO_WD_FAST,26 GPIO_WD_TRIG,27 GPIO_WD_RST0,28 GPIO_WD_RST1,29 GPIO_WD_RST2,30};31 32struct a21_wdt_drv {33 struct watchdog_device wdt;34 struct gpio_desc *gpios[NUM_GPIOS];35};36 37static bool nowayout = WATCHDOG_NOWAYOUT;38module_param(nowayout, bool, 0);39MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");41 42static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)43{44 int reset = 0;45 46 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;47 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;48 reset |= gpiod_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;49 50 return reset;51}52 53static int a21_wdt_start(struct watchdog_device *wdt)54{55 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);56 57 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 1);58 59 return 0;60}61 62static int a21_wdt_stop(struct watchdog_device *wdt)63{64 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);65 66 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);67 68 return 0;69}70 71static int a21_wdt_ping(struct watchdog_device *wdt)72{73 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);74 75 gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 0);76 ndelay(10);77 gpiod_set_value(drv->gpios[GPIO_WD_TRIG], 1);78 79 return 0;80}81 82static int a21_wdt_set_timeout(struct watchdog_device *wdt,83 unsigned int timeout)84{85 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);86 87 if (timeout != 1 && timeout != 30) {88 dev_err(wdt->parent, "Only 1 and 30 allowed as timeout\n");89 return -EINVAL;90 }91 92 if (timeout == 30 && wdt->timeout == 1) {93 dev_err(wdt->parent,94 "Transition from fast to slow mode not allowed\n");95 return -EINVAL;96 }97 98 if (timeout == 1)99 gpiod_set_value(drv->gpios[GPIO_WD_FAST], 1);100 else101 gpiod_set_value(drv->gpios[GPIO_WD_FAST], 0);102 103 wdt->timeout = timeout;104 105 return 0;106}107 108static const struct watchdog_info a21_wdt_info = {109 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,110 .identity = "MEN A21 Watchdog",111};112 113static const struct watchdog_ops a21_wdt_ops = {114 .owner = THIS_MODULE,115 .start = a21_wdt_start,116 .stop = a21_wdt_stop,117 .ping = a21_wdt_ping,118 .set_timeout = a21_wdt_set_timeout,119};120 121static struct watchdog_device a21_wdt = {122 .info = &a21_wdt_info,123 .ops = &a21_wdt_ops,124 .min_timeout = 1,125 .max_timeout = 30,126};127 128static int a21_wdt_probe(struct platform_device *pdev)129{130 struct device *dev = &pdev->dev;131 struct a21_wdt_drv *drv;132 unsigned int reset = 0;133 int num_gpios;134 int ret;135 int i;136 137 drv = devm_kzalloc(dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);138 if (!drv)139 return -ENOMEM;140 141 num_gpios = gpiod_count(dev, NULL);142 if (num_gpios != NUM_GPIOS) {143 dev_err(dev, "gpios DT property wrong, got %d want %d",144 num_gpios, NUM_GPIOS);145 return -ENODEV;146 }147 148 /* Request the used GPIOs */149 for (i = 0; i < num_gpios; i++) {150 enum gpiod_flags gflags;151 152 if (i < GPIO_WD_RST0)153 gflags = GPIOD_ASIS;154 else155 gflags = GPIOD_IN;156 drv->gpios[i] = devm_gpiod_get_index(dev, NULL, i, gflags);157 if (IS_ERR(drv->gpios[i]))158 return PTR_ERR(drv->gpios[i]);159 160 gpiod_set_consumer_name(drv->gpios[i], "MEN A21 Watchdog");161 162 /*163 * Retrieve the initial value from the GPIOs that should be164 * output, then set up the line as output with that value.165 */166 if (i < GPIO_WD_RST0) {167 int val;168 169 val = gpiod_get_value(drv->gpios[i]);170 gpiod_direction_output(drv->gpios[i], val);171 }172 }173 174 watchdog_init_timeout(&a21_wdt, 30, dev);175 watchdog_set_nowayout(&a21_wdt, nowayout);176 watchdog_set_drvdata(&a21_wdt, drv);177 a21_wdt.parent = dev;178 179 reset = a21_wdt_get_bootstatus(drv);180 if (reset == 2)181 a21_wdt.bootstatus |= WDIOF_EXTERN1;182 else if (reset == 4)183 a21_wdt.bootstatus |= WDIOF_CARDRESET;184 else if (reset == 5)185 a21_wdt.bootstatus |= WDIOF_POWERUNDER;186 else if (reset == 7)187 a21_wdt.bootstatus |= WDIOF_EXTERN2;188 189 drv->wdt = a21_wdt;190 dev_set_drvdata(dev, drv);191 192 ret = devm_watchdog_register_device(dev, &a21_wdt);193 if (ret)194 return ret;195 196 dev_info(dev, "MEN A21 watchdog timer driver enabled\n");197 198 return 0;199}200 201static void a21_wdt_shutdown(struct platform_device *pdev)202{203 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);204 205 gpiod_set_value(drv->gpios[GPIO_WD_ENAB], 0);206}207 208static const struct of_device_id a21_wdt_ids[] = {209 { .compatible = "men,a021-wdt" },210 { },211};212MODULE_DEVICE_TABLE(of, a21_wdt_ids);213 214static struct platform_driver a21_wdt_driver = {215 .probe = a21_wdt_probe,216 .shutdown = a21_wdt_shutdown,217 .driver = {218 .name = "a21-watchdog",219 .of_match_table = a21_wdt_ids,220 },221};222 223module_platform_driver(a21_wdt_driver);224 225MODULE_AUTHOR("MEN Mikro Elektronik");226MODULE_DESCRIPTION("MEN A21 Watchdog");227MODULE_LICENSE("GPL");228MODULE_ALIAS("platform:a21-watchdog");229