On 22/07/2019 17:58:11+0200, Bruno Thomsen wrote: > Add partial support for the watchdog functionality of > PCF2127 and PCF2129 with Kconfig option. > > The programmable watchdog timer is currently using a fixed > clock source of 1Hz. This result in a selectable range of > 1-255 seconds, which covers most embedded Linux use-cases. > > Clock sources of 4096Hz, 64Hz and 1/60Hz is mostly useful > in MCU use-cases. > > Module parameter, wdt_margin, follows same interface as M41T80 > and DS1374 RTC drivers. > > Countdown timer not available when using watchdog feature. > > Signed-off-by: Bruno Thomsen <bruno.thomsen@xxxxxxxxx> > --- > drivers/rtc/Kconfig | 10 +++ > drivers/rtc/rtc-pcf2127.c | 155 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 165 insertions(+) > > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig > index e72f65b61176..45a123761784 100644 > --- a/drivers/rtc/Kconfig > +++ b/drivers/rtc/Kconfig > @@ -881,6 +881,16 @@ config RTC_DRV_PCF2127 > This driver can also be built as a module. If so, the module > will be called rtc-pcf2127. > > +config RTC_DRV_PCF2127_WDT > + bool "NXP PCF2127 watchdog timer" > + depends on RTC_DRV_PCF2127 > + help > + If you say Y here you will get support for the watchdog timer > + in the NXP PCF2127 and PCF2129 real-time clock chips. > + > + The watchdog is usually used together with systemd or the > + watchdog daemon. Watchdog trigger cause system reset. > + I wouldn't add a new Kconfig entry for that. How much bigger will it be? > config RTC_DRV_RV3029C2 > tristate "Micro Crystal RV3029/3049" > depends on RTC_I2C_AND_SPI > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > index ff09bedc02d4..442aa0a06886 100644 > --- a/drivers/rtc/rtc-pcf2127.c > +++ b/drivers/rtc/rtc-pcf2127.c > @@ -5,6 +5,9 @@ > * > * Author: Renaud Cerrato <r.cerrato@xxxxxxxxxxxxxxxxxxx> > * > + * Watchdog and tamper functions > + * Author: Bruno Thomsen <bruno.thomsen@xxxxxxxxx> > + * > * based on the other drivers in this same directory. > * > * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf > @@ -18,6 +21,10 @@ > #include <linux/module.h> > #include <linux/of.h> > #include <linux/regmap.h> > +#ifdef CONFIG_RTC_DRV_PCF2127_WDT > +#include <linux/miscdevice.h> > +#include <linux/watchdog.h> > +#endif > > /* Control register 1 */ > #define PCF2127_REG_CTRL1 0x00 > @@ -42,6 +49,13 @@ > #define PCF2127_REG_DW 0x07 > #define PCF2127_REG_MO 0x08 > #define PCF2127_REG_YR 0x09 > +/* Watchdog registers */ > +#define PCF2127_REG_WD_CTL 0x10 > +#define PCF2127_BIT_WD_CTL_TF0 BIT(0) > +#define PCF2127_BIT_WD_CTL_TF1 BIT(1) > +#define PCF2127_BIT_WD_CTL_CD0 BIT(6) > +#define PCF2127_BIT_WD_CTL_CD1 BIT(7) > +#define PCF2127_REG_WD_VAL 0x11 > /* Tamper timestamp registers */ > #define PCF2127_REG_TS_CTRL 0x12 > #define PCF2127_BIT_TS_CTRL_TSOFF BIT(6) > @@ -62,6 +76,11 @@ > #define PCF2127_REG_RAM_WRT_CMD 0x1C > #define PCF2127_REG_RAM_RD_CMD 0x1D > > +/* Watchdog timer value constants */ > +#define PCF2127_WD_VAL_STOP 0 > +#define PCF2127_WD_VAL_MIN 1 > +#define PCF2127_WD_VAL_MAX 255 > +#define PCF2127_WD_VAL_DEFAULT 60 > > struct pcf2127 { > struct rtc_device *rtc; > @@ -245,6 +264,108 @@ static int pcf2127_nvmem_write(void *priv, unsigned int offset, > return ret ?: bytes; > } > > +/* watchdog driver */ > + > +#ifdef CONFIG_RTC_DRV_PCF2127_WDT > + > +static struct pcf2127 *saved_pcf2127; > + > +static int wdt_margin = PCF2127_WD_VAL_DEFAULT; > +module_param(wdt_margin, int, 0); > +MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default " > + __stringify(PCF2127_WD_VAL_DEFAULT) "s)"); > + > +static void pcf2127_wdt_adjust_margin(int new_margin) > +{ > + if (new_margin < PCF2127_WD_VAL_MIN) > + new_margin = PCF2127_WD_VAL_DEFAULT; > + if (new_margin > PCF2127_WD_VAL_MAX) > + new_margin = PCF2127_WD_VAL_MAX; > + > + wdt_margin = new_margin; > +} > + > +static int pcf2127_wdt_ping(void) > +{ > + return regmap_write(saved_pcf2127->regmap, PCF2127_REG_WD_VAL, > + wdt_margin); > +} > + > +static int pcf2127_wdt_disable(void) > +{ > + return regmap_write(saved_pcf2127->regmap, PCF2127_REG_WD_VAL, > + PCF2127_WD_VAL_STOP); > +} > + > +static ssize_t pcf2127_wdt_write(struct file *file, const char __user *data, > + size_t len, loff_t *ppos) > +{ > + if (len) { > + pcf2127_wdt_ping(); > + return 1; > + } > + > + return 0; > +} > + > +static const struct watchdog_info pcf2127_wdt_info = { > + .identity = "NXP PCF2127/PCF2129 Watchdog", > + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, > +}; > + > +static long pcf2127_wdt_ioctl(struct file *file, unsigned int cmd, > + unsigned long arg) > +{ > + int options, new_margin; > + > + switch (cmd) { > + case WDIOC_GETSUPPORT: > + return copy_to_user((struct watchdog_info __user *)arg, > + &pcf2127_wdt_info, > + sizeof(pcf2127_wdt_info)) ? -EFAULT : 0; > + case WDIOC_SETOPTIONS: > + if (copy_from_user(&options, (int __user *)arg, sizeof(int))) > + return -EFAULT; > + if (options & WDIOS_DISABLECARD) { > + pr_info("%s: disable watchdog\n", __func__); > + return pcf2127_wdt_disable(); > + } > + if (options & WDIOS_ENABLECARD) { > + pr_info("%s: enable watchdog\n", __func__); > + return pcf2127_wdt_ping(); > + } > + return -EINVAL; > + case WDIOC_KEEPALIVE: > + return pcf2127_wdt_ping(); > + case WDIOC_SETTIMEOUT: > + if (get_user(new_margin, (int __user *)arg)) > + return -EFAULT; > + pcf2127_wdt_adjust_margin(new_margin); > + pr_info("%s: new watchdog timeout: %is (requested: %is)\n", > + __func__, wdt_margin, new_margin); > + pcf2127_wdt_ping(); > + /* Fall through */ > + case WDIOC_GETTIMEOUT: > + return put_user(wdt_margin, (int __user *)arg); > + default: > + return -ENOTTY; > + } > +} > + > +static const struct file_operations pcf2127_wdt_fops = { > + .owner = THIS_MODULE, > + .write = pcf2127_wdt_write, > + .unlocked_ioctl = pcf2127_wdt_ioctl, > +}; > + > +static struct miscdevice pcf2127_miscdev = { > + .minor = WATCHDOG_MINOR, > + .name = "watchdog", > + .fops = &pcf2127_wdt_fops, > +}; Wow, that is old school, please use the watchdog subsysteù. > + > +#endif /* CONFIG_RTC_DRV_PCF2127_WDT */ > + > /* sysfs interface */ > > static ssize_t timestamp0_store(struct device *dev, > @@ -394,6 +515,37 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > return ret; > } > > +#ifdef CONFIG_RTC_DRV_PCF2127_WDT > + /* > + * Watchdog timer enabled and reset pin /RST activated when timed out. > + * Select 1Hz clock source for watchdog timer. > + * Note: Countdown timer disabled and not available. > + */ > + ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_WD_CTL, > + PCF2127_BIT_WD_CTL_CD1 | > + PCF2127_BIT_WD_CTL_CD0 | > + PCF2127_BIT_WD_CTL_TF1 | > + PCF2127_BIT_WD_CTL_TF0, > + PCF2127_BIT_WD_CTL_CD1 | > + PCF2127_BIT_WD_CTL_CD0 | > + PCF2127_BIT_WD_CTL_TF1); > + if (ret) { > + dev_err(dev, "%s: watchdog config (wd_ctl) failed\n", __func__); > + return ret; > + } > + > + /* > + * Fails if another watchdog driver is loaded. > + */ > + ret = misc_register(&pcf2127_miscdev); > + if (ret) { > + dev_err(dev, "%s: watchdog register failed\n", __func__); > + return ret; > + } > + > + saved_pcf2127 = pcf2127; > +#endif /* CONFIG_RTC_DRV_PCF2127_WDT */ > + > ret = rtc_add_group(pcf2127->rtc, &pcf2127_attr_group); > if (ret) { > dev_err(dev, "%s: tamper register failed\n", __func__); > @@ -639,6 +791,9 @@ module_init(pcf2127_init) > > static void __exit pcf2127_exit(void) > { > +#ifdef CONFIG_RTC_DRV_PCF2127_WDT > + misc_deregister(&pcf2127_miscdev); > +#endif /* CONFIG_RTC_DRV_PCF2127_WDT */ > pcf2127_spi_unregister_driver(); > pcf2127_i2c_unregister_driver(); > } > -- > 2.21.0 > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
