On Fri, Feb 03, 2017 at 02:47:29PM -0500, Sebastien Bourdelin wrote: > This watchdog is instantiated in a FPGA and can only be access using a > GPIOs bit-banged bus, called the NBUS by Technologic Systems. > The watchdog is made of only one register, called the feed register. > Writing to this register will re-arm the watchdog for a given time (and > enable it if it was disable). It can be disabled by writing a special > value into it. > --- > Changes v1 -> v2: > - rebase on master > - retrieve the ts_nbus instantiated by the parent node (suggested by > Linus Walleij) > - rename the wdt by watchdog in the device tree and in the > documentation (suggested by Rob Herring) > - add a dependency to the TS_NBUS driver in the Kconfig (suggested by > Guenter Roeck) > - simplify the set_timeout function (suggested by Guenter Roeck) > - use the max_hw_heartbeat_ms callback instead of the max_timeout > callback (suggested by Guenter Roeck) > > Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@xxxxxxxxxxxxxxxxxxxx> > --- > .../devicetree/bindings/watchdog/ts4600-wdt.txt | 16 ++ > arch/arm/boot/dts/imx28-ts4600-common.dtsi | 5 + > drivers/watchdog/Kconfig | 11 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/ts4600_wdt.c | 217 +++++++++++++++++++++ > 5 files changed, 250 insertions(+) > create mode 100644 Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt > create mode 100644 drivers/watchdog/ts4600_wdt.c > > diff --git a/Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt b/Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt > new file mode 100644 > index 000000000000..7de00ceae341 > --- /dev/null > +++ b/Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt > @@ -0,0 +1,16 @@ > +TS-4600 Technologic Systems Watchdog > + > +Required properties: > +- compatible: must be "technologic,ts4600-wdt" > +- reg: offset to the FPGA's watchdog register > + > +Optional property: > +- timeout-sec: contains the watchdog timeout in seconds. > + > +Example: > + > +watchdog { > + compatible = "technologic,ts4600-wdt"; > + reg = <0x2a>; > + timeout-sec = <10>; > +}; > diff --git a/arch/arm/boot/dts/imx28-ts4600-common.dtsi b/arch/arm/boot/dts/imx28-ts4600-common.dtsi > index c6282d5479de..092c2eed0fe7 100644 > --- a/arch/arm/boot/dts/imx28-ts4600-common.dtsi > +++ b/arch/arm/boot/dts/imx28-ts4600-common.dtsi > @@ -116,6 +116,11 @@ > ts-strobe-gpios = <&gpio0 25 GPIO_ACTIVE_HIGH>; > ts-ale-gpios = <&gpio0 26 GPIO_ACTIVE_HIGH>; > ts-rdy-gpios = <&gpio0 21 GPIO_ACTIVE_HIGH>; > + > + watchdog@2a { > + compatible = "technologic,ts4600-wdt"; > + reg = <0x2a>; > + }; > }; > > }; > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index acb00b53a520..ab1355eefad1 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -500,6 +500,17 @@ config NUC900_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called nuc900_wdt. > > +config TS4600_WATCHDOG > + tristate "TS-4600 Watchdog" > + depends on TS_NBUS > + depends on HAS_IOMEM && OF > + depends on SOC_IMX28 || COMPILE_TEST > + select WATCHDOG_CORE > + help > + Technologic Systems TS-4600 has watchdog timer implemented in > + an external FPGA. Say Y here if you want to support for the > + watchdog timer on TS-4600 board. > + > config TS4800_WATCHDOG > tristate "TS-4800 Watchdog" > depends on HAS_IOMEM && OF > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 0c3d35e3c334..d5e164d2b4cd 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -61,6 +61,7 @@ obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o > obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o > obj-$(CONFIG_STMP3XXX_RTC_WATCHDOG) += stmp3xxx_rtc_wdt.o > obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o > +obj-$(CONFIG_TS4600_WATCHDOG) += ts4600_wdt.o > obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o > obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o > obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o > diff --git a/drivers/watchdog/ts4600_wdt.c b/drivers/watchdog/ts4600_wdt.c > new file mode 100644 > index 000000000000..d7bf6cc04986 > --- /dev/null > +++ b/drivers/watchdog/ts4600_wdt.c > @@ -0,0 +1,217 @@ > +/* > + * Watchdog driver for TS-4600 based boards > + * > + * Copyright (c) 2016 - Savoir-faire Linux > + * Author: Sebastien Bourdelin <sebastien.bourdelin@xxxxxxxxxxxxxxxxxxxx> > + * > + * This file is licensed under the terms of the GNU General Public > + * License version 2. This program is licensed "as is" without any > + * warranty of any kind, whether express or implied. > + * > + * The watchdog on the TS-4600 based boards is in an FPGA and can only be > + * accessed using a GPIO bit-banged bus called the NBUS by Technologic Systems. > + * The logic for the watchdog is the same then for the TS-4800 SoM, only the way > + * to access it change, therefore this driver is heavely based on the ts4800_wdt > + * driver from Damien Riegel <damien.riegel@xxxxxxxxxxxxxxxxxxxx>. > + */ > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/ts-nbus.h> > +#include <linux/watchdog.h> > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +module_param(nowayout, bool, 0); > +MODULE_PARM_DESC(nowayout, > + "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +/* possible feed values */ > +#define TS4600_WDT_FEED_2S 0x1 > +#define TS4600_WDT_FEED_10S 0x2 > +#define TS4600_WDT_DISABLE 0x3 > + > +struct ts4600_wdt { > + struct watchdog_device wdd; > + struct ts_nbus *ts_nbus; > + u32 feed_offset; > + u32 feed_val; > +}; > + > +/* > + * TS-4600 supports the following timeout values: > + * > + * value desc > + * --------------------- > + * 0 feed for 338ms > + * 1 feed for 2.706s > + * 2 feed for 10.824s > + * 3 disable watchdog > + * > + * Keep the regmap/timeout map ordered by timeout > + */ > +static const struct { > + const int timeout; > + const int regval; > +} ts4600_wdt_map[] = { > + { 2, TS4600_WDT_FEED_2S }, > + { 10, TS4600_WDT_FEED_10S }, > +}; Does this table really do any good ? Seems to me it might be simpler to just use raw values where needed. > + > +#define MAX_TIMEOUT_INDEX (ARRAY_SIZE(ts4600_wdt_map) - 1) > + > +static void ts4600_write_feed(struct ts4600_wdt *wdt, u32 val) > +{ > + ts_nbus_write(wdt->ts_nbus, wdt->feed_offset, val); > +} > + > +static int ts4600_wdt_start(struct watchdog_device *wdd) > +{ > + struct ts4600_wdt *wdt = watchdog_get_drvdata(wdd); > + > + ts4600_write_feed(wdt, wdt->feed_val); > + > + return 0; > +} > + > +static int ts4600_wdt_stop(struct watchdog_device *wdd) > +{ > + struct ts4600_wdt *wdt = watchdog_get_drvdata(wdd); > + > + ts4600_write_feed(wdt, TS4600_WDT_DISABLE); > + return 0; > +} > + > +static int ts4600_wdt_set_timeout(struct watchdog_device *wdd, > + unsigned int timeout) > +{ > + struct ts4600_wdt *wdt = watchdog_get_drvdata(wdd); > + int i = 0; > + > + if (ts4600_wdt_map[i].timeout < timeout) > + i = MAX_TIMEOUT_INDEX; > + > + wdd->timeout = ts4600_wdt_map[i].timeout; This is not correct. you would only set wdd->timeout to the value from the table if the timeout is <= the requested timeout. Otherwise, set the requested timeout value. Otherwise the timeout will be set to a maximum of 10 seconds, and using the core to support larger timeouts does not work. > + wdt->feed_val = ts4600_wdt_map[i].regval; > + FWIW, personally I think that if (timeout <= 2) { wdd->timeout = 2; wdt->feed_val = TS4600_WDT_FEED_2S; } else { wdd->timeout = timeout < 10 ? 10 : timeout; wdt->feed_val = TS4600_WDT_FEED_10S; } would be simpler than dealing with the table. > + return 0; > +} > + > +static const struct watchdog_ops ts4600_wdt_ops = { > + .owner = THIS_MODULE, > + .start = ts4600_wdt_start, > + .stop = ts4600_wdt_stop, > + .set_timeout = ts4600_wdt_set_timeout, > +}; > + > +static const struct watchdog_info ts4600_wdt_info = { > + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, > + .identity = "TS-4600 Watchdog", > +}; > + > +static int ts4600_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *np = dev->of_node; > + struct ts_nbus *ts_nbus; > + struct watchdog_device *wdd; > + struct ts4600_wdt *wdt; > + u32 reg; > + int ret; > + > + ret = of_property_read_u32(np, "reg", ®); > + if (ret < 0) { > + dev_err(&pdev->dev, "missing reg property\n"); > + return ret; > + } > + > + /* allocate memory for watchdog struct */ > + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > + return -ENOMEM; > + > + /* set offset to know where to write */ > + wdt->feed_offset = reg; > + > + /* keep a pointer to the ts_nbus instanciated by the parent node */ > + ts_nbus = dev_get_drvdata(dev->parent); > + if (!ts_nbus) { > + dev_err(dev, "missing ts-nbus compatible parent node\n"); > + return PTR_ERR(ts_nbus); > + } > + wdt->ts_nbus = ts_nbus; > + > + /* Initialize struct watchdog_device */ > + wdd = &wdt->wdd; > + wdd->parent = dev; > + wdd->info = &ts4600_wdt_info; > + wdd->ops = &ts4600_wdt_ops; > + wdd->min_timeout = ts4600_wdt_map[0].timeout; > + wdd->max_hw_heartbeat_ms = > + ts4600_wdt_map[MAX_TIMEOUT_INDEX].timeout * 1000; Why not 10824 ? > + > + watchdog_set_drvdata(wdd, wdt); > + watchdog_set_nowayout(wdd, nowayout); > + watchdog_init_timeout(wdd, 0, dev); > + > + /* > + * As this watchdog supports only a few values, ts4600_wdt_set_timeout > + * must be called to initialize timeout and feed_val with valid values. > + * Default to maximum timeout if none, or an invalid one, is provided in > + * device tree. > + */ > + if (!wdd->timeout) > + wdd->timeout = wdd->max_timeout; There is no max_timeout anymore. Just initialize timeout with a value of your choice, such as 30 seconds, before calling watchdog_init_timeout(). > + ts4600_wdt_set_timeout(wdd, wdd->timeout); > + > + /* > + * The feed register is write-only, so it is not possible to determine > + * watchdog's state. Disable it to be in a known state. > + */ > + ts4600_wdt_stop(wdd); > + > + ret = watchdog_register_device(wdd); Optimal candidate for devm_wtchdog_register_device(). It lets you drop the remove function and platform_set_drvdata(). > + if (ret) { > + dev_err(dev, "failed to register watchdog device\n"); > + return ret; > + } > + > + platform_set_drvdata(pdev, wdt); > + > + dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n", > + wdd->timeout, nowayout); > + > + return 0; > +} > + > +static int ts4600_wdt_remove(struct platform_device *pdev) > +{ > + struct ts4600_wdt *wdt = platform_get_drvdata(pdev); > + > + watchdog_unregister_device(&wdt->wdd); > + > + return 0; > +} > + > +static const struct of_device_id ts4600_wdt_of_match[] = { > + { .compatible = "technologic,ts4600-wdt", }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, ts4600_wdt_of_match); > + > +static struct platform_driver ts4600_wdt_driver = { > + .probe = ts4600_wdt_probe, > + .remove = ts4600_wdt_remove, > + .driver = { > + .name = "ts4600_wdt", > + .of_match_table = ts4600_wdt_of_match, > + }, > +}; > + > +module_platform_driver(ts4600_wdt_driver); > + > +MODULE_AUTHOR("Sebastien Bourdelin <sebastien.bourdelin@xxxxxxxxxxxxxxxxxxxx>"); > +MODULE_LICENSE("GPL v2"); > +MODULE_ALIAS("platform:ts4600_wdt"); -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html