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. Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@xxxxxxxxxxxxxxxxxxxx> --- Changes v2 -> v3: - rebase on master - remove the timeout table to simplify the logic (suggested by Guenter Roeck) - fix the set_timeout function (suggested by Guenter Roeck) - hardcode the max_hw_heartbeat_ms value based on the ts4600 max timeout value supported (suggested by Guenter Roeck) - remove the max_timeout usage and set a default timeout value (suggested by Guenter Roeck) - use the devm_watchdog_register_device function instead of watchdog_register_device (suggested by Guenter Roeck) 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) --- .../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 | 185 +++++++++++++++++++++ 5 files changed, 218 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 52a70ee6014f..408ad7c92cb3 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -520,6 +520,17 @@ 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 a2126e2a99ae..19553f27061a 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -62,6 +62,7 @@ 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..ed530dd2f800 --- /dev/null +++ b/drivers/watchdog/ts4600_wdt.c @@ -0,0 +1,185 @@ +/* + * 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) ")"); + +/* + * 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 + */ +#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; +}; + +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); + + 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; + } + + 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 = 2; + wdd->max_hw_heartbeat_ms = 10824; + wdd->timeout = 30; + + watchdog_set_drvdata(wdd, wdt); + watchdog_set_nowayout(wdd, nowayout); + watchdog_init_timeout(wdd, 0, dev); + + 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 = devm_watchdog_register_device(&pdev->dev, &wdt->wdd); + if (ret) { + dev_err(dev, "failed to register watchdog device\n"); + return ret; + } + + dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n", + wdd->timeout, nowayout); + + 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, + .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"); -- 2.12.0 -- 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