[PATCH 6/6] watchdog: ts4600: add driver for TS-4600 watchdog
From: linux@roeck-us.net (Guenter Roeck)
Date: 2016-12-23 01:53:56
Also in:
linux-devicetree, linux-watchdog, lkml
On 12/14/2016 03:12 PM, Sebastien Bourdelin wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- .../devicetree/bindings/watchdog/ts4600-wdt.txt | 16 ++ arch/arm/boot/dts/imx28-ts4600-common.dtsi | 5 + drivers/watchdog/Kconfig | 10 + drivers/watchdog/Makefile | 1 + drivers/watchdog/ts4600_wdt.c | 213 +++++++++++++++++++++ 5 files changed, 245 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt create mode 100644 drivers/watchdog/ts4600_wdt.cdiff --git a/Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt b/Documentation/devicetree/bindings/watchdog/ts4600-wdt.txt new file mode 100644 index 0000000..61d620e --- /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: + +wdt { + 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 b668933..dd7318c 100644 --- a/arch/arm/boot/dts/imx28-ts4600-common.dtsi +++ b/arch/arm/boot/dts/imx28-ts4600-common.dtsi@@ -116,6 +116,11 @@ strobe-gpios = <&gpio0 25 GPIO_ACTIVE_HIGH>; ale-gpios = <&gpio0 26 GPIO_ACTIVE_HIGH>; rdy-gpios = <&gpio0 21 GPIO_ACTIVE_HIGH>; + + wdt at 2a { + compatible = "technologic,ts4600-wdt"; + reg = <0x2a>; + }; }; };diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 3eb58cb..7a8e176 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig@@ -500,6 +500,16 @@ 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 HAS_IOMEM && OF + depends on SOC_IMX28 || COMPILE_TEST
Asd 0day reports, this does not work.
quoted hunk ↗ jump to hunk
+ 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 && OFdiff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index caa9f4a..d4b4bd2 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.odiff --git a/drivers/watchdog/ts4600_wdt.c b/drivers/watchdog/ts4600_wdt.c new file mode 100644 index 0000000..db91b40 --- /dev/null +++ b/drivers/watchdog/ts4600_wdt.c@@ -0,0 +1,213 @@ +/* + * Watchdog driver for TS-4600 based boards + * + * Copyright (c) 2016 - Savoir-faire Linux + * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com> + * + * 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@savoirfairelinux.com>. + */ + +#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; + 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 }, +}; + +#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->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; + + for (i = 0; i < MAX_TIMEOUT_INDEX; i++) { + if (ts4600_wdt_map[i].timeout >= timeout) + break; + }
An if/else would be much simpler here.
+
+ wdd->timeout = ts4600_wdt_map[i].timeout;
+ wdt->feed_val = ts4600_wdt_map[i].regval;
+
+ 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_node *np = pdev->dev.of_node;
+ 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;
+ }
+
+ /* check for the NBUS state and defer the probing if it is not ready */
+ if (!ts_nbus_is_ready())
+ return -EPROBE_DEFER;
+
+ /* allocate memory for watchdog struct */
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ /* set offset to know where to write */
+ wdt->feed_offset = reg;
+
+ /* Initialize struct watchdog_device */
+ wdd = &wdt->wdd;
+ wdd->parent = &pdev->dev;
+ wdd->info = &ts4600_wdt_info;
+ wdd->ops = &ts4600_wdt_ops;
+ wdd->min_timeout = ts4600_wdt_map[0].timeout;
+ wdd->max_timeout = ts4600_wdt_map[MAX_TIMEOUT_INDEX].timeout;
+Your call, but it might be better and more flexible to just use a single hardware timeout (such as the 2.x second one), provide it here as max_hw_heartbeat_ms, and let the kernel handle the actual (and larger) timeouts.
+ watchdog_set_drvdata(wdd, wdt);
+ watchdog_set_nowayout(wdd, nowayout);
+ watchdog_init_timeout(wdd, 0, &pdev->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;
+ 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);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to register watchdog device\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+
+ dev_info(&pdev->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 [off-list ref]");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:ts4600_wdt");