[PATCH v2 3/5] watchdog: ts4800: add driver for TS-4800 watchdog

Damien Riegel
2015-10-29T20:52:30Z

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
---
.../devicetree/bindings/mfd/ts4800-syscon.txt | 8 +
.../devicetree/bindings/watchdog/ts4800-wdt.txt | 12 ++
drivers/mfd/Kconfig | 1 +
drivers/mfd/ts4800-syscon.c | 13 +-
drivers/watchdog/Kconfig | 10 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/ts4800_wdt.c | 216 +++++++++++++++++++++
7 files changed, 260 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt
create mode 100644 drivers/watchdog/ts4800_wdt.c

diff --git a/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt b/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
index 8dbc12c..8c0fd1d 100644
--- a/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
+++ b/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
@@ -4,9 +4,17 @@ Required properties:
- compatible : must be "ts,ts4800-syscon"
- reg : physical base address and length of memory mapped region

+The driver exposes following subdevices:
+- a watchdog: see ../watchdog/ts4800-wdt.txt
+
Example:

syscon@b0010000 {
compatible = "ts,ts4800-syscon";
reg = <0xb0010000 0x3d>;
+
+ wdt@e {
+ compatible = "ts,ts4800-wdt";
+ offset = <0xe>;
+ };
};
diff --git a/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt b/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt
new file mode 100644
index 0000000..a9305c2
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt
@@ -0,0 +1,12 @@
+Technologic Systems Watchdog
+
+Required properties:
+- compatible : must be "ts,ts4800-wdt"
+- offset : offset of the feed register from syscon base
+
+Example:
+
+wdt1: wdt@b0010000 {
+ compatible = "ts,ts4800-wdt";
+ offset = <0xe>;
+};
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 8f03dce..95ba036 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1304,6 +1304,7 @@ config MFD_TC6393XB

config MFD_TS4800_SYSCON
tristate "TS-4800 Syscon Support"
+ select MFD_CORE
select REGMAP
select REGMAP_MMIO
help
diff --git a/drivers/mfd/ts4800-syscon.c b/drivers/mfd/ts4800-syscon.c
index 1e42e96..03b3b04a 100644
--- a/drivers/mfd/ts4800-syscon.c
+++ b/drivers/mfd/ts4800-syscon.c
@@ -24,6 +24,13 @@
#include <linux/mfd/ts4800-syscon.h>

+static const struct mfd_cell ts4800_syscon_cells[] = {
+ {
+ .name = "ts4800-watchdog",
+ .of_compatible = "ts,ts4800-wdt",
+ },
+};
+
static const struct regmap_config ts4800_regmap_config = {
.reg_bits = 32,
.reg_stride = 2,
@@ -56,11 +63,15 @@ static int ts4800_syscon_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, syscon);

- return 0;
+ return mfd_add_devices(&pdev->dev, -1, ts4800_syscon_cells,
+ ARRAY_SIZE(ts4800_syscon_cells),
+ NULL, 0, NULL);
}

static int ts4800_syscon_remove(struct platform_device *pdev)
{
+ mfd_remove_devices(&pdev->dev);
+
return 0;
}

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 241fafd..aaa42b8 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -417,6 +417,16 @@ config NUC900_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called nuc900_wdt.

+config TS4800_WATCHDOG
+ tristate "TS-4800 Watchdog"
+ depends on OF
+ depends on MFD_TS4800_SYSCON
+ select WATCHDOG_CORE
+ help
+ Technologic Systems TS-4800 has watchdog timer implemented in
+ an external FPGA. Say Y here if you want to support for the
+ watchdog timer on TS-4800 board.
+
config TS72XX_WATCHDOG
tristate "TS-72XX SBC Watchdog"
depends on MACH_TS72XX
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 59ea9a1..435fc93 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -52,6 +52,7 @@ 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-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o
obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
diff --git a/drivers/watchdog/ts4800_wdt.c b/drivers/watchdog/ts4800_wdt.c
new file mode 100644
index 0000000..9b9e638
--- /dev/null
+++ b/drivers/watchdog/ts4800_wdt.c
@@ -0,0 +1,216 @@
+/*
+ * ts4800_wdt.c - Watchdog driver for TS-4800 based boards
+ *
+ * Copyright (c) 2015 - Savoir-faire Linux
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/mfd/ts4800-syscon.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 TS4800_WDT_FEED_2S 0x1
+#define TS4800_WDT_FEED_10S 0x2
+#define TS4800_WDT_DISABLE 0x3
+
+
+struct ts4800_wdt {
+ struct watchdog_device wdd;
+ struct regmap *regmap;
+ u32 feed_offset;
+ u16 feed_val;
+};
+
+/*
+ * TS-4800 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;
+} ts4800_wdt_map[] = {
+ { 2, TS4800_WDT_FEED_2S },
+ { 10, TS4800_WDT_FEED_10S },
+};
+
+static int timeout_to_regval(struct watchdog_device *wdd, int new_timeout)
+{
+ int i;
+
+ new_timeout = clamp_val(new_timeout,
+ wdd->min_timeout, wdd->max_timeout);
+
+ for (i = 0; i < ARRAY_SIZE(ts4800_wdt_map); i++) {
+ if (ts4800_wdt_map[i].timeout >= new_timeout)
+ return ts4800_wdt_map[i].timeout;
+ }
+
+ return -EINVAL;
+}
+
+static void ts4800_write_feed(struct ts4800_wdt *wdt, u16 val)
+{
+ regmap_write(wdt->regmap, wdt->feed_offset, val);
+}
+
+static int ts4800_wdt_ping(struct watchdog_device *wdd)
+{
+ struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ ts4800_write_feed(wdt, wdt->feed_val);
+ return 0;
+}
+
+static int ts4800_wdt_stop(struct watchdog_device *wdd)
+{
+ struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ ts4800_write_feed(wdt, TS4800_WDT_DISABLE);
+ return 0;
+}
+
+static int ts4800_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int new_timeout)
+{
+ struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
+ int val = timeout_to_regval(wdd, new_timeout);
+
+ if (val < 0)
+ return val;
+
+ wdt->feed_val = (u16) val;
+
+ return 0;
+}
+
+static const struct watchdog_ops ts4800_wdt_ops = {
+ .owner = THIS_MODULE,
+ /*
+ * pinging the watchdog enables it, so use same function
+ * for pinging and starting the watchdog
+ */
+ .start = ts4800_wdt_ping,
+ .stop = ts4800_wdt_stop,
+ .ping = ts4800_wdt_ping,
+ .set_timeout = ts4800_wdt_set_timeout,
+};
+
+static const struct watchdog_info ts4800_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+ .identity = "TS-4800 Watchdog",
+};
+
+static int ts4800_wdt_probe(struct platform_device *pdev)
+{
+ int max_timeout_index = ARRAY_SIZE(ts4800_wdt_map) - 1;
+ struct device_node *np = pdev->dev.of_node;
+ struct ts4800_syscon *syscon;
+ struct watchdog_device *wdd;
+ struct ts4800_wdt *wdt;
+ u32 offset;
+ int ret;
+
+ ret = of_property_read_u32(np, "offset", &offset);
+ if (ret) {
+ dev_err(&pdev->dev, "An offset must be provided\n");
+ return -EINVAL;
+ }
+
+ /* allocate memory for watchdog struct */
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ /* set regmap and offset to know where to write */
+ syscon = dev_get_drvdata(pdev->dev.parent);
+ wdt->regmap = syscon->regmap;
+ wdt->feed_offset = offset;
+
+ /* Initialize struct watchdog_device */
+ wdd = &wdt->wdd;
+ wdd->info = &ts4800_wdt_info;
+ wdd->ops = &ts4800_wdt_ops;
+ wdd->min_timeout = ts4800_wdt_map[0].timeout;
+ wdd->max_timeout = ts4800_wdt_map[max_timeout_index].timeout;
+ wdd->timeout = wdd->max_timeout;
+ wdt->feed_val = ts4800_wdt_map[max_timeout_index].regval;
+
+ watchdog_set_drvdata(wdd, wdt);
+ watchdog_set_nowayout(wdd, nowayout);
+
+ /*
+ * Must be called after watchdog_set_drvdata to dereference a valid
+ * pointer. The feed register is write-only, so it is not possible to
+ * determine if watchdog is already started or not. Disable it to be in
+ * a known state.
+ */
+ ts4800_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 ts4800_wdt_remove(struct platform_device *pdev)
+{
+ struct ts4800_wdt *wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&wdt->wdd);
+
+ return 0;
+}
+
+static const struct of_device_id ts4800_wdt_of_match[] = {
+ { .compatible = "ts,ts4800-wdt", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ts4800_wdt_of_match);
+
+static struct platform_driver ts4800_wdt_driver = {
+ .probe = ts4800_wdt_probe,
+ .remove = ts4800_wdt_remove,
+ .driver = {
+ .name = "ts4800_wdt",
+ .of_match_table = ts4800_wdt_of_match,
+ },
+};
+
+module_platform_driver(ts4800_wdt_driver);
+
+MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ts4800_wdt");
--
2.5.0