[PATCH v8 2/2] watchdog: Add watchdog driver for Sunplus SP7021

Xiantao Hu
2022-03-24T03:19:48Z

Sunplus SP7021 requires watchdog timer support.
Add watchdog driver to enable this.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
---
Changse in v8:
- no change.

MAINTAINERS | 1 +
drivers/watchdog/Kconfig | 11 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/sunplus_wdt.c | 220 +++++++++++++++++++++++++++++++++
4 files changed, 233 insertions(+)
create mode 100644 drivers/watchdog/sunplus_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index efdc618a0..0ba9e5495 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18549,6 +18549,7 @@ M: Xiantao Hu <xt.hu@cqplus1.com>
L: linux-watchdog@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
+F: drivers/watchdog/sunplus_wdt.c

SUPERH
M: Yoshinori Sato <ysato@users.sourceforge.jp>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index c8fa79da2..0639a2dab 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1011,6 +1011,17 @@ config APPLE_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called apple_wdt.

+config SUNPLUS_WATCHDOG
+ tristate "Sunplus watchdog support"
+ depends on ARCH_SUNPLUS || COMPILE_TEST
+ select WATCHDOG_CORE
+ help
+ Say Y here to include support for the watchdog timer
+ in Sunplus SoCs.
+
+ To compile this driver as a module, choose M here: the
+ module will be called sunplus_wdt.
+
# X86 (i386 + ia64 + x86_64) Architecture

config ACQUIRE_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index f7da867e8..71c933a59 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o
+obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o

# X86 (i386 + ia64 + x86_64) Architecture
obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
diff --git a/drivers/watchdog/sunplus_wdt.c b/drivers/watchdog/sunplus_wdt.c
new file mode 100644
index 000000000..e2d8c532b
--- /dev/null
+++ b/drivers/watchdog/sunplus_wdt.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sunplus Watchdog Driver
+ *
+ * Copyright (C) 2021 Sunplus Technology Co., Ltd.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/watchdog.h>
+
+#define WDT_CTRL 0x00
+#define WDT_CNT 0x04
+
+#define WDT_STOP 0x3877
+#define WDT_RESUME 0x4A4B
+#define WDT_CLRIRQ 0x7482
+#define WDT_UNLOCK 0xAB00
+#define WDT_LOCK 0xAB01
+#define WDT_CONMAX 0xDEAF
+
+/* TIMEOUT_MAX = ffff0/90kHz =11.65, so longer than 11 seconds will time out. */
+#define SP_WDT_MAX_TIMEOUT 11U
+#define SP_WDT_DEFAULT_TIMEOUT 10
+
+#define STC_CLK 90000
+
+#define DEVICE_NAME "sunplus-wdt"
+
+static unsigned int timeout;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+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) ")");
+
+struct sp_wdt_priv {
+ struct watchdog_device wdev;
+ void __iomem *base;
+ struct clk *clk;
+ struct reset_control *rstc;
+};
+
+static int sp_wdt_restart(struct watchdog_device *wdev,
+ unsigned long action, void *data)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+
+ writel(WDT_STOP, base + WDT_CTRL);
+ writel(WDT_UNLOCK, base + WDT_CTRL);
+ writel(0x0001, base + WDT_CNT);
+ writel(WDT_LOCK, base + WDT_CTRL);
+ writel(WDT_RESUME, base + WDT_CTRL);
+
+ return 0;
+}
+
+static int sp_wdt_ping(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+ u32 count;
+
+ if (wdev->timeout > SP_WDT_MAX_TIMEOUT) {
+ /* WDT_CONMAX sets the count to the maximum (down-counting). */
+ writel(WDT_CONMAX, base + WDT_CTRL);
+ } else {
+ writel(WDT_UNLOCK, base + WDT_CTRL);
+ /*
+ * Watchdog timer is a 20-bit down-counting based on STC_CLK.
+ * This register bits[16:0] is from bit[19:4] of the watchdog
+ * timer counter.
+ */
+ count = (wdev->timeout * STC_CLK) >> 4;
+ writel(count, base + WDT_CNT);
+ writel(WDT_LOCK, base + WDT_CTRL);
+ }
+
+ return 0;
+}
+
+static int sp_wdt_stop(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+
+ writel(WDT_STOP, base + WDT_CTRL);
+
+ return 0;
+}
+
+static int sp_wdt_start(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+
+ writel(WDT_RESUME, base + WDT_CTRL);
+
+ return 0;
+}
+
+static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+ u32 val;
+
+ val = readl(base + WDT_CNT);
+ val &= 0xffff;
+ val = val << 4;
+
+ return val;
+}
+
+static const struct watchdog_info sp_wdt_info = {
+ .identity = DEVICE_NAME,
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+};
+
+static const struct watchdog_ops sp_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = sp_wdt_start,
+ .stop = sp_wdt_stop,
+ .ping = sp_wdt_ping,
+ .get_timeleft = sp_wdt_get_timeleft,
+ .restart = sp_wdt_restart,
+};
+
+static void sp_clk_disable_unprepare(void *data)
+{
+ clk_disable_unprepare(data);
+}
+
+static void sp_reset_control_assert(void *data)
+{
+ reset_control_assert(data);
+}
+
+static int sp_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct sp_wdt_priv *priv;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk))
+ return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clock\n");
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to enable clock\n");
+
+ ret = devm_add_action_or_reset(dev, sp_clk_disable_unprepare, priv->clk);
+ if (ret)
+ return ret;
+
+ /* The timer and watchdog shared the STC reset */
+ priv->rstc = devm_reset_control_get_shared(dev, NULL);
+ if (IS_ERR(priv->rstc))
+ return dev_err_probe(dev, PTR_ERR(priv->rstc), "Failed to get reset\n");
+
+ reset_control_deassert(priv->rstc);
+
+ ret = devm_add_action_or_reset(dev, sp_reset_control_assert, priv->rstc);
+ if (ret)
+ return ret;
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->wdev.info = &sp_wdt_info;
+ priv->wdev.ops = &sp_wdt_ops;
+ priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
+ priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
+ priv->wdev.min_timeout = 1;
+ priv->wdev.parent = dev;
+
+ watchdog_set_drvdata(&priv->wdev, priv);
+ watchdog_init_timeout(&priv->wdev, timeout, dev);
+ watchdog_set_nowayout(&priv->wdev, nowayout);
+ watchdog_stop_on_reboot(&priv->wdev);
+ watchdog_set_restart_priority(&priv->wdev, 128);
+
+ return devm_watchdog_register_device(dev, &priv->wdev);
+}
+
+static const struct of_device_id sp_wdt_of_match[] = {
+ {.compatible = "sunplus,sp7021-wdt", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
+
+static struct platform_driver sp_wdt_driver = {
+ .probe = sp_wdt_probe,
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = sp_wdt_of_match,
+ },
+};
+
+module_platform_driver(sp_wdt_driver);
+
+MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>");
+MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
+MODULE_LICENSE("GPL");
--
2.33.1