watchdog: Add MAX6370 watchdog timer driver
MAX6370 watchdog is available e.g. on Freescale P1/P2 RDB-PC boards.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/watchdog/max6370_wdt.c b/drivers/watchdog/max6370_wdt.c
new file mode 100644
index 0000000..e59cbb2
--- /dev/null
+++ b/drivers/watchdog/max6370_wdt.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0+
+// (C) 2022 Pali Rohár <pali@kernel.org>
+
+#include <asm/io.h>
+#include <asm-generic/gpio.h>
+#include <dm.h>
+#include <linux/delay.h>
+#include <wdt.h>
+
+#define MAX6370_SET_MASK 0x7
+#define MAX6370_SET_1MS 0x0
+#define MAX6370_SET_10MS 0x1
+#define MAX6370_SET_30MS 0x2
+#define MAX6370_SET_DISABLE 0x3
+#define MAX6370_SET_100MS 0x4
+#define MAX6370_SET_1S 0x5
+#define MAX6370_SET_10S 0x6
+#define MAX6370_SET_60S 0x7
+
+#define MAX6370_WDI 0x8
+
+struct max6370_wdt {
+ void __iomem *reg;
+ struct gpio_desc gpio_wdi;
+};
+
+static int max6370_wdt_start(struct udevice *dev, u64 ms, ulong flags)
+{
+ struct max6370_wdt *wdt = dev_get_priv(dev);
+ u8 val;
+
+ val = readb(wdt->reg);
+ val &= ~MAX6370_SET_MASK;
+
+ if (ms <= 1)
+ val |= MAX6370_SET_1MS;
+ else if (ms <= 10)
+ val |= MAX6370_SET_10MS;
+ else if (ms <= 30)
+ val |= MAX6370_SET_30MS;
+ else if (ms <= 100)
+ val |= MAX6370_SET_100MS;
+ else if (ms <= 1000)
+ val |= MAX6370_SET_1S;
+ else if (ms <= 10000)
+ val |= MAX6370_SET_10S;
+ else
+ val |= MAX6370_SET_60S;
+
+ writeb(val, wdt->reg);
+
+ return 0;
+}
+
+static int max6370_wdt_stop(struct udevice *dev)
+{
+ struct max6370_wdt *wdt = dev_get_priv(dev);
+ u8 val;
+
+ val = readb(wdt->reg);
+ val &= ~MAX6370_SET_MASK;
+ val |= MAX6370_SET_DISABLE;
+ writeb(val, wdt->reg);
+
+ return 0;
+}
+
+static int max6370_wdt_reset(struct udevice *dev)
+{
+ struct max6370_wdt *wdt = dev_get_priv(dev);
+ u8 val;
+
+ if (dm_gpio_is_valid(&wdt->gpio_wdi)) {
+ dm_gpio_set_value(&wdt->gpio_wdi, 1);
+ udelay(1);
+ dm_gpio_set_value(&wdt->gpio_wdi, 0);
+ } else {
+ val = readb(wdt->reg);
+ writeb(val | MAX6370_WDI, wdt->reg);
+ writeb(val & ~MAX6370_WDI, wdt->reg);
+ }
+
+ return 0;
+}
+
+static int max6370_wdt_probe(struct udevice *dev)
+{
+ struct max6370_wdt *wdt = dev_get_priv(dev);
+
+ wdt->reg = dev_read_addr_ptr(dev);
+ if (!wdt->reg)
+ return -EINVAL;
+
+ /* WDI gpio is optional */
+ gpio_request_by_name(dev, "gpios", 0, &wdt->gpio_wdi, GPIOD_IS_OUT);
+
+ return 0;
+}
+
+static const struct wdt_ops max6370_wdt_ops = {
+ .start = max6370_wdt_start,
+ .stop = max6370_wdt_stop,
+ .reset = max6370_wdt_reset,
+};
+
+static const struct udevice_id max6370_wdt_ids[] = {
+ { .compatible = "maxim,max6370" },
+ {}
+};
+
+U_BOOT_DRIVER(max6370_wdt) = {
+ .name = "max6370_wdt",
+ .id = UCLASS_WDT,
+ .of_match = max6370_wdt_ids,
+ .probe = max6370_wdt_probe,
+ .priv_auto = sizeof(struct max6370_wdt),
+ .ops = &max6370_wdt_ops,
+};