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/Kconfig b/drivers/watchdog/Kconfig
index 03e8e72..c3eb8a8 100644 (file)
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -168,6 +168,13 @@ config WDT_GPIO
          doc/device-tree-bindings/watchdog/gpio-wdt.txt for
          information on how to describe the watchdog in device tree.
 
+config WDT_MAX6370
+       bool "MAX6370 watchdog timer support"
+       depends on WDT
+       select DM_GPIO
+       help
+         Select this to enable max6370 watchdog timer.
+
 config WDT_MPC8xx
        bool "MPC8xx watchdog timer support"
        depends on WDT && MPC8xx

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index c0b4c9f..1f6199b 100644 (file)
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o
 obj-$(CONFIG_WDT_ORION) += orion_wdt.o
 obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
 obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
+obj-$(CONFIG_WDT_MAX6370) += max6370_wdt.o
 obj-$(CONFIG_WDT_MPC8xx) += mpc8xx_wdt.o
 obj-$(CONFIG_WDT_MT7620) += mt7620_wdt.o
 obj-$(CONFIG_WDT_MT7621) += mt7621_wdt.o

diff --git a/drivers/watchdog/max6370_wdt.c b/drivers/watchdog/max6370_wdt.c
new file mode 100644 (file)
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,
+};