power: reset: Add AT91 poweroff driver

Add a driver to handle the shutdown of the Atmel SoCs. This code used to be
(and still is) in arch/arm/mach-at91. We didn't remove it yet so that we can
convert all the boards to using this driver, before removing it entirely in a
separate patch.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

3 files changed, 165 insertions, 0 deletions

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 360bac75a3da..1f9d0c53fc14 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -14,6 +14,14 @@ config POWER_RESET_AS3722
         help
           This driver supports turning off board via a ams AS3722 power-off.
 
+config POWER_RESET_AT91_POWEROFF
+        bool "Atmel AT91 poweroff driver"
+        depends on MACH_AT91
+        default SOC_AT91SAM9 || SOC_SAMA5
+        help
+          This driver supports poweroff for Atmel AT91SAM9 and SAMA5
+          SoCs
+
 config POWER_RESET_AT91_RESET
         bool "Atmel AT91 reset driver"
         depends on MACH_AT91
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 1599214b91d9..8bf941bac3da 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_POWER_RESET_AS3722) += as3722-poweroff.o
+obj-$(CONFIG_POWER_RESET_AT91_POWEROFF) += at91-poweroff.o
 obj-$(CONFIG_POWER_RESET_AT91_RESET) += at91-reset.o
 obj-$(CONFIG_POWER_RESET_AXXIA) += axxia-reset.o
 obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
diff --git a/drivers/power/reset/at91-poweroff.c b/drivers/power/reset/at91-poweroff.c
new file mode 100644
index 000000000000..40bf42d146f1
--- /dev/null
+++ b/drivers/power/reset/at91-poweroff.c
@@ -0,0 +1,156 @@
+/*
+ * Atmel AT91 SAM9 SoCs reset code
+ *
+ * Copyright (C) 2007 Atmel Corporation.
+ * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ * Copyright (C) 2014 Free Electrons
+ *
+ * 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/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+
+#define AT91_SHDW_CR    0x00            /* Shut Down Control Register */
+#define AT91_SHDW_SHDW          BIT(0)                  /* Shut Down command */
+#define AT91_SHDW_KEY           (0xa5 << 24)            /* KEY Password */
+
+#define AT91_SHDW_MR    0x04            /* Shut Down Mode Register */
+#define AT91_SHDW_WKMODE0       GENMASK(2, 0)           /* Wake-up 0 Mode Selection */
+#define AT91_SHDW_CPTWK0_MAX    0xf                     /* Maximum Counter On Wake Up 0 */
+#define AT91_SHDW_CPTWK0        (AT91_SHDW_CPTWK0_MAX << 4) /* Counter On Wake Up 0 */
+#define AT91_SHDW_CPTWK0_(x)    ((x) << 4)
+#define AT91_SHDW_RTTWKEN       BIT(16)                 /* Real Time Timer Wake-up Enable */
+#define AT91_SHDW_RTCWKEN       BIT(17)                 /* Real Time Clock Wake-up Enable */
+
+#define AT91_SHDW_SR    0x08            /* Shut Down Status Register */
+#define AT91_SHDW_WAKEUP0       BIT(0)                  /* Wake-up 0 Status */
+#define AT91_SHDW_RTTWK         BIT(16)                 /* Real-time Timer Wake-up */
+#define AT91_SHDW_RTCWK         BIT(17)                 /* Real-time Clock Wake-up [SAM9RL] */
+
+enum wakeup_type {
+        AT91_SHDW_WKMODE0_NONE          = 0,
+        AT91_SHDW_WKMODE0_HIGH          = 1,
+        AT91_SHDW_WKMODE0_LOW           = 2,
+        AT91_SHDW_WKMODE0_ANYLEVEL      = 3,
+};
+
+static const char *shdwc_wakeup_modes[] = {
+        [AT91_SHDW_WKMODE0_NONE]        = "none",
+        [AT91_SHDW_WKMODE0_HIGH]        = "high",
+        [AT91_SHDW_WKMODE0_LOW]         = "low",
+        [AT91_SHDW_WKMODE0_ANYLEVEL]    = "any",
+};
+
+static void __iomem *at91_shdwc_base;
+
+static void __init at91_wakeup_status(void)
+{
+        u32 reg = readl(at91_shdwc_base);
+        char *reason = "unknown";
+
+        /* Simple power-on, just bail out */
+        if (!reg)
+                return;
+
+        if (reg & AT91_SHDW_RTTWK)
+                reason = "RTT";
+        else if (reg & AT91_SHDW_RTCWK)
+                reason = "RTC";
+
+        pr_info("AT91: Wake-Up source: %s\n", reason);
+}
+
+static void at91_poweroff(void)
+{
+        writel(AT91_SHDW_KEY | AT91_SHDW_SHDW, at91_shdwc_base + AT91_SHDW_CR);
+}
+
+const enum wakeup_type at91_poweroff_get_wakeup_mode(struct device_node *np)
+{
+        const char *pm;
+        int err, i;
+
+        err = of_property_read_string(np, "atmel,wakeup-mode", &pm);
+        if (err < 0)
+                return AT91_SHDW_WKMODE0_ANYLEVEL;
+
+        for (i = 0; i < ARRAY_SIZE(shdwc_wakeup_modes); i++)
+                if (!strcasecmp(pm, shdwc_wakeup_modes[i]))
+                        return i;
+
+        return -ENODEV;
+}
+
+static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
+{
+        struct device_node *np = pdev->dev.of_node;
+        enum wakeup_type wakeup_mode;
+        u32 mode = 0, tmp;
+
+        wakeup_mode = at91_poweroff_get_wakeup_mode(np);
+        if (wakeup_mode < 0) {
+                dev_warn(&pdev->dev, "shdwc unknown wakeup mode\n");
+                return;
+        }
+
+        if (!of_property_read_u32(np, "atmel,wakeup-counter", &tmp)) {
+                if (tmp > AT91_SHDW_CPTWK0_MAX) {
+                        dev_warn(&pdev->dev,
+                                 "shdwc wakeup counter 0x%x > 0x%x reduce it to 0x%x\n",
+                                 tmp, AT91_SHDW_CPTWK0_MAX, AT91_SHDW_CPTWK0_MAX);
+                        tmp = AT91_SHDW_CPTWK0_MAX;
+                }
+                mode |= AT91_SHDW_CPTWK0_(tmp);
+        }
+
+        if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
+                        mode |= AT91_SHDW_RTCWKEN;
+
+        if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
+                        mode |= AT91_SHDW_RTTWKEN;
+
+        writel(wakeup_mode | mode, at91_shdwc_base + AT91_SHDW_MR);
+}
+
+static int at91_poweroff_probe(struct platform_device *pdev)
+{
+        struct resource *res;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(at91_shdwc_base)) {
+                dev_err(&pdev->dev, "Could not map reset controller address\n");
+                return PTR_ERR(at91_shdwc_base);
+        }
+
+        at91_wakeup_status();
+
+        if (pdev->dev.of_node)
+                at91_poweroff_dt_set_wakeup_mode(pdev);
+
+        pm_power_off = at91_poweroff;
+
+        return 0;
+}
+
+static struct of_device_id at91_poweroff_of_match[] = {
+        { .compatible = "atmel,at91sam9260-shdwc", },
+        { .compatible = "atmel,at91sam9rl-shdwc", },
+        { .compatible = "atmel,at91sam9x5-shdwc", },
+        { /*sentinel*/ }
+};
+
+static struct platform_driver at91_poweroff_driver = {
+        .probe = at91_poweroff_probe,
+        .driver = {
+                .name = "at91-poweroff",
+                .of_match_table = at91_poweroff_of_match,
+        },
+};
+module_platform_driver(at91_poweroff_driver);