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path: root/drivers/power/reset/gemini-poweroff.c
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Diffstat (limited to 'drivers/power/reset/gemini-poweroff.c')
-rw-r--r--drivers/power/reset/gemini-poweroff.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/power/reset/gemini-poweroff.c b/drivers/power/reset/gemini-poweroff.c
new file mode 100644
index 000000000..b7f7a8225
--- /dev/null
+++ b/drivers/power/reset/gemini-poweroff.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Gemini power management controller
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Inspired by code from the SL3516 board support by Jason Lee
+ * Inspired by code from Janos Laube <janos.dev@gmail.com>
+ */
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/reboot.h>
+
+#define GEMINI_PWC_ID 0x00010500
+#define GEMINI_PWC_IDREG 0x00
+#define GEMINI_PWC_CTRLREG 0x04
+#define GEMINI_PWC_STATREG 0x08
+
+#define GEMINI_CTRL_SHUTDOWN BIT(0)
+#define GEMINI_CTRL_ENABLE BIT(1)
+#define GEMINI_CTRL_IRQ_CLR BIT(2)
+
+#define GEMINI_STAT_CIR BIT(4)
+#define GEMINI_STAT_RTC BIT(5)
+#define GEMINI_STAT_POWERBUTTON BIT(6)
+
+struct gemini_powercon {
+ struct device *dev;
+ void __iomem *base;
+};
+
+static irqreturn_t gemini_powerbutton_interrupt(int irq, void *data)
+{
+ struct gemini_powercon *gpw = data;
+ u32 val;
+
+ /* ACK the IRQ */
+ val = readl(gpw->base + GEMINI_PWC_CTRLREG);
+ val |= GEMINI_CTRL_IRQ_CLR;
+ writel(val, gpw->base + GEMINI_PWC_CTRLREG);
+
+ val = readl(gpw->base + GEMINI_PWC_STATREG);
+ val &= 0x70U;
+ switch (val) {
+ case GEMINI_STAT_CIR:
+ /*
+ * We do not yet have a driver for the infrared
+ * controller so it can cause spurious poweroff
+ * events. Ignore those for now.
+ */
+ dev_info(gpw->dev, "infrared poweroff - ignored\n");
+ break;
+ case GEMINI_STAT_RTC:
+ dev_info(gpw->dev, "RTC poweroff\n");
+ orderly_poweroff(true);
+ break;
+ case GEMINI_STAT_POWERBUTTON:
+ dev_info(gpw->dev, "poweroff button pressed\n");
+ orderly_poweroff(true);
+ break;
+ default:
+ dev_info(gpw->dev, "other power management IRQ\n");
+ break;
+ }
+
+ return IRQ_HANDLED;
+}
+
+/* This callback needs this static local as it has void as argument */
+static struct gemini_powercon *gpw_poweroff;
+
+static void gemini_poweroff(void)
+{
+ struct gemini_powercon *gpw = gpw_poweroff;
+ u32 val;
+
+ dev_crit(gpw->dev, "Gemini power off\n");
+ val = readl(gpw->base + GEMINI_PWC_CTRLREG);
+ val |= GEMINI_CTRL_ENABLE | GEMINI_CTRL_IRQ_CLR;
+ writel(val, gpw->base + GEMINI_PWC_CTRLREG);
+
+ val &= ~GEMINI_CTRL_ENABLE;
+ val |= GEMINI_CTRL_SHUTDOWN;
+ writel(val, gpw->base + GEMINI_PWC_CTRLREG);
+}
+
+static int gemini_poweroff_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct gemini_powercon *gpw;
+ u32 val;
+ int irq;
+ int ret;
+
+ gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
+ if (!gpw)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ gpw->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(gpw->base))
+ return PTR_ERR(gpw->base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ gpw->dev = dev;
+
+ val = readl(gpw->base + GEMINI_PWC_IDREG);
+ val &= 0xFFFFFF00U;
+ if (val != GEMINI_PWC_ID) {
+ dev_err(dev, "wrong power controller ID: %08x\n",
+ val);
+ return -ENODEV;
+ }
+
+ /*
+ * Enable the power controller. This is crucial on Gemini
+ * systems: if this is not done, pressing the power button
+ * will result in unconditional poweroff without any warning.
+ * This makes the kernel handle the poweroff.
+ */
+ val = readl(gpw->base + GEMINI_PWC_CTRLREG);
+ val |= GEMINI_CTRL_ENABLE;
+ writel(val, gpw->base + GEMINI_PWC_CTRLREG);
+
+ /* Clear the IRQ */
+ val = readl(gpw->base + GEMINI_PWC_CTRLREG);
+ val |= GEMINI_CTRL_IRQ_CLR;
+ writel(val, gpw->base + GEMINI_PWC_CTRLREG);
+
+ /* Wait for this to clear */
+ val = readl(gpw->base + GEMINI_PWC_STATREG);
+ while (val & 0x70U)
+ val = readl(gpw->base + GEMINI_PWC_STATREG);
+
+ /* Clear the IRQ again */
+ val = readl(gpw->base + GEMINI_PWC_CTRLREG);
+ val |= GEMINI_CTRL_IRQ_CLR;
+ writel(val, gpw->base + GEMINI_PWC_CTRLREG);
+
+ ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
+ "poweroff", gpw);
+ if (ret)
+ return ret;
+
+ pm_power_off = gemini_poweroff;
+ gpw_poweroff = gpw;
+
+ dev_info(dev, "Gemini poweroff driver registered\n");
+
+ return 0;
+}
+
+static const struct of_device_id gemini_poweroff_of_match[] = {
+ {
+ .compatible = "cortina,gemini-power-controller",
+ },
+ {}
+};
+
+static struct platform_driver gemini_poweroff_driver = {
+ .probe = gemini_poweroff_probe,
+ .driver = {
+ .name = "gemini-poweroff",
+ .of_match_table = gemini_poweroff_of_match,
+ },
+};
+builtin_platform_driver(gemini_poweroff_driver);