[PATCH] PPC: Add support for CTS-1000 GPIO controlled system poweroff
Ben Collins
ben.c at servergy.com
Tue Dec 18 01:19:28 EST 2012
CTS-1000 is based on P4080. GPIO 27 is used to signal the FPGA to
switch off power, and also associates IRQ 8 with front-panel button
press (which we use to call orderly_poweroff()).
The relevant device-tree looks like this:
gpio0: gpio at 130000 {
compatible = "fsl,qoriq-gpio";
reg = <0x130000 0x1000>;
interrupts = <55 2 0 0>;
#gpio-cells = <2>;
gpio-controller;
/* Allows powering off the system via GPIO signal. */
gpio-halt at 27 {
compatible = "sgy,gpio-halt";
gpios = <&gpio0 27 0>;
interrupts = <8 1 0 0>;
};
};
Because the driver cannot match on sgy,gpio-halt (because the node is never
processed through of_platform), it matches on fsl,qoriq-gpio and then
checks child nodes for the matching sgy,gpio-halt. This also ensures that
the GPIO controller is detected prior to sgy_cts1000's probe callback,
since that node wont match via of_platform until the controller is
registered.
Also, because the GPIO handler for triggering system poweroff might sleep,
the IRQ uses a workqueue to call orderly_poweroff().
As a final note, this driver may be expanded for other features specific to
the CTS-1000.
Signed-off-by: Ben Collins <ben.c at servergy.com>
Cc: Jack Smith <jack.s at servergy.com>
Cc: Vihar Rai <vihar.r at servergy.com>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
arch/powerpc/platforms/85xx/Kconfig | 8 ++
arch/powerpc/platforms/85xx/Makefile | 1 +
arch/powerpc/platforms/85xx/sgy_cts1000.c | 176 +++++++++++++++++++++++++++++
3 files changed, 185 insertions(+)
create mode 100644 arch/powerpc/platforms/85xx/sgy_cts1000.c
diff --git a/arch/powerpc/platforms/85xx/Kconfig b/arch/powerpc/platforms/85xx/Kconfig
index 02d02a0..651788c 100644
--- a/arch/powerpc/platforms/85xx/Kconfig
+++ b/arch/powerpc/platforms/85xx/Kconfig
@@ -245,6 +245,14 @@ config P4080_DS
help
This option enables support for the P4080 DS board
+config SGY_CTS1000
+ tristate "Servergy CTS-1000 support"
+ select GPIOLIB
+ select OF_GPIO
+ depends on P4080_DS
+ help
+ Enable this to support functionality in Servergy's CTS-1000 systems.
+
endif # PPC32
config P5020_DS
diff --git a/arch/powerpc/platforms/85xx/Makefile b/arch/powerpc/platforms/85xx/Makefile
index 76f679c..9db31dc 100644
--- a/arch/powerpc/platforms/85xx/Makefile
+++ b/arch/powerpc/platforms/85xx/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_KSI8560) += ksi8560.o
obj-$(CONFIG_XES_MPC85xx) += xes_mpc85xx.o
obj-$(CONFIG_GE_IMP3A) += ge_imp3a.o
obj-$(CONFIG_PPC_QEMU_E500) += qemu_e500.o
+obj-$(CONFIG_SGY_CTS1000) += sgy_cts1000.o
diff --git a/arch/powerpc/platforms/85xx/sgy_cts1000.c b/arch/powerpc/platforms/85xx/sgy_cts1000.c
new file mode 100644
index 0000000..611e92f
--- /dev/null
+++ b/arch/powerpc/platforms/85xx/sgy_cts1000.c
@@ -0,0 +1,176 @@
+/*
+ * Servergy CTS-1000 Setup
+ *
+ * Maintained by Ben Collins <ben.c at servergy.com>
+ *
+ * Copyright 2012 by Servergy, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/of_gpio.h>
+#include <linux/workqueue.h>
+#include <linux/reboot.h>
+#include <linux/interrupt.h>
+
+#include <asm/machdep.h>
+
+static struct device_node *halt_node;
+
+static struct of_device_id child_match[] = {
+ {
+ .compatible = "sgy,gpio-halt",
+ },
+ {},
+};
+
+static void gpio_halt_wfn(struct work_struct *work)
+{
+ /* Likely wont return */
+ orderly_poweroff(true);
+}
+static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);
+
+static void gpio_halt_cb(void)
+{
+ enum of_gpio_flags flags;
+ int trigger, gpio;
+
+ if (!halt_node)
+ return;
+
+ gpio = of_get_gpio_flags(halt_node, 0, &flags);
+
+ if (!gpio_is_valid(gpio))
+ return;
+
+ trigger = (flags == OF_GPIO_ACTIVE_LOW);
+
+ printk(KERN_INFO "gpio-halt: triggering GPIO.\n");
+
+ /* Probably wont return */
+ gpio_set_value(gpio, trigger);
+}
+
+/* This IRQ means someone pressed the power button and it is waiting for us
+ * to handle the shutdown/poweroff. */
+static irqreturn_t gpio_halt_irq(int irq, void *__data)
+{
+ printk(KERN_INFO "gpio-halt: shutdown due to power button IRQ.\n");
+ schedule_work(&gpio_halt_wq);
+
+ return IRQ_HANDLED;
+};
+
+static int __devinit gpio_halt_probe(struct platform_device *pdev)
+{
+ enum of_gpio_flags flags;
+ struct device_node *node = pdev->dev.of_node;
+ int gpio, err, irq;
+ int trigger;
+
+ if (!node)
+ return -ENODEV;
+
+ /* If there's no matching child, this isn't really an error */
+ halt_node = of_find_matching_node(node, child_match);
+ if (!halt_node)
+ return 0;
+
+ /* Technically we could just read the first one, but punish
+ * DT writers for invalid form. */
+ if (of_gpio_count(halt_node) != 1)
+ return -EINVAL;
+
+ /* Get the gpio number relative to the dynamic base. */
+ gpio = of_get_gpio_flags(halt_node, 0, &flags);
+ if (!gpio_is_valid(gpio))
+ return -EINVAL;
+
+ err = gpio_request(gpio, "gpio-halt");
+ if (err) {
+ printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
+ gpio);
+ halt_node = NULL;
+ return err;
+ }
+
+ trigger = (flags == OF_GPIO_ACTIVE_LOW);
+
+ gpio_direction_output(gpio, !trigger);
+
+ /* Now get the IRQ which tells us when the power button is hit */
+ irq = irq_of_parse_and_map(halt_node, 0);
+ err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);
+ if (err) {
+ printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
+ "GPIO %d.\n", irq, gpio);
+ gpio_free(gpio);
+ halt_node = NULL;
+ return err;
+ }
+
+ /* Register our halt function */
+ ppc_md.halt = gpio_halt_cb;
+ ppc_md.power_off = gpio_halt_cb;
+
+ printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
+ " irq).\n", gpio, trigger, irq);
+
+ return 0;
+}
+
+static int __devexit gpio_halt_remove(struct platform_device *pdev)
+{
+ if (halt_node) {
+ int gpio = of_get_gpio(halt_node, 0);
+ int irq = irq_of_parse_and_map(halt_node, 0);
+
+ free_irq(irq, halt_node);
+
+ ppc_md.halt = NULL;
+ ppc_md.power_off = NULL;
+
+ gpio_free(gpio);
+
+ halt_node = NULL;
+ }
+
+ return 0;
+}
+
+static struct of_device_id gpio_halt_match[] = {
+ /* We match on the gpio bus itself and scan the children since they
+ * wont be matched against us. We know the bus wont match until it
+ * has been registered too. */
+ {
+ .compatible = "fsl,qoriq-gpio",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gpio_halt_match);
+
+static struct platform_driver gpio_halt_driver = {
+ .driver = {
+ .name = "gpio-halt",
+ .owner = THIS_MODULE,
+ .of_match_table = gpio_halt_match,
+ },
+ .probe = gpio_halt_probe,
+ .remove = __devexit_p(gpio_halt_remove),
+};
+
+module_platform_driver(gpio_halt_driver);
+
+MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
+MODULE_VERSION("1.0");
+MODULE_AUTHOR("Ben Collins <ben.c at servergy.com>");
+MODULE_LICENSE("GPL");
--
1.7.10.4
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