gpio: driver for AMD Promontory

This patch adds a new GPIO driver for AMD Promontory chip.

This GPIO controller is enumerated by ACPI and the ACPI compliant
hardware ID is AMDF030.

Change history:

v2: 1. fix coding style
    2. registers renaming
v3: 1. change include file
    2. fix coding style
    3. remove module_init/exit, add module_platform_driver
    4. remove MODULE_ALIAS
v4: 1. change TOTAL_GPIO_PINS to PT_TOTAL_GPIO
    2. remove PCI dependency in Kconfig
    3. fix subject line

Signed-off-by: YD Tseng <Yd_Tseng@asmedia.com.tw>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 261 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-amdpt.c b/drivers/gpio/gpio-amdpt.c
new file mode 100644
index 0000000..cbbb966
--- /dev/null
+++ b/drivers/gpio/gpio-amdpt.c
@@ -0,0 +1,261 @@
+/*
+ * AMD Promontory GPIO driver
+ *
+ * Copyright (C) 2015 ASMedia Technology Inc.
+ * Author: YD Tseng <yd_tseng@asmedia.com.tw>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio/driver.h>
+#include <linux/spinlock.h>
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+
+#define PT_TOTAL_GPIO 8
+
+/* PCI-E MMIO register offsets */
+#define PT_DIRECTION_REG   0x00
+#define PT_INPUTDATA_REG   0x04
+#define PT_OUTPUTDATA_REG  0x08
+#define PT_CLOCKRATE_REG   0x0C
+#define PT_SYNC_REG        0x28
+
+struct pt_gpio_chip {
+	struct gpio_chip         gc;
+	void __iomem             *reg_base;
+	spinlock_t               lock;
+};
+
+#define to_pt_gpio(c)	container_of(c, struct pt_gpio_chip, gc)
+
+static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
+{
+	struct pt_gpio_chip *pt_gpio = to_pt_gpio(gc);
+	unsigned long flags;
+	u32 using_pins;
+
+	dev_dbg(gc->dev, "pt_gpio_request offset=%x\n", offset);
+
+	spin_lock_irqsave(&pt_gpio->lock, flags);
+
+	using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
+	if (using_pins & BIT(offset)) {
+		dev_warn(gc->dev, "PT GPIO pin %x reconfigured\n",
+			offset);
+		spin_unlock_irqrestore(&pt_gpio->lock, flags);
+		return -EINVAL;
+	}
+
+	writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
+
+	spin_unlock_irqrestore(&pt_gpio->lock, flags);
+
+	return 0;
+}
+
+static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
+{
+	struct pt_gpio_chip *pt_gpio = to_pt_gpio(gc);
+	unsigned long flags;
+	u32 using_pins;
+
+	spin_lock_irqsave(&pt_gpio->lock, flags);
+
+	using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
+	using_pins &= ~BIT(offset);
+	writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
+
+	spin_unlock_irqrestore(&pt_gpio->lock, flags);
+
+	dev_dbg(gc->dev, "pt_gpio_free offset=%x\n", offset);
+}
+
+static void pt_gpio_set_value(struct gpio_chip *gc, unsigned offset, int value)
+{
+	struct pt_gpio_chip *pt_gpio = to_pt_gpio(gc);
+	unsigned long flags;
+	u32 data;
+
+	dev_dbg(gc->dev, "pt_gpio_set_value offset=%x, value=%x\n",
+		offset, value);
+
+	spin_lock_irqsave(&pt_gpio->lock, flags);
+
+	data = readl(pt_gpio->reg_base + PT_OUTPUTDATA_REG);
+	data &= ~BIT(offset);
+	if (value)
+		data |= BIT(offset);
+	writel(data, pt_gpio->reg_base + PT_OUTPUTDATA_REG);
+
+	spin_unlock_irqrestore(&pt_gpio->lock, flags);
+}
+
+static int pt_gpio_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	struct pt_gpio_chip *pt_gpio = to_pt_gpio(gc);
+	unsigned long flags;
+	u32 data;
+
+	spin_lock_irqsave(&pt_gpio->lock, flags);
+
+	data = readl(pt_gpio->reg_base + PT_DIRECTION_REG);
+
+	/* configure as output */
+	if (data & BIT(offset))
+		data = readl(pt_gpio->reg_base + PT_OUTPUTDATA_REG);
+	else	/* configure as input */
+		data = readl(pt_gpio->reg_base + PT_INPUTDATA_REG);
+
+	spin_unlock_irqrestore(&pt_gpio->lock, flags);
+
+	data >>= offset;
+	data &= 1;
+
+	dev_dbg(gc->dev, "pt_gpio_get_value offset=%x, value=%x\n",
+		offset, data);
+
+	return data;
+}
+
+static int pt_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	struct pt_gpio_chip *pt_gpio = to_pt_gpio(gc);
+	unsigned long flags;
+	u32 data;
+
+	dev_dbg(gc->dev, "pt_gpio_dirction_input offset=%x\n", offset);
+
+	spin_lock_irqsave(&pt_gpio->lock, flags);
+
+	data = readl(pt_gpio->reg_base + PT_DIRECTION_REG);
+	data &= ~BIT(offset);
+	writel(data, pt_gpio->reg_base + PT_DIRECTION_REG);
+
+	spin_unlock_irqrestore(&pt_gpio->lock, flags);
+
+	return 0;
+}
+
+static int pt_gpio_direction_output(struct gpio_chip *gc,
+					unsigned offset, int value)
+{
+	struct pt_gpio_chip *pt_gpio = to_pt_gpio(gc);
+	unsigned long flags;
+	u32 data;
+
+	dev_dbg(gc->dev, "pt_gpio_direction_output offset=%x, value=%x\n",
+		offset, value);
+
+	spin_lock_irqsave(&pt_gpio->lock, flags);
+
+	data = readl(pt_gpio->reg_base + PT_OUTPUTDATA_REG);
+	if (value)
+		data |= BIT(offset);
+	else
+		data &= ~BIT(offset);
+	writel(data, pt_gpio->reg_base + PT_OUTPUTDATA_REG);
+
+	data = readl(pt_gpio->reg_base + PT_DIRECTION_REG);
+	data |= BIT(offset);
+	writel(data, pt_gpio->reg_base + PT_DIRECTION_REG);
+
+	spin_unlock_irqrestore(&pt_gpio->lock, flags);
+
+	return 0;
+}
+
+static int pt_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct acpi_device *acpi_dev;
+	acpi_handle handle = ACPI_HANDLE(dev);
+	struct pt_gpio_chip *pt_gpio;
+	struct resource *res_mem;
+	int ret = 0;
+
+	if (acpi_bus_get_device(handle, &acpi_dev)) {
+		dev_err(dev, "PT GPIO device node not found\n");
+		return -ENODEV;
+	}
+
+	pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
+	if (!pt_gpio)
+		return -ENOMEM;
+
+	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res_mem) {
+		dev_err(&pdev->dev, "Failed to get MMIO resource for PT GPIO.\n");
+		return -EINVAL;
+	}
+	pt_gpio->reg_base = devm_ioremap_resource(dev, res_mem);
+	if (IS_ERR(pt_gpio->reg_base)) {
+		dev_err(&pdev->dev, "Failed to map MMIO resource for PT GPIO.\n");
+		return PTR_ERR(pt_gpio->reg_base);
+	}
+
+	spin_lock_init(&pt_gpio->lock);
+
+	pt_gpio->gc.label            = pdev->name;
+	pt_gpio->gc.owner            = THIS_MODULE;
+	pt_gpio->gc.dev              = dev;
+	pt_gpio->gc.request          = pt_gpio_request;
+	pt_gpio->gc.free             = pt_gpio_free;
+	pt_gpio->gc.direction_input  = pt_gpio_direction_input;
+	pt_gpio->gc.direction_output = pt_gpio_direction_output;
+	pt_gpio->gc.get              = pt_gpio_get_value;
+	pt_gpio->gc.set              = pt_gpio_set_value;
+	pt_gpio->gc.base             = -1;
+	pt_gpio->gc.ngpio            = PT_TOTAL_GPIO;
+#if defined(CONFIG_OF_GPIO)
+	pt_gpio->gc.of_node          = pdev->dev.of_node;
+#endif
+	ret = gpiochip_add(&pt_gpio->gc);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register GPIO lib\n");
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pt_gpio);
+
+	/* initialize register setting */
+	writel(0, pt_gpio->reg_base + PT_SYNC_REG);
+	writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
+
+	dev_dbg(&pdev->dev, "PT GPIO driver loaded\n");
+	return ret;
+}
+
+static int pt_gpio_remove(struct platform_device *pdev)
+{
+	struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
+
+	gpiochip_remove(&pt_gpio->gc);
+
+	return 0;
+}
+
+static const struct acpi_device_id pt_gpio_acpi_match[] = {
+	{ "AMDF030", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
+
+static struct platform_driver pt_gpio_driver = {
+	.driver = {
+		.name = "pt-gpio",
+		.acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
+	},
+	.probe = pt_gpio_probe,
+	.remove = pt_gpio_remove,
+};
+
+module_platform_driver(pt_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
+MODULE_DESCRIPTION("AMD Promontory GPIO Driver");