gpio: AMD G-Series PCH gpio driver

GPIO platform driver for the AMD G-series PCH (eg. on GX-412TC)

This driver doesn't registers itself automatically, as it needs to
be provided with platform specific configuration, provided by some
board driver setup code.

Didn't implement oftree probing yet, as it's rarely found on x86.

Cc: linux-gpio@vger.kernel.org
Cc: linus.walleij@linaro.org
Cc: bgolaszewski@baylibre.com
Cc: dvhart@infradead.org
Cc: platform-driver-x86@vger.kernel.org
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 185 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-amd-fch.c b/drivers/gpio/gpio-amd-fch.c
new file mode 100644
index 000000000000..3b4fdce325c1
--- /dev/null
+++ b/drivers/gpio/gpio-amd-fch.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * GPIO driver for the AMD G series FCH (eg. GX-412TC)
+ *
+ * Copyright (C) 2018 metux IT consult
+ * Author: Enrico Weigelt, metux IT consult <info@metux.net>
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_data/gpio/gpio-amd-fch.h>
+#include <linux/spinlock.h>
+
+#define AMD_FCH_MMIO_BASE		0xFED80000
+#define AMD_FCH_GPIO_BANK0_BASE		0x1500
+#define AMD_FCH_GPIO_SIZE		0x0300
+
+#define AMD_FCH_GPIO_FLAG_DIRECTION	BIT(23)
+#define AMD_FCH_GPIO_FLAG_WRITE		BIT(22)
+#define AMD_FCH_GPIO_FLAG_READ		BIT(16)
+
+static const struct resource amd_fch_gpio_iores =
+	DEFINE_RES_MEM_NAMED(
+		AMD_FCH_MMIO_BASE + AMD_FCH_GPIO_BANK0_BASE,
+		AMD_FCH_GPIO_SIZE,
+		"amd-fch-gpio-iomem");
+
+struct amd_fch_gpio_priv {
+	struct platform_device		*pdev;
+	struct gpio_chip		gc;
+	void __iomem			*base;
+	struct amd_fch_gpio_pdata	*pdata;
+	spinlock_t			lock;
+};
+
+static void *amd_fch_gpio_addr(struct amd_fch_gpio_priv *priv,
+			       unsigned int gpio)
+{
+	return priv->base + priv->pdata->gpio_reg[gpio]*sizeof(u32);
+}
+
+static int amd_fch_gpio_direction_input(struct gpio_chip *gc,
+					unsigned int offset)
+{
+	unsigned long flags;
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+	void *ptr = amd_fch_gpio_addr(priv, offset);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	writel_relaxed(readl_relaxed(ptr) & ~AMD_FCH_GPIO_FLAG_DIRECTION, ptr);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int amd_fch_gpio_direction_output(struct gpio_chip *gc,
+					 unsigned int gpio, int value)
+{
+	unsigned long flags;
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+	void *ptr = amd_fch_gpio_addr(priv, gpio);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	writel_relaxed(readl_relaxed(ptr) | AMD_FCH_GPIO_FLAG_DIRECTION, ptr);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int amd_fch_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
+{
+	int ret;
+	unsigned long flags;
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+	void *ptr = amd_fch_gpio_addr(priv, gpio);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = (readl_relaxed(ptr) & AMD_FCH_GPIO_FLAG_DIRECTION);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static void amd_fch_gpio_set(struct gpio_chip *gc,
+			     unsigned int gpio, int value)
+{
+	unsigned long flags;
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+	void *ptr = amd_fch_gpio_addr(priv, gpio);
+	u32 mask;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	mask = readl_relaxed(ptr);
+	if (value)
+		mask |= AMD_FCH_GPIO_FLAG_WRITE;
+	else
+		mask &= ~AMD_FCH_GPIO_FLAG_WRITE;
+	writel_relaxed(mask, ptr);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static int amd_fch_gpio_get(struct gpio_chip *gc,
+			    unsigned int offset)
+{
+	unsigned long flags;
+	int ret;
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+	void *ptr = amd_fch_gpio_addr(priv, offset);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = (readl_relaxed(ptr) & AMD_FCH_GPIO_FLAG_READ);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static int amd_fch_gpio_request(struct gpio_chip *chip,
+				unsigned int gpio_pin)
+{
+	return 0;
+}
+
+static int amd_fch_gpio_probe(struct platform_device *pdev)
+{
+	struct amd_fch_gpio_priv *priv;
+	struct amd_fch_gpio_pdata *pdata;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform_data\n");
+		return -ENOENT;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->pdata	= pdata;
+	priv->pdev	= pdev;
+
+	priv->gc.owner			= THIS_MODULE;
+	priv->gc.parent			= &pdev->dev;
+	priv->gc.label			= dev_name(&pdev->dev);
+	priv->gc.ngpio			= priv->pdata->gpio_num;
+	priv->gc.names			= priv->pdata->gpio_names;
+	priv->gc.base			= -1;
+	priv->gc.request		= amd_fch_gpio_request;
+	priv->gc.direction_input	= amd_fch_gpio_direction_input;
+	priv->gc.direction_output	= amd_fch_gpio_direction_output;
+	priv->gc.get_direction		= amd_fch_gpio_get_direction;
+	priv->gc.get			= amd_fch_gpio_get;
+	priv->gc.set			= amd_fch_gpio_set;
+
+	spin_lock_init(&priv->lock);
+
+	priv->base = devm_ioremap_resource(&pdev->dev, &amd_fch_gpio_iores);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	platform_set_drvdata(pdev, priv);
+
+	return devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
+}
+
+static struct platform_driver amd_fch_gpio_driver = {
+	.driver = {
+		.name = AMD_FCH_GPIO_DRIVER_NAME,
+	},
+	.probe = amd_fch_gpio_probe,
+};
+
+module_platform_driver(amd_fch_gpio_driver);
+
+MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>");
+MODULE_DESCRIPTION("AMD G-series FCH GPIO driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" AMD_FCH_GPIO_DRIVER_NAME);