[PATCH 1/2] x86: gpio: AMD G-Series pch gpio platform driver

["Enrico Weigelt, metux IT consult" <info@metux.net>]

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.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
---
 MAINTAINERS                                        |   7 +
 drivers/gpio/Kconfig                               |  10 ++
 drivers/gpio/Makefile                              |   1 +
 drivers/gpio/gpio-amd-fch.c                        | 171 +++++++++++++++++++++
 .../linux/platform_data/x86/amd-fch-gpio-pdata.h   |  41 +++++
 5 files changed, 230 insertions(+)
 create mode 100644 drivers/gpio/gpio-amd-fch.c
 create mode 100644 include/linux/platform_data/x86/amd-fch-gpio-pdata.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 8c68de3c..a693f39 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -766,6 +766,13 @@ S:	Supported
 F:	Documentation/hwmon/fam15h_power
 F:	drivers/hwmon/fam15h_power.c
 
+AMD FCH GPIO DRIVER
+M:	Enrico Weigelt, metux IT consult <info@metux.net>
+L:	linux-gpio@vger.kernel.org
+S:	Maintanced
+F:	drivers/gpio/gpio-amd-fch.c
+F:	include/linux/platform_data/x86/amd-fch-gpio-pdata.h
+
 AMD GEODE CS5536 USB DEVICE CONTROLLER DRIVER
 L:	linux-geode@lists.infradead.org (moderated for non-subscribers)
 S:	Orphan
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b5a2845..a3e47c8 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -654,6 +654,16 @@ config GPIO_LOONGSON1
 	help
 	  Say Y or M here to support GPIO on Loongson1 SoCs.
 
+config GPIO_AMD_FCH
+	tristate "GPIO support for AMD Fusion Controller Hub (G-series SOCs)"
+	select GPIO_GENERIC
+	help
+	  This option enables driver for GPIO on AMDs Fusion Controller Hub,
+	  as found on G-series SOCs (eg. GX-412TC)
+
+	  Note: This driver doesn't registers itself automatically, as it
+	  needs to be provided with platform specific configuration.
+	  (See eg. CONFIG_PCENGINES_APU2.)
 endmenu
 
 menu "Port-mapped I/O GPIO drivers"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 37628f8..bb48fd2 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_GPIO_ADP5520)	+= gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)	+= gpio-adp5588.o
 obj-$(CONFIG_GPIO_ALTERA)  	+= gpio-altera.o
 obj-$(CONFIG_GPIO_ALTERA_A10SR)	+= gpio-altera-a10sr.o
+obj-$(CONFIG_GPIO_AMD_FCH)	+= gpio-amd-fch.o
 obj-$(CONFIG_GPIO_AMD8111)	+= gpio-amd8111.o
 obj-$(CONFIG_GPIO_AMDPT)	+= gpio-amdpt.o
 obj-$(CONFIG_GPIO_ARIZONA)	+= gpio-arizona.o
diff --git a/drivers/gpio/gpio-amd-fch.c b/drivers/gpio/gpio-amd-fch.c
new file mode 100644
index 0000000..8a002453
--- /dev/null
+++ b/drivers/gpio/gpio-amd-fch.c
@@ -0,0 +1,171 @@
+/*
+ * GPIO driver for the AMD G series FCH (eg. GX-412TC)
+ *
+ * Copyright (C) 2018 metux IT consult
+ * Author: Enrico Weigelt <info@metux.net>
+ *
+ * SPDX-License-Identifier: GPL+
+ */
+
+// FIXME: add spinlocks
+
+#include <linux/err.h>
+#include <linux/init.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/x86/amd-fch-gpio-pdata.h>
+
+
+#define GPIO_BIT_DIR		23
+#define GPIO_BIT_WRITE		22
+#define GPIO_BIT_READ		16
+
+
+struct amd_fch_gpio_priv {
+	struct platform_device		*pdev;
+	struct gpio_chip		gc;
+	void __iomem			*base;
+	struct amd_fch_gpio_pdata	*pdata;
+};
+
+static uint32_t *amd_fch_gpio_addr(struct gpio_chip *gc, unsigned gpio)
+{
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+
+	if (gpio > priv->pdata->gpio_num) {
+		dev_err(&priv->pdev->dev, "gpio number %d out of range\n", gpio);
+		return NULL;
+	}
+
+	return priv->base + priv->pdata->gpio_reg[gpio].reg*sizeof(u32);
+}
+
+static int amd_fch_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	volatile uint32_t *ptr = amd_fch_gpio_addr(gc, offset);
+	if (!ptr) return -EINVAL;
+
+	*ptr &= ~(1 << GPIO_BIT_DIR);
+	return 0;
+}
+
+static int amd_fch_gpio_direction_output(struct gpio_chip *gc, unsigned gpio, int value)
+{
+	volatile uint32_t *ptr = amd_fch_gpio_addr(gc, gpio);
+	if (!ptr) return -EINVAL;
+
+	*ptr |= (1 << GPIO_BIT_DIR);
+	return 0;
+}
+
+static int amd_fch_gpio_get_direction(struct gpio_chip *gc, unsigned gpio)
+{
+	volatile uint32_t *ptr = amd_fch_gpio_addr(gc, gpio);
+	if (!ptr) return -EINVAL;
+
+	return (*ptr >> GPIO_BIT_DIR) & 1;
+}
+
+static void amd_fch_gpio_set(struct gpio_chip *gc, unsigned gpio, int value)
+{
+	volatile uint32_t *ptr = amd_fch_gpio_addr(gc, gpio);
+	if (!ptr) return;
+
+	if (value)
+		*ptr |= (1 << GPIO_BIT_WRITE);
+	else
+		*ptr &= ~(1 << GPIO_BIT_WRITE);
+}
+
+static int amd_fch_gpio_get(struct gpio_chip *gc, unsigned offset)
+{
+	volatile uint32_t *ptr = amd_fch_gpio_addr(gc, offset);
+	if (!ptr) return -EINVAL;
+
+	return ((*ptr) >> GPIO_BIT_READ) & 1;
+}
+
+static void amd_fch_gpio_dbg_show(struct seq_file *s, struct gpio_chip *gc)
+{
+	struct amd_fch_gpio_priv *priv = gpiochip_get_data(gc);
+	(void)priv;
+
+	seq_printf(s, "debug info not implemented yet\n");
+}
+
+static int amd_fch_gpio_request(struct gpio_chip *chip, unsigned gpio_pin)
+{
+	if (gpio_pin < chip->ngpio)
+		return 0;
+
+	return -EINVAL;
+}
+
+static int amd_fch_gpio_probe(struct platform_device *pdev)
+{
+	struct amd_fch_gpio_priv *priv;
+	struct amd_fch_gpio_pdata *pdata = pdev->dev.platform_data;
+	int err;
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform_data\n");
+		return -ENOENT;
+	}
+
+	if (!(priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL))) {
+		dev_err(&pdev->dev, "failed to allocate priv struct\n");
+		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.base			= priv->pdata->gpio_base;
+	priv->gc.ngpio			= priv->pdata->gpio_num;
+	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->gc.bgpio_lock);
+
+	if (IS_ERR(priv->base = devm_ioremap_resource(&pdev->dev, &priv->pdata->res))) {
+		dev_err(&pdev->dev, "failed to map iomem\n");
+		return -ENXIO;
+	}
+
+	dev_info(&pdev->dev, "initializing on my own II\n");
+
+	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
+		dev_info(&pdev->dev, "enabling debugfs\n");
+		priv->gc.dbg_show = amd_fch_gpio_dbg_show;
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	err = devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
+	dev_info(&pdev->dev, "probe finished\n");
+	return err;
+}
+
+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:gpio_amd_fch");
diff --git a/include/linux/platform_data/x86/amd-fch-gpio-pdata.h b/include/linux/platform_data/x86/amd-fch-gpio-pdata.h
new file mode 100644
index 0000000..68c1730
--- /dev/null
+++ b/include/linux/platform_data/x86/amd-fch-gpio-pdata.h
@@ -0,0 +1,41 @@
+/*
+ * AMD FCH gpio driver platform-data
+ *
+ * Copyright (C) 2018 metux IT consult
+ * Author: Enrico Weigelt <info@metux.net>
+ *
+ * SPDX-License-Identifier: GPL
+ */
+
+#ifndef AMD_FCH_PDATA_H
+#define AMD_FCH_PDATA_H
+
+
+#include <linux/ioport.h>
+
+#define AMD_FCH_GPIO_DRIVER_NAME "gpio_amd_fch"
+
+/*
+ * struct amd_fch_gpio_reg - GPIO register definition
+ * @reg: register index
+ * @name: signal name
+ */
+struct amd_fch_gpio_reg {
+    int         reg;
+    const char* name;
+};
+
+/*
+ * struct amd_fch_gpio_pdata - GPIO chip platform data
+ * @resource: iomem range
+ * @gpio_reg: array of gpio registers
+ * @gpio_num: number of entries
+ */
+struct amd_fch_gpio_pdata {
+    struct resource          res;
+    int                      gpio_num;
+    struct amd_fch_gpio_reg *gpio_reg;
+    int                      gpio_base;
+};
+
+#endif /* AMD_FCH_PDATA_H */
-- 
1.9.1