gpio: Add support for RDC321x GPIO controller

This patch adds a new GPIO driver for the RDC321x SoC GPIO controller.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 255 insertions, 1 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 4fd0f276df5a..56eb0c59c512 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -282,6 +282,14 @@ config GPIO_TIMBERDALE
         ---help---
         Add support for the GPIO IP in the timberdale FPGA.
 
+config GPIO_RDC321X
+        tristate "RDC R-321x GPIO support"
+        depends on PCI && GPIOLIB
+        select MFD_RDC321X
+        help
+          Support for the RDC R321x SoC GPIOs over southbridge
+          PCI configuration space.
+
 comment "SPI GPIO expanders:"
 
 config GPIO_MAX7301
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 10f3f8d958b1..d3226d395a90 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -27,4 +27,5 @@ obj-$(CONFIG_GPIO_VR41XX)	+= vr41xx_giu.o
 obj-$(CONFIG_GPIO_WM831X)       += wm831x-gpio.o
 obj-$(CONFIG_GPIO_WM8350)       += wm8350-gpiolib.o
 obj-$(CONFIG_GPIO_WM8994)       += wm8994-gpio.o
-obj-$(CONFIG_GPIO_SCH)          += sch_gpio.o
\ No newline at end of file
+obj-$(CONFIG_GPIO_SCH)          += sch_gpio.o
+obj-$(CONFIG_GPIO_RDC321X)      += rdc321x-gpio.o
diff --git a/drivers/gpio/rdc321x-gpio.c b/drivers/gpio/rdc321x-gpio.c
new file mode 100644
index 000000000000..46c55193b9db
--- /dev/null
+++ b/drivers/gpio/rdc321x-gpio.c
@@ -0,0 +1,245 @@
+/*
+ * RDC321x GPIO driver
+ *
+ * Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
+ * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/pci.h>
+#include <linux/gpio.h>
+#include <linux/mfd/rdc321x.h>
+
+struct rdc321x_gpio {
+        spinlock_t              lock;
+        struct pci_dev          *sb_pdev;
+        u32                     data_reg[2];
+        int                     reg1_ctrl_base;
+        int                     reg1_data_base;
+        int                     reg2_ctrl_base;
+        int                     reg2_data_base;
+        struct gpio_chip        chip;
+};
+
+/* read GPIO pin */
+static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+        struct rdc321x_gpio *gpch;
+        u32 value = 0;
+        int reg;
+
+        gpch = container_of(chip, struct rdc321x_gpio, chip);
+        reg = gpio < 32 ? gpch->reg1_data_base : gpch->reg2_data_base;
+
+        spin_lock(&gpch->lock);
+        pci_write_config_dword(gpch->sb_pdev, reg,
+                                        gpch->data_reg[gpio < 32 ? 0 : 1]);
+        pci_read_config_dword(gpch->sb_pdev, reg, &value);
+        spin_unlock(&gpch->lock);
+
+        return (1 << (gpio & 0x1f)) & value ? 1 : 0;
+}
+
+static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
+                                unsigned gpio, int value)
+{
+        struct rdc321x_gpio *gpch;
+        int reg = (gpio < 32) ? 0 : 1;
+
+        gpch = container_of(chip, struct rdc321x_gpio, chip);
+
+        if (value)
+                gpch->data_reg[reg] |= 1 << (gpio & 0x1f);
+        else
+                gpch->data_reg[reg] &= ~(1 << (gpio & 0x1f));
+
+        pci_write_config_dword(gpch->sb_pdev,
+                        reg ? gpch->reg1_data_base : gpch->reg2_data_base,
+                        gpch->data_reg[reg]);
+}
+
+/* set GPIO pin to value */
+static void rdc_gpio_set_value(struct gpio_chip *chip,
+                                unsigned gpio, int value)
+{
+        struct rdc321x_gpio *gpch;
+
+        gpch = container_of(chip, struct rdc321x_gpio, chip);
+        spin_lock(&gpch->lock);
+        rdc_gpio_set_value_impl(chip, gpio, value);
+        spin_unlock(&gpch->lock);
+}
+
+static int rdc_gpio_config(struct gpio_chip *chip,
+                                unsigned gpio, int value)
+{
+        struct rdc321x_gpio *gpch;
+        int err;
+        u32 reg;
+
+        gpch = container_of(chip, struct rdc321x_gpio, chip);
+
+        spin_lock(&gpch->lock);
+        err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ?
+                        gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, &reg);
+        if (err)
+                goto unlock;
+
+        reg |= 1 << (gpio & 0x1f);
+
+        err = pci_write_config_dword(gpch->sb_pdev, gpio < 32 ?
+                        gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, reg);
+        if (err)
+                goto unlock;
+
+        rdc_gpio_set_value_impl(chip, gpio, value);
+
+unlock:
+        spin_unlock(&gpch->lock);
+
+        return err;
+}
+
+/* configure GPIO pin as input */
+static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
+{
+        return rdc_gpio_config(chip, gpio, 1);
+}
+
+/*
+ * Cache the initial value of both GPIO data registers
+ */
+static int __devinit rdc321x_gpio_probe(struct platform_device *pdev)
+{
+        int err;
+        struct resource *r;
+        struct rdc321x_gpio *rdc321x_gpio_dev;
+        struct rdc321x_gpio_pdata *pdata;
+
+        pdata = pdev->dev.platform_data;
+        if (!pdata) {
+                dev_err(&pdev->dev, "no platform data supplied\n");
+                return -ENODEV;
+        }
+
+        rdc321x_gpio_dev = kzalloc(sizeof(struct rdc321x_gpio), GFP_KERNEL);
+        if (!rdc321x_gpio_dev) {
+                dev_err(&pdev->dev, "failed to allocate private data\n");
+                return -ENOMEM;
+        }
+
+        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gpio-reg1");
+        if (!r) {
+                dev_err(&pdev->dev, "failed to get gpio-reg1 resource\n");
+                err = -ENODEV;
+                goto out_free;
+        }
+
+        spin_lock_init(&rdc321x_gpio_dev->lock);
+        rdc321x_gpio_dev->sb_pdev = pdata->sb_pdev;
+        rdc321x_gpio_dev->reg1_ctrl_base = r->start;
+        rdc321x_gpio_dev->reg1_data_base = r->start + 0x4;
+
+        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gpio-reg2");
+        if (!r) {
+                dev_err(&pdev->dev, "failed to get gpio-reg2 resource\n");
+                err = -ENODEV;
+                goto out_free;
+        }
+
+        rdc321x_gpio_dev->reg2_ctrl_base = r->start;
+        rdc321x_gpio_dev->reg2_data_base = r->start + 0x4;
+
+        rdc321x_gpio_dev->chip.label = "rdc321x-gpio";
+        rdc321x_gpio_dev->chip.direction_input = rdc_gpio_direction_input;
+        rdc321x_gpio_dev->chip.direction_output = rdc_gpio_config;
+        rdc321x_gpio_dev->chip.get = rdc_gpio_get_value;
+        rdc321x_gpio_dev->chip.set = rdc_gpio_set_value;
+        rdc321x_gpio_dev->chip.base = 0;
+        rdc321x_gpio_dev->chip.ngpio = pdata->max_gpios;
+
+        platform_set_drvdata(pdev, rdc321x_gpio_dev);
+
+        /* This might not be, what others (BIOS, bootloader, etc.)
+           wrote to these registers before, but it's a good guess. Still
+           better than just using 0xffffffff. */
+        err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
+                                        rdc321x_gpio_dev->reg1_data_base,
+                                        &rdc321x_gpio_dev->data_reg[0]);
+        if (err)
+                goto out_drvdata;
+
+        err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
+                                        rdc321x_gpio_dev->reg2_data_base,
+                                        &rdc321x_gpio_dev->data_reg[1]);
+        if (err)
+                goto out_drvdata;
+
+        dev_info(&pdev->dev, "registering %d GPIOs\n",
+                                        rdc321x_gpio_dev->chip.ngpio);
+        return gpiochip_add(&rdc321x_gpio_dev->chip);
+
+out_drvdata:
+        platform_set_drvdata(pdev, NULL);
+out_free:
+        kfree(rdc321x_gpio_dev);
+        return err;
+}
+
+static int __devexit rdc321x_gpio_remove(struct platform_device *pdev)
+{
+        int ret;
+        struct rdc321x_gpio *rdc321x_gpio_dev = platform_get_drvdata(pdev);
+
+        ret = gpiochip_remove(&rdc321x_gpio_dev->chip);
+        if (ret)
+                dev_err(&pdev->dev, "failed to unregister chip\n");
+
+        kfree(rdc321x_gpio_dev);
+        platform_set_drvdata(pdev, NULL);
+
+        return ret;
+}
+
+static struct platform_driver rdc321x_gpio_driver = {
+        .driver.name    = "rdc321x-gpio",
+        .driver.owner   = THIS_MODULE,
+        .probe          = rdc321x_gpio_probe,
+        .remove         = __devexit_p(rdc321x_gpio_remove),
+};
+
+static int __init rdc321x_gpio_init(void)
+{
+        return platform_driver_register(&rdc321x_gpio_driver);
+}
+
+static void __exit rdc321x_gpio_exit(void)
+{
+        platform_driver_unregister(&rdc321x_gpio_driver);
+}
+
+module_init(rdc321x_gpio_init);
+module_exit(rdc321x_gpio_exit);
+
+MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
+MODULE_DESCRIPTION("RDC321x GPIO driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rdc321x-gpio");