gpio: add a driver for GPIO pins found on AMD-8111 south bridge chips

Add a driver to use GPIO pins available on several AMD south bridges
(currently only AMD 8111 is supported).

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 259 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c4067d0141f7..c2dfa9f90b47 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -466,6 +466,18 @@ config GPIO_BT8XX
 
           If unsure, say N.
 
+config GPIO_AMD8111
+        tristate "AMD 8111 GPIO driver"
+        depends on PCI
+        help
+          The AMD 8111 south bridge contains 32 GPIO pins which can be used.
+
+          Note, that usually system firmware/ACPI handles GPIO pins on their
+          own and users might easily break their systems with uncarefull usage
+          of this driver!
+
+          If unsure, say N
+
 config GPIO_LANGWELL
         bool "Intel Langwell/Penwell GPIO support"
         depends on PCI && X86
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 0f55662002c3..3a95b17dae86 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_GPIO_74X164)	+= gpio-74x164.o
 obj-$(CONFIG_GPIO_AB8500)       += gpio-ab8500.o
 obj-$(CONFIG_GPIO_ADP5520)      += gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)      += gpio-adp5588.o
+obj-$(CONFIG_GPIO_AMD8111)      += gpio-amd8111.o
 obj-$(CONFIG_GPIO_BT8XX)        += gpio-bt8xx.o
 obj-$(CONFIG_GPIO_CS5535)       += gpio-cs5535.o
 obj-$(CONFIG_GPIO_DA9052)       += gpio-da9052.o
diff --git a/drivers/gpio/gpio-amd8111.c b/drivers/gpio/gpio-amd8111.c
new file mode 100644
index 000000000000..710fafcdd1b1
--- /dev/null
+++ b/drivers/gpio/gpio-amd8111.c
@@ -0,0 +1,246 @@
+/*
+ * GPIO driver for AMD 8111 south bridges
+ *
+ * Copyright (c) 2012 Dmitry Eremin-Solenikov
+ *
+ * Based on the AMD RNG driver:
+ * Copyright 2005 (c) MontaVista Software, Inc.
+ * with the majority of the code coming from:
+ *
+ * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
+ * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
+ *
+ * derived from
+ *
+ * Hardware driver for the AMD 768 Random Number Generator (RNG)
+ * (c) Copyright 2001 Red Hat Inc
+ *
+ * derived from
+ *
+ * Hardware driver for Intel i810 Random Number Generator (RNG)
+ * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
+ * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
+ *
+ * This file is licensed under  the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/gpio.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+
+#define PMBASE_OFFSET 0xb0
+#define PMBASE_SIZE   0x30
+
+#define AMD_REG_GPIO(i) (0x10 + (i))
+
+#define AMD_GPIO_LTCH_STS       0x40 /* Latch status, w1 */
+#define AMD_GPIO_RTIN           0x20 /* Real Time in, ro */
+#define AMD_GPIO_DEBOUNCE       0x10 /* Debounce, rw */
+#define AMD_GPIO_MODE_MASK      0x0c /* Pin Mode Select, rw */
+#define AMD_GPIO_MODE_IN        0x00
+#define AMD_GPIO_MODE_OUT       0x04
+/* Enable alternative (e.g. clkout, IRQ, etc) function of the pin */
+#define AMD_GPIO_MODE_ALTFN     0x08 /* Or 0x09 */
+#define AMD_GPIO_X_MASK         0x03 /* In/Out specific, rw */
+#define AMD_GPIO_X_IN_ACTIVEHI  0x01 /* Active High */
+#define AMD_GPIO_X_IN_LATCH     0x02 /* Latched version is selected */
+#define AMD_GPIO_X_OUT_LOW      0x00
+#define AMD_GPIO_X_OUT_HI       0x01
+#define AMD_GPIO_X_OUT_CLK0     0x02
+#define AMD_GPIO_X_OUT_CLK1     0x03
+
+/*
+ * Data for PCI driver interface
+ *
+ * This data only exists for exporting the supported
+ * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
+ * register a pci_driver, because someone else might one day
+ * want to register another driver on the same PCI id.
+ */
+static DEFINE_PCI_DEVICE_TABLE(pci_tbl) = {
+        { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8111_SMBUS), 0 },
+        { 0, }, /* terminate list */
+};
+MODULE_DEVICE_TABLE(pci, pci_tbl);
+
+struct amd_gpio {
+        struct gpio_chip        chip;
+        u32                     pmbase;
+        void __iomem            *pm;
+        struct pci_dev          *pdev;
+        spinlock_t              lock; /* guards hw registers and orig table */
+        u8                      orig[32];
+};
+
+#define to_agp(chip)    container_of(chip, struct amd_gpio, chip)
+
+static int amd_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+        struct amd_gpio *agp = to_agp(chip);
+
+        agp->orig[offset] = ioread8(agp->pm + AMD_REG_GPIO(offset)) &
+                (AMD_GPIO_DEBOUNCE | AMD_GPIO_MODE_MASK | AMD_GPIO_X_MASK);
+
+        dev_dbg(&agp->pdev->dev, "Requested gpio %d, data %x\n", offset, agp->orig[offset]);
+
+        return 0;
+}
+
+static void amd_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+        struct amd_gpio *agp = to_agp(chip);
+
+        dev_dbg(&agp->pdev->dev, "Freed gpio %d, data %x\n", offset, agp->orig[offset]);
+
+        iowrite8(agp->orig[offset], agp->pm + AMD_REG_GPIO(offset));
+}
+
+static void amd_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+        struct amd_gpio *agp = to_agp(chip);
+        u8 temp;
+        unsigned long flags;
+
+        spin_lock_irqsave(&agp->lock, flags);
+        temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
+        temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_OUT | (value ? AMD_GPIO_X_OUT_HI : AMD_GPIO_X_OUT_LOW);
+        iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
+        spin_unlock_irqrestore(&agp->lock, flags);
+
+        dev_dbg(&agp->pdev->dev, "Setting gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
+}
+
+static int amd_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+        struct amd_gpio *agp = to_agp(chip);
+        u8 temp;
+
+        temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
+
+        dev_dbg(&agp->pdev->dev, "Getting gpio %d, reg=%02x\n", offset, temp);
+
+        return (temp & AMD_GPIO_RTIN) ? 1 : 0;
+}
+
+static int amd_gpio_dirout(struct gpio_chip *chip, unsigned offset, int value)
+{
+        struct amd_gpio *agp = to_agp(chip);
+        u8 temp;
+        unsigned long flags;
+
+        spin_lock_irqsave(&agp->lock, flags);
+        temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
+        temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_OUT | (value ? AMD_GPIO_X_OUT_HI : AMD_GPIO_X_OUT_LOW);
+        iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
+        spin_unlock_irqrestore(&agp->lock, flags);
+
+        dev_dbg(&agp->pdev->dev, "Dirout gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
+
+        return 0;
+}
+
+static int amd_gpio_dirin(struct gpio_chip *chip, unsigned offset)
+{
+        struct amd_gpio *agp = to_agp(chip);
+        u8 temp;
+        unsigned long flags;
+
+        spin_lock_irqsave(&agp->lock, flags);
+        temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
+        temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_IN;
+        iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
+        spin_unlock_irqrestore(&agp->lock, flags);
+
+        dev_dbg(&agp->pdev->dev, "Dirin gpio %d, reg=%02x\n", offset, temp);
+
+        return 0;
+}
+
+static struct amd_gpio gp = {
+        .chip = {
+                .label          = "AMD GPIO",
+                .owner          = THIS_MODULE,
+                .base           = -1,
+                .ngpio          = 32,
+                .request        = amd_gpio_request,
+                .free           = amd_gpio_free,
+                .set            = amd_gpio_set,
+                .get            = amd_gpio_get,
+                .direction_output = amd_gpio_dirout,
+                .direction_input = amd_gpio_dirin,
+        },
+};
+
+static int __init amd_gpio_init(void)
+{
+        int err = -ENODEV;
+        struct pci_dev *pdev = NULL;
+        const struct pci_device_id *ent;
+
+
+        /* We look for our device - AMD South Bridge
+         * I don't know about a system with two such bridges,
+         * so we can assume that there is max. one device.
+         *
+         * We can't use plain pci_driver mechanism,
+         * as the device is really a multiple function device,
+         * main driver that binds to the pci_device is an smbus
+         * driver and have to find & bind to the device this way.
+         */
+        for_each_pci_dev(pdev) {
+                ent = pci_match_id(pci_tbl, pdev);
+                if (ent)
+                        goto found;
+        }
+        /* Device not found. */
+        goto out;
+
+found:
+        err = pci_read_config_dword(pdev, 0x58, &gp.pmbase);
+        if (err)
+                goto out;
+        err = -EIO;
+        gp.pmbase &= 0x0000FF00;
+        if (gp.pmbase == 0)
+                goto out;
+        if (!request_region(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE, "AMD GPIO")) {
+                dev_err(&pdev->dev, "AMD GPIO region 0x%x already in use!\n",
+                        gp.pmbase + PMBASE_OFFSET);
+                err = -EBUSY;
+                goto out;
+        }
+        gp.pm = ioport_map(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+        gp.pdev = pdev;
+        gp.chip.dev = &pdev->dev;
+
+        spin_lock_init(&gp.lock);
+
+        printk(KERN_INFO "AMD-8111 GPIO detected\n");
+        err = gpiochip_add(&gp.chip);
+        if (err) {
+                printk(KERN_ERR "GPIO registering failed (%d)\n",
+                       err);
+                release_region(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+                goto out;
+        }
+out:
+        return err;
+}
+
+static void __exit amd_gpio_exit(void)
+{
+        int err = gpiochip_remove(&gp.chip);
+        WARN_ON(err);
+        ioport_unmap(gp.pm);
+        release_region(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE);
+}
+
+module_init(amd_gpio_init);
+module_exit(amd_gpio_exit);
+
+MODULE_AUTHOR("The Linux Kernel team");
+MODULE_DESCRIPTION("GPIO driver for AMD chipsets");
+MODULE_LICENSE("GPL");