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>
diff --git a/drivers/gpio/gpio-amd8111.c b/drivers/gpio/gpio-amd8111.c
new file mode 100644
index 0000000..710fafc
--- /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");