mfd: Add VIA VX855 multi-function device support

This device has GPIO, SPI and I2C capabilities.

The hardware can be found in the OLPC XO-1.5 laptop.

Based on earlier work by Harald Welte.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 157 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 256fabd7d65..9735f581574 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -576,6 +576,15 @@ config MFD_TPS6586X
           This driver can also be built as a module.  If so, the module
           will be called tps6586x.
 
+config MFD_VX855
+        tristate "Support for VIA VX855/VX875 integrated south bridge"
+        depends on PCI
+        select MFD_CORE
+        help
+          Say yes here to enable support for various functions of the
+          VIA VX855/VX875 south bridge. You will need to enable the vx855_spi
+          and/or vx855_gpio drivers for this to do anything useful.
+
 endif # MFD_SUPPORT
 
 menu "Multimedia Capabilities Port drivers"
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index d5968cd9304..d18a6ab2ab5 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -78,3 +78,4 @@ obj-$(CONFIG_MFD_RDC321X)	+= rdc321x-southbridge.o
 obj-$(CONFIG_MFD_JANZ_CMODIO)   += janz-cmodio.o
 obj-$(CONFIG_MFD_JZ4740_ADC)    += jz4740-adc.o
 obj-$(CONFIG_MFD_TPS6586X)      += tps6586x.o
+obj-$(CONFIG_MFD_VX855)         += vx855.o
diff --git a/drivers/mfd/vx855.c b/drivers/mfd/vx855.c
new file mode 100644
index 00000000000..ebb059765ed
--- /dev/null
+++ b/drivers/mfd/vx855.c
@@ -0,0 +1,147 @@
+/*
+ * Linux multi-function-device driver (MFD) for the integrated peripherals
+ * of the VIA VX855 chipset
+ *
+ * Copyright (C) 2009 VIA Technologies, Inc.
+ * Copyright (C) 2010 One Laptop per Child
+ * Author: Harald Welte <HaraldWelte@viatech.com>
+ * All rights reserved.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/pci.h>
+#include <linux/mfd/core.h>
+
+/* offset into pci config space indicating the 16bit register containing
+ * the power management IO space base */
+#define VX855_CFG_PMIO_OFFSET   0x88
+
+/* ACPI I/O Space registers */
+#define VX855_PMIO_ACPI         0x00
+#define VX855_PMIO_ACPI_LEN     0x0b
+
+/* Processor Power Management */
+#define VX855_PMIO_PPM          0x10
+#define VX855_PMIO_PPM_LEN      0x08
+
+/* General Purpose Power Management */
+#define VX855_PMIO_GPPM         0x20
+#define VX855_PMIO_R_GPI        0x48
+#define VX855_PMIO_R_GPO        0x4c
+#define VX855_PMIO_GPPM_LEN     0x33
+
+#define VSPIC_MMIO_SIZE 0x1000
+
+static struct resource vx855_gpio_resources[] = {
+        {
+                .flags = IORESOURCE_IO,
+        },
+        {
+                .flags = IORESOURCE_IO,
+        },
+};
+
+static struct mfd_cell vx855_cells[] = {
+        {
+                .name = "vx855_gpio",
+                .num_resources = ARRAY_SIZE(vx855_gpio_resources),
+                .resources = vx855_gpio_resources,
+
+                /* we must ignore resource conflicts, for reasons outlined in
+                 * the vx855_gpio driver */
+                .ignore_resource_conflicts = true,
+        },
+};
+
+static __devinit int vx855_probe(struct pci_dev *pdev,
+                                 const struct pci_device_id *id)
+{
+        int ret;
+        u16 gpio_io_offset;
+
+        ret = pci_enable_device(pdev);
+        if (ret)
+                return -ENODEV;
+
+        pci_read_config_word(pdev, VX855_CFG_PMIO_OFFSET, &gpio_io_offset);
+        if (!gpio_io_offset) {
+                dev_warn(&pdev->dev,
+                        "BIOS did not assign PMIO base offset?!?\n");
+                ret = -ENODEV;
+                goto out;
+        }
+
+        /* mask out the lowest seven bits, as they are always zero, but
+         * hardware returns them as 0x01 */
+        gpio_io_offset &= 0xff80;
+
+        /* As the region identified here includes many non-GPIO things, we
+         * only work with the specific registers that concern us. */
+        vx855_gpio_resources[0].start = gpio_io_offset + VX855_PMIO_R_GPI;
+        vx855_gpio_resources[0].end = vx855_gpio_resources[0].start + 3;
+        vx855_gpio_resources[1].start = gpio_io_offset + VX855_PMIO_R_GPO;
+        vx855_gpio_resources[1].end = vx855_gpio_resources[1].start + 3;
+
+        ret = mfd_add_devices(&pdev->dev, -1, vx855_cells, ARRAY_SIZE(vx855_cells),
+                        NULL, 0);
+
+        /* we always return -ENODEV here in order to enable other
+         * drivers like old, not-yet-platform_device ported i2c-viapro */
+        return -ENODEV;
+out:
+        pci_disable_device(pdev);
+        return ret;
+}
+
+static void vx855_remove(struct pci_dev *pdev)
+{
+        mfd_remove_devices(&pdev->dev);
+        pci_disable_device(pdev);
+}
+
+static struct pci_device_id vx855_pci_tbl[] = {
+        { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855) },
+        { 0, }
+};
+
+static struct pci_driver vx855_pci_driver = {
+        .name           = "vx855",
+        .id_table       = vx855_pci_tbl,
+        .probe          = vx855_probe,
+        .remove         = __devexit_p(vx855_remove),
+};
+
+static int vx855_init(void)
+{
+        return pci_register_driver(&vx855_pci_driver);
+}
+module_init(vx855_init);
+
+static void vx855_exit(void)
+{
+        pci_unregister_driver(&vx855_pci_driver);
+}
+module_exit(vx855_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
+MODULE_DESCRIPTION("Driver for the VIA VX855 chipset");