i2c: Convert SCx200 driver from using raw PCI to platform device

The SCx200 ACB driver supports ISA hardware as well as PCI.  The PCI
hardware is CS5535/CS5536 based, and the device that it grabs is handled by
the cs5535-mfd driver. This converts the SCx200 driver to use a
platform_driver rather than the previous PCI hackery.

The driver used to manually track the iface list (via linked list); now it
only does this for ISA devices.  PCI ifaces are handled through standard
driver model lists.

It's unclear what happens in case of errors in the old ISA code; rather than
pretending the code actually cares, I've dropped the (implicit) ignorance
of return values and marked it with a comment.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 80 insertions, 120 deletions

diff --git a/drivers/i2c/busses/scx200_acb.c b/drivers/i2c/busses/scx200_acb.c
index 53fab518b3d..986e5f62deb 100644
--- a/drivers/i2c/busses/scx200_acb.c
+++ b/drivers/i2c/busses/scx200_acb.c
@@ -29,6 +29,7 @@
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/pci.h>
+#include <linux/platform_device.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
@@ -40,6 +41,7 @@
 
 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
+MODULE_ALIAS("platform:cs5535-smb");
 MODULE_LICENSE("GPL");
 
 #define MAX_DEVICES 4
@@ -84,10 +86,6 @@ struct scx200_acb_iface {
         u8 *ptr;
         char needs_reset;
         unsigned len;
-
-        /* PCI device info */
-        struct pci_dev *pdev;
-        int bar;
 };
 
 /* Register Definitions */
@@ -391,7 +389,7 @@ static const struct i2c_algorithm scx200_acb_algorithm = {
 static struct scx200_acb_iface *scx200_acb_list;
 static DEFINE_MUTEX(scx200_acb_list_mutex);
 
-static __init int scx200_acb_probe(struct scx200_acb_iface *iface)
+static __devinit int scx200_acb_probe(struct scx200_acb_iface *iface)
 {
         u8 val;
 
@@ -427,7 +425,7 @@ static __init int scx200_acb_probe(struct scx200_acb_iface *iface)
         return 0;
 }
 
-static __init struct scx200_acb_iface *scx200_create_iface(const char *text,
+static __devinit struct scx200_acb_iface *scx200_create_iface(const char *text,
                 struct device *dev, int index)
 {
         struct scx200_acb_iface *iface;
@@ -452,7 +450,7 @@ static __init struct scx200_acb_iface *scx200_create_iface(const char *text,
         return iface;
 }
 
-static int __init scx200_acb_create(struct scx200_acb_iface *iface)
+static int __devinit scx200_acb_create(struct scx200_acb_iface *iface)
 {
         struct i2c_adapter *adapter;
         int rc;
@@ -472,183 +470,145 @@ static int __init scx200_acb_create(struct scx200_acb_iface *iface)
                 return -ENODEV;
         }
 
-        mutex_lock(&scx200_acb_list_mutex);
-        iface->next = scx200_acb_list;
-        scx200_acb_list = iface;
-        mutex_unlock(&scx200_acb_list_mutex);
+        if (!adapter->dev.parent) {
+                /* If there's no dev, we're tracking (ISA) ifaces manually */
+                mutex_lock(&scx200_acb_list_mutex);
+                iface->next = scx200_acb_list;
+                scx200_acb_list = iface;
+                mutex_unlock(&scx200_acb_list_mutex);
+        }
 
         return 0;
 }
 
-static __init int scx200_create_pci(const char *text, struct pci_dev *pdev,
-                int bar)
+static struct scx200_acb_iface * __devinit scx200_create_dev(const char *text,
+                unsigned long base, int index, struct device *dev)
 {
         struct scx200_acb_iface *iface;
         int rc;
 
-        iface = scx200_create_iface(text, &pdev->dev, 0);
+        iface = scx200_create_iface(text, dev, index);
 
         if (iface == NULL)
-                return -ENOMEM;
-
-        iface->pdev = pdev;
-        iface->bar = bar;
-
-        rc = pci_enable_device_io(iface->pdev);
-        if (rc)
-                goto errout_free;
+                return NULL;
 
-        rc = pci_request_region(iface->pdev, iface->bar, iface->adapter.name);
-        if (rc) {
-                printk(KERN_ERR NAME ": can't allocate PCI BAR %d\n",
-                                iface->bar);
+        if (!request_region(base, 8, iface->adapter.name)) {
+                printk(KERN_ERR NAME ": can't allocate io 0x%lx-0x%lx\n",
+                       base, base + 8 - 1);
                 goto errout_free;
         }
 
-        iface->base = pci_resource_start(iface->pdev, iface->bar);
+        iface->base = base;
         rc = scx200_acb_create(iface);
 
         if (rc == 0)
-                return 0;
+                return iface;
 
-        pci_release_region(iface->pdev, iface->bar);
-        pci_dev_put(iface->pdev);
+        release_region(base, 8);
  errout_free:
         kfree(iface);
-        return rc;
+        return NULL;
 }
 
-static int __init scx200_create_isa(const char *text, unsigned long base,
-                int index)
+static int __devinit scx200_probe(struct platform_device *pdev)
 {
         struct scx200_acb_iface *iface;
-        int rc;
-
-        iface = scx200_create_iface(text, NULL, index);
-
-        if (iface == NULL)
-                return -ENOMEM;
+        struct resource *res;
 
-        if (!request_region(base, 8, iface->adapter.name)) {
-                printk(KERN_ERR NAME ": can't allocate io 0x%lx-0x%lx\n",
-                       base, base + 8 - 1);
-                rc = -EBUSY;
-                goto errout_free;
+        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "can't fetch device resource info\n");
+                return -ENODEV;
         }
 
-        iface->base = base;
-        rc = scx200_acb_create(iface);
+        iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev);
+        if (!iface)
+                return -EIO;
 
-        if (rc == 0)
-                return 0;
+        dev_info(&pdev->dev, "SCx200 device '%s' registered\n",
+                        iface->adapter.name);
+        platform_set_drvdata(pdev, iface);
 
-        release_region(base, 8);
- errout_free:
-        kfree(iface);
-        return rc;
+        return 0;
 }
 
-/* Driver data is an index into the scx200_data array that indicates
- * the name and the BAR where the I/O address resource is located.  ISA
- * devices are flagged with a bar value of -1 */
-
-static const struct pci_device_id scx200_pci[] __initconst = {
-        { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE),
-          .driver_data = 0 },
-        { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE),
-          .driver_data = 0 },
-        { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA),
-          .driver_data = 1 },
-        { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA),
-          .driver_data = 2 },
-        { 0, }
-};
-
-static struct {
-        const char *name;
-        int bar;
-} scx200_data[] = {
-        { "SCx200", -1 },
-        { "CS5535",  0 },
-        { "CS5536",  0 }
-};
+static void __devexit scx200_cleanup_iface(struct scx200_acb_iface *iface)
+{
+        i2c_del_adapter(&iface->adapter);
+        release_region(iface->base, 8);
+        kfree(iface);
+}
 
-static __init int scx200_scan_pci(void)
+static int __devexit scx200_remove(struct platform_device *pdev)
 {
-        int data, dev;
-        int rc = -ENODEV;
-        struct pci_dev *pdev;
+        struct scx200_acb_iface *iface;
 
-        for(dev = 0; dev < ARRAY_SIZE(scx200_pci); dev++) {
-                pdev = pci_get_device(scx200_pci[dev].vendor,
-                                scx200_pci[dev].device, NULL);
+        iface = platform_get_drvdata(pdev);
+        platform_set_drvdata(pdev, NULL);
+        scx200_cleanup_iface(iface);
 
-                if (pdev == NULL)
-                        continue;
+        return 0;
+}
 
-                data = scx200_pci[dev].driver_data;
+static struct platform_driver scx200_pci_drv = {
+        .driver = {
+                .name = "cs5535-smb",
+                .owner = THIS_MODULE,
+        },
+        .probe = scx200_probe,
+        .remove = __devexit_p(scx200_remove),
+};
 
-                /* if .bar is greater or equal to zero, this is a
-                 * PCI device - otherwise, we assume
-                   that the ports are ISA based
-                */
+static const struct pci_device_id scx200_isa[] __initconst = {
+        { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
+        { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
+        { 0, }
+};
 
-                if (scx200_data[data].bar >= 0)
-                        rc = scx200_create_pci(scx200_data[data].name, pdev,
-                                        scx200_data[data].bar);
-                else {
-                        int i;
+static __init void scx200_scan_isa(void)
+{
+        int i;
 
-                        pci_dev_put(pdev);
-                        for (i = 0; i < MAX_DEVICES; ++i) {
-                                if (base[i] == 0)
-                                        continue;
+        if (!pci_dev_present(scx200_isa))
+                return;
 
-                                rc = scx200_create_isa(scx200_data[data].name,
-                                                base[i],
-                                                i);
-                        }
-                }
+        for (i = 0; i < MAX_DEVICES; ++i) {
+                if (base[i] == 0)
+                        continue;
 
-                break;
+                /* XXX: should we care about failures? */
+                scx200_create_dev("SCx200", base[i], i, NULL);
         }
-
-        return rc;
 }
 
 static int __init scx200_acb_init(void)
 {
-        int rc;
-
         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 
-        rc = scx200_scan_pci();
+        /* First scan for ISA-based devices */
+        scx200_scan_isa();      /* XXX: should we care about errors? */
 
         /* If at least one bus was created, init must succeed */
         if (scx200_acb_list)
                 return 0;
-        return rc;
+
+        /* No ISA devices; register the platform driver for PCI-based devices */
+        return platform_driver_register(&scx200_pci_drv);
 }
 
 static void __exit scx200_acb_cleanup(void)
 {
         struct scx200_acb_iface *iface;
 
+        platform_driver_unregister(&scx200_pci_drv);
+
         mutex_lock(&scx200_acb_list_mutex);
         while ((iface = scx200_acb_list) != NULL) {
                 scx200_acb_list = iface->next;
                 mutex_unlock(&scx200_acb_list_mutex);
 
-                i2c_del_adapter(&iface->adapter);
-
-                if (iface->pdev) {
-                        pci_release_region(iface->pdev, iface->bar);
-                        pci_dev_put(iface->pdev);
-                }
-                else
-                        release_region(iface->base, 8);
+                scx200_cleanup_iface(iface);
 
-                kfree(iface);
                 mutex_lock(&scx200_acb_list_mutex);
         }
         mutex_unlock(&scx200_acb_list_mutex);