Subject: Re: [PATCH] i2c-ibm_iic driver - new patch

From: Sean MacLennan <[email-masked]>
Date: Tue, 08 Jan 2008 00:56:27 -0500

Stephen Rothwell wrote:
> Hi Sean,
>
> On Mon, 07 Jan 2008 21:03:12 -0500 Sean MacLennan <[email-masked]> wrote:
>   
>
> Please don't post patches as attachments.
>   
Ok.
>   
>> +static int __devinit iic_probe(struct of_device *ofdev,
>> +							   const struct of_device_id *match)
>>     
>
> Indenting could be better.
>   
Sorry. Since this kernel is in a "work" directory and not in 
/usr/src/linux* my rules for deciding on the tab size didn't work :( I 
tried to correct the tabbing.
> Please split the assignments from the tests.  Here and elsewhere.
>
>   
I made the changes in my code. I am trying to leave the original code as 
much as possible.
>> +		printk(KERN_CRIT "ibm-iic: failed to allocate device data\n");
>>     
>
> I am not sure that these messages are necessary and, even if so, not KERN_CRIT.
>
>   
What would you recommend then? KERN_ERR? These are cut and paste from 
the original driver, so I left them alone. I will try KERN_ERR.
>> +		}
>> +	} else {
>> +		if (dev->irq != NO_IRQ){
>> +		    iic_interrupt_mode(dev, 0);
>> +		    free_irq(dev->irq, dev);
>> +		}
>> +		iounmap(dev->vaddr);
>> +		kfree(dev);
>>     
>
> Should these last two be after the below brace?
>
>   
I'm not really qualified to answer, but I will anyway ;) I assume the 
original author is basically saying if he cannot delete the adapter, it 
is unsafe to free the memory since the i2c code may still use it. If I 
have read that right, then I agree.

Cheers,
    Sean

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index c466c6c..e9e1493 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -241,7 +241,6 @@ config I2C_PIIX4
 
 config I2C_IBM_IIC
     tristate "IBM PPC 4xx on-chip I2C interface"
-    depends on IBM_OCP
     help
       Say Y here if you want to use IIC peripheral found on
       embedded IBM PPC 4xx based systems.
diff --git a/drivers/i2c/busses/i2c-ibm_iic.c 
b/drivers/i2c/busses/i2c-ibm_iic.c
index 9b43ff7..d218a3b 100644
--- a/drivers/i2c/busses/i2c-ibm_iic.c
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@@ -6,6 +6,9 @@
  * Copyright (c) 2003, 2004 Zultys Technologies.
  * Eugene Surovegin <[email-masked]> or <[email-masked]>
  *
+ * Copyright (c) 2008 PIKA Technologies
+ * Sean MacLennan <[email-masked]>
+ *
  * Based on original work by
  *     Ian DaSilva  <[email-masked]>
  *      Armin Kuster <[email-masked]>
@@ -39,12 +42,17 @@
 #include <asm/io.h>
 #include <linux/i2c.h>
 #include <linux/i2c-id.h>
+
+#ifdef CONFIG_IBM_OCP
 #include <asm/ocp.h>
 #include <asm/ibm4xx.h>
+#else
+#include <linux/of_platform.h>
+#endif
 
 #include "i2c-ibm_iic.h"
 
-#define DRIVER_VERSION "2.1"
+#define DRIVER_VERSION "2.2"
 
 MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION);
 MODULE_LICENSE("GPL");
@@ -650,13 +658,14 @@ static inline u8 iic_clckdiv(unsigned int opb)
     opb /= 1000000;
    
     if (opb < 20 || opb > 150){
-        printk(KERN_CRIT "ibm-iic: invalid OPB clock frequency %u MHz\n",
+        printk(KERN_WARNING "ibm-iic: invalid OPB clock frequency %u 
MHz\n",
             opb);
         opb = opb < 20 ? 20 : 150;
     }
     return (u8)((opb + 9) / 10 - 1);
 }
 
+#ifdef CONFIG_IBM_OCP
 /*
  * Register single IIC interface
  */
@@ -672,7 +681,7 @@ static int __devinit iic_probe(struct ocp_device *ocp){
             ocp->def->index);
 
     if (!(dev = kzalloc(sizeof(*dev), GFP_KERNEL))) {
-        printk(KERN_CRIT "ibm-iic%d: failed to allocate device data\n",
+        printk(KERN_ERR "ibm-iic%d: failed to allocate device data\n",
             ocp->def->index);
         return -ENOMEM;
     }
@@ -687,7 +696,7 @@ static int __devinit iic_probe(struct ocp_device *ocp){
     }
 
     if (!(dev->vaddr = ioremap(ocp->def->paddr, sizeof(struct iic_regs)))){
-        printk(KERN_CRIT "ibm-iic%d: failed to ioremap device registers\n",
+        printk(KERN_ERR "ibm-iic%d: failed to ioremap device registers\n",
             dev->idx);
         ret = -ENXIO;
         goto fail2;
@@ -746,7 +755,7 @@ static int __devinit iic_probe(struct ocp_device *ocp){
     adap->nr = dev->idx >= 0 ? dev->idx : 0;
 
     if ((ret = i2c_add_numbered_adapter(adap)) < 0) {
-        printk(KERN_CRIT "ibm-iic%d: failed to register i2c adapter\n",
+        printk(KERN_ERR "ibm-iic%d: failed to register i2c adapter\n",
             dev->idx);
         goto fail;
     }
@@ -779,7 +788,7 @@ static void __devexit iic_remove(struct ocp_device *ocp)
     struct ibm_iic_private* dev = (struct 
ibm_iic_private*)ocp_get_drvdata(ocp);
     BUG_ON(dev == NULL);
     if (i2c_del_adapter(&dev->adap)){
-        printk(KERN_CRIT "ibm-iic%d: failed to delete i2c adapter :(\n",
+        printk(KERN_ERR "ibm-iic%d: failed to delete i2c adapter :(\n",
             dev->idx);
         /* That's *very* bad, just shutdown IRQ ... */
         if (dev->irq >= 0){
@@ -831,3 +840,186 @@ static void __exit iic_exit(void)
 
 module_init(iic_init);
 module_exit(iic_exit);
+#else
+/*
+ * Register single IIC interface
+ */
+static int __devinit iic_probe(struct of_device *ofdev,
+                   const struct of_device_id *match)
+{
+    static int index = 0;
+    struct device_node *np = ofdev->node;
+    struct ibm_iic_private* dev;
+    struct i2c_adapter* adap;
+    const u32 *indexp, *freq;
+    int ret;
+
+    dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+    if (!dev) {
+        printk(KERN_ERR "ibm-iic: failed to allocate device data\n");
+        return -ENOMEM;
+    }
+
+    /* This assumes we don't mix index and non-index entries. */
+    indexp = of_get_property(np, "index", NULL);
+    dev->idx = indexp ? *indexp : index++;
+
+    dev_set_drvdata(&ofdev->dev, dev);
+
+    dev->vaddr = of_iomap(np, 0);
+    if (dev->vaddr == NULL) {
+        printk(KERN_ERR "ibm-iic%d: failed to ioremap device registers\n",
+            dev->idx);
+        ret = -ENXIO;
+        goto fail1;
+    }
+
+    init_waitqueue_head(&dev->wq);
+
+    if (iic_force_poll)
+        dev->irq = NO_IRQ;
+    else if ((dev->irq = irq_of_parse_and_map(np, 0)) == NO_IRQ)
+        printk(KERN_ERR __FILE__ ": irq_of_parse_and_map failed\n");
+    else {
+        /* Disable interrupts until we finish initialization,
+           assumes level-sensitive IRQ setup...
+         */
+        iic_interrupt_mode(dev, 0);
+        if (request_irq(dev->irq, iic_handler, 0, "IBM IIC", dev)){
+            printk(KERN_ERR "ibm-iic%d: request_irq %d failed\n",
+                   dev->idx, dev->irq);
+            /* Fallback to the polling mode */
+            dev->irq = NO_IRQ;
+        }
+    }
+
+    if (dev->irq == NO_IRQ)
+        printk(KERN_WARNING "ibm-iic%d: using polling mode\n",
+               dev->idx);
+
+    /* Board specific settings */
+    if (iic_force_fast || of_get_property(np, "fast-mode", NULL))
+        dev->fast_mode = 1;
+    else
+        dev->fast_mode = 0;
+
+    /* clckdiv is the same for *all* IIC interfaces, but I'd rather
+     * make a copy than introduce another global. --ebs
+     */
+    freq = of_get_property(np, "clock-frequency", NULL);
+    if (freq == NULL) {
+        freq = of_get_property(np->parent, "clock-frequency", NULL);
+        if (freq == NULL) {
+            printk(KERN_ERR "ibm-iic%d: Unable to get bus frequency\n",
+                   dev->idx);
+            ret = -EBUSY;
+            goto fail;
+        }
+    }
+
+    dev->clckdiv = iic_clckdiv(*freq);
+    DBG("%d: clckdiv = %d\n", dev->idx, dev->clckdiv);
+
+    /* Initialize IIC interface */
+    iic_dev_init(dev);
+
+    /* Register it with i2c layer */
+    adap = &dev->adap;
+    adap->dev.parent = &ofdev->dev;
+    strcpy(adap->name, "IBM IIC");
+    i2c_set_adapdata(adap, dev);
+    adap->id = I2C_HW_OCP;
+    adap->class = I2C_CLASS_HWMON;
+    adap->algo = &iic_algo;
+    adap->client_register = NULL;
+    adap->client_unregister = NULL;
+    adap->timeout = 1;
+    adap->retries = 1;
+    adap->nr = dev->idx;
+
+    ret = i2c_add_numbered_adapter(adap);
+    if (ret  < 0) {
+        printk(KERN_ERR "ibm-iic%d: failed to register i2c adapter\n",
+            dev->idx);
+        goto fail;
+    }
+
+    printk(KERN_INFO "ibm-iic%d: using %s mode\n", dev->idx,
+        dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
+
+    return 0;
+
+fail:
+    if (dev->irq != NO_IRQ){
+        iic_interrupt_mode(dev, 0);
+        free_irq(dev->irq, dev);
+    }
+
+    iounmap(dev->vaddr);
+fail1:
+    dev_set_drvdata(&ofdev->dev, NULL);
+    kfree(dev);
+    return ret;
+}
+
+/*
+ * Cleanup initialized IIC interface
+ */
+static int __devexit iic_remove(struct of_device *ofdev)
+{
+    struct ibm_iic_private* dev = dev_get_drvdata(&ofdev->dev);
+
+    BUG_ON(dev == NULL);
+    if (i2c_del_adapter(&dev->adap)){
+        printk(KERN_ERR "ibm-iic%d: failed to delete i2c adapter :(\n",
+            dev->idx);
+        /* That's *very* bad, just shutdown IRQ ... */
+        if (dev->irq != NO_IRQ){
+            iic_interrupt_mode(dev, 0);
+            free_irq(dev->irq, dev);
+            dev->irq = NO_IRQ;
+        }
+    } else {
+        if (dev->irq != NO_IRQ){
+            iic_interrupt_mode(dev, 0);
+            free_irq(dev->irq, dev);
+        }
+        iounmap(dev->vaddr);
+        kfree(dev);
+    }
+
+    return 0;
+}
+
+
+static const struct of_device_id ibm_iic_match[] =
+{
+    { .type = "i2c", .compatible = "ibm,iic-405ex", },
+    { .type = "i2c", .compatible = "ibm,iic-405gp", },
+    { .type = "i2c", .compatible = "ibm,iic-440gp", },
+    { .type = "i2c", .compatible = "ibm,iic-440gpx", },
+    { .type = "i2c", .compatible = "ibm,iic-440grx", },
+    {}
+};
+
+static struct of_platform_driver ibm_iic_driver =
+{
+    .name   = "ibm-iic",
+    .match_table = ibm_iic_match,
+    .probe  = iic_probe,
+    .remove = iic_remove,
+};
+
+static int __init ibm_iic_init(void)
+{
+    printk(KERN_INFO "IBM IIC driver v" DRIVER_VERSION "\n");
+    return of_register_platform_driver(&ibm_iic_driver);
+}
+module_init(ibm_iic_init);
+
+static void __exit ibm_iic_exit(void)
+{
+    of_unregister_platform_driver(&ibm_iic_driver);
+}
+module_exit(ibm_iic_exit);
+#endif