Subject: Re: [PATCH 2/2] i2c-ibm_iic driver

From: Jean Delvare <[email-masked]>
Date: Tue, 19 Feb 2008 09:23:21 +0100

Hi Sean,

On Mon, 18 Feb 2008 20:42:46 -0500, Sean MacLennan wrote:
> An updated version of the patch. This one should answer all of Jean's 
> concerns.
> 
> Cheers,
>    Sean
> 
> Signed-off-by: Sean MacLennan <[email-masked]>
> ---
> --- for-2.6.25/drivers/i2c/busses/orig-i2c-ibm_iic.c	2008-02-18 16:36:30.000000000 -0500
> +++ for-2.6.25/drivers/i2c/busses/i2c-ibm_iic.c	2008-02-18 17:39:53.000000000 -0500
> @@ -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");
> @@ -657,6 +665,7 @@
>  	return (u8)((opb + 9) / 10 - 1);
>  }
>  
> +#ifdef CONFIG_IBM_OCP
>  /*
>   * Register single IIC interface
>   */
> @@ -828,5 +837,182 @@
>  	ocp_unregister_driver(&ibm_iic_driver);
>  }
>  
> +#else  /* !CONFIG_IBM_OCP */
> +
> +static int __devinit iic_request_irq(struct of_device *ofdev,
> +				     struct ibm_iic_private *dev)
> +{
> +	struct device_node *np = ofdev->node;
> +	int irq;
> +
> +	if (iic_force_poll)
> +		return NO_IRQ;
> +
> +	irq = irq_of_parse_and_map(np, 0);
> +	if (irq == NO_IRQ) {
> +		dev_err(&ofdev->dev, "irq_of_parse_and_map failed\n");
> +		return NO_IRQ;
> +	}
> +
> +	/* Disable interrupts until we finish initialization, assumes
> +	 *  level-sensitive IRQ setup...
> +	 */
> +	iic_interrupt_mode(dev, 0);
> +	if (request_irq(irq, iic_handler, 0, "IBM IIC", dev)) {
> +		dev_err(&ofdev->dev, "request_irq %d failed\n", irq);
> +		/* Fallback to the polling mode */
> +		return NO_IRQ;
> +	}
> +
> +	return irq;
> +}
> +
> +/*
> + * Register single IIC interface
> + */
> +static int __devinit iic_probe(struct of_device *ofdev,
> +			       const struct of_device_id *match)
> +{
> +	struct device_node *np = ofdev->node;
> +	struct ibm_iic_private *dev;
> +	struct i2c_adapter *adap;
> +	const u32 *indexp, *freq;
> +	int ret;
> +
> +

Double blank line is prohibited inside a function.

> +	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> +	if (!dev) {
> +		dev_err(&ofdev->dev, "failed to allocate device data\n");
> +		return -ENOMEM;
> +	}
> +
> +	dev_set_drvdata(&ofdev->dev, dev);
> +
> +	indexp = of_get_property(np, "index", NULL);
> +	if (!indexp) {
> +		dev_err(&ofdev->dev, "no index specified.\n");

This is the only error message that has a trailing dot. Remove it?

> +		ret = -EINVAL;

Isn't it a bit inconsistent to return -EINVAL here...

> +		goto error_cleanup;
> +	}
> +	dev->idx = *indexp;
> +
> +	dev->vaddr = of_iomap(np, 0);
> +	if (dev->vaddr == NULL) {
> +		dev_err(&ofdev->dev, "failed to iomap device\n");
> +		ret = -ENXIO;
> +		goto error_cleanup;
> +	}
> +
> +	init_waitqueue_head(&dev->wq);
> +
> +	dev->irq = iic_request_irq(ofdev, dev);
> +	if (dev->irq == NO_IRQ)
> +		dev_warn(&ofdev->dev, "using polling mode\n");
> +
> +	/* Board specific settings */
> +	if (iic_force_fast || of_get_property(np, "fast-mode", NULL))
> +		dev->fast_mode = 1;
> +
> +	freq = of_get_property(np, "clock-frequency", NULL);
> +	if (freq == NULL) {
> +		freq = of_get_property(np->parent, "clock-frequency", NULL);
> +		if (freq == NULL) {
> +			dev_err(&ofdev->dev, "Unable to get bus frequency\n");
> +			ret = -EBUSY;

... but -EBUSY there?

> +			goto error_cleanup;
> +		}
> +	}
> +
> +	dev->clckdiv = iic_clckdiv(*freq);
> +	dev_dbg(&ofdev->dev, "clckdiv = %d\n", dev->clckdiv);
> +
> +	/* Initialize IIC interface */
> +	iic_dev_init(dev);
> +
> +	/* Register it with i2c layer */
> +	adap = &dev->adap;
> +	adap->dev.parent = &ofdev->dev;
> +	strlcpy(adap->name, "IBM IIC", sizeof(adap->name));
> +	i2c_set_adapdata(adap, dev);
> +	adap->id = I2C_HW_OCP;
> +	adap->class = I2C_CLASS_HWMON;
> +	adap->algo = &iic_algo;
> +	adap->timeout = 1;
> +	adap->nr = dev->idx;
> +
> +	ret = i2c_add_numbered_adapter(adap);
> +	if (ret  < 0) {
> +		dev_err(&ofdev->dev, "failed to register i2c adapter\n");
> +		goto error_cleanup;
> +	}
> +
> +	dev_dbg(&ofdev->dev, "using %s mode\n",

dev_info?

> +		dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
> +
> +	return 0;
> +
> +error_cleanup:
> +	if (dev->irq != NO_IRQ) {
> +		iic_interrupt_mode(dev, 0);
> +		free_irq(dev->irq, dev);
> +	}
> +
> +	if (dev->vaddr)
> +		iounmap(dev->vaddr);
> +
> +	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);
> +
> +	dev_set_drvdata(&ofdev->dev, NULL);
> +
> +	i2c_del_adapter(&dev->adap);
> +
> +	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[] = {
> +	{ .compatible = "ibm,iic-405ex", },
> +	{ .compatible = "ibm,iic-405gp", },
> +	{ .compatible = "ibm,iic-440gp", },
> +	{ .compatible = "ibm,iic-440gpx", },
> +	{ .compatible = "ibm,iic-440grx", },
> +	{}
> +};
> +
> +static struct of_platform_driver ibm_iic_driver = {
> +	.name	= "ibm-iic",
> +	.match_table = ibm_iic_match,
> +	.probe	= iic_probe,
> +	.remove	= __devexit_p(iic_remove),
> +};
> +
> +static int __init iic_init(void)
> +{
> +	return of_register_platform_driver(&ibm_iic_driver);
> +}
> +
> +static void __exit iic_exit(void)
> +{
> +	of_unregister_platform_driver(&ibm_iic_driver);
> +}
> +#endif /* CONFIG_IBM_OCP */
> +
>  module_init(iic_init);
>  module_exit(iic_exit);
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index b61f56b..44c0984 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -244,7 +244,6 @@ 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. 

With this Kconfig change, "make menuconfig" lets me select the
i2c-ibm_iic driver on x86_64, but it fails to build horribly. I think
that you want to restrict the build to PPC machines somehow, or at
least make sure that either IBM_OCP or OF support is present.

The rest looks fine to me. If you can address my last few comments, I
can push your 2 i2c-ibm_iic patches to -mm.

Thanks,
-- 
Jean Delvare