[PATCH v2 1/2] i2c: xiic: Add OF support for Xilinx i2c bus interface

[Grant Likely]

On Tue, Feb 22, 2011 at 7:22 AM, Michal Simek <monstr at monstr.eu> wrote:
> Add OF support to Xilinx i2c bus interface.
> It is used on Microblaze systems.
>
> Signed-off-by: Michal Simek <monstr at monstr.eu>

Hi Michal, comments below...

> ---
>  drivers/i2c/busses/i2c-xiic.c |   46 ++++++++++++++++++++++++++++++++++------
>  1 files changed, 39 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c
> index a9c419e..4166570 100644
> --- a/drivers/i2c/busses/i2c-xiic.c
> +++ b/drivers/i2c/busses/i2c-xiic.c
> @@ -2,6 +2,8 @@
>  * i2c-xiic.c
>  * Copyright (c) 2002-2007 Xilinx Inc.
>  * Copyright (c) 2009-2010 Intel Corporation
> + * Copyright (c) 2010-2011 Michal Simek <monstr at monstr.eu>
> + * Copyright (c) 2010-2011 PetaLogix

This change is going to end up being pretty trivial.  It would be a
little odd to claim copyright on such a tiny change; particularly when
it just follows the pattern already established by other drivers.

>  *
>  * This program is free software; you can redistribute it and/or modify
>  * it under the terms of the GNU General Public License version 2 as
> @@ -41,6 +43,13 @@
>  #include <linux/io.h>
>  #include <linux/slab.h>
>
> +#ifdef CONFIG_OF
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_i2c.h>
> +#include <linux/of_address.h>
> +#endif

As previously mentioned; drop the #ifdef protection around these
includes. It should be safe to include them unconditionally, and if it
isn't then it is a bug in the headers which should be fixed.  These
includes should be part of the regular block of includes.

> +
>  #define DRIVER_NAME "xiic-i2c"
>
>  enum xilinx_i2c_state {
> @@ -426,7 +435,7 @@ static void xiic_process(struct xiic_i2c *i2c)
>                        xiic_wakeup(i2c, STATE_ERROR);
>
>        } else if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) {
> -               /* Transmit register/FIFO is empty or ½ empty */
> +               /* Transmit register/FIFO is empty or 1/2 empty */
>
>                clr = pend &
>                        (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK);
> @@ -691,10 +700,12 @@ static struct i2c_adapter xiic_adapter = {
>  static int __devinit xiic_i2c_probe(struct platform_device *pdev)
>  {
>        struct xiic_i2c *i2c;
> +#ifndef CONFIG_OF
>        struct xiic_i2c_platform_data *pdata;
> +       u8 i;
> +#endif
>        struct resource *res;
>        int ret, irq;
> -       u8 i;

You can drop this hunk (see below).

>
>        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>        if (!res)
> @@ -704,10 +715,6 @@ static int __devinit xiic_i2c_probe(struct platform_device *pdev)
>        if (irq < 0)
>                goto resource_missing;
>
> -       pdata = (struct xiic_i2c_platform_data *) pdev->dev.platform_data;
> -       if (!pdata)
> -               return -EINVAL;
> -
>        i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
>        if (!i2c)
>                return -ENOMEM;
> @@ -730,7 +737,9 @@ static int __devinit xiic_i2c_probe(struct platform_device *pdev)
>        i2c->adap = xiic_adapter;
>        i2c_set_adapdata(&i2c->adap, i2c);
>        i2c->adap.dev.parent = &pdev->dev;
> -
> +#ifdef CONFIG_OF
> +       i2c->adap.dev.of_node = of_node_get(pdev->dev.of_node);
> +#endif

Drop the #ifdef here.  In devicetree/next of_node is no longer
protected by a #ifdef.

>        xiic_reinit(i2c);
>
>        spin_lock_init(&i2c->lock);
> @@ -748,9 +757,20 @@ static int __devinit xiic_i2c_probe(struct platform_device *pdev)
>                goto add_adapter_failed;
>        }
>
> +       dev_info(&pdev->dev, "mapped to 0x%08X, irq=%d\n",
> +                                       (unsigned int)i2c->base, irq);
> +
> +#ifndef CONFIG_OF
> +       pdata = (struct xiic_i2c_platform_data *) pdev->dev.platform_data;
> +       if (!pdata)
> +               return -EINVAL;
> +
>        /* add in known devices to the bus */
>        for (i = 0; i < pdata->num_devices; i++)
>                i2c_new_device(&i2c->adap, pdata->devices + i);
> +#else
> +       of_i2c_register_devices(&i2c->adap);
> +#endif

Do it this way instead:

	pdata = (struct xiic_i2c_platform_data *) pdev->dev.platform_data;
	if (pdata) {
		/* add in known devices to the bus */
		for (i = 0; i < pdata->num_devices; i++)
		       i2c_new_device(&i2c->adap, pdata->devices + i);
	}

	of_i2c_register_devices(&i2c->adap);

of_i2c_register_devices() is safe to call regardless of if CONFIG_OF
is selected or not.  This driver should be written to handle both
device tree and platform_data use cases at run time.

>
>        return 0;
>
> @@ -799,12 +819,24 @@ static int __devexit xiic_i2c_remove(struct platform_device* pdev)
>  /* work with hotplug and coldplug */
>  MODULE_ALIAS("platform:"DRIVER_NAME);
>
> +#ifdef CONFIG_OF
> +/* Match table for of_platform binding */
> +static struct of_device_id __devinitdata xilinx_iic_of_match[] = {
> +       { .compatible = "xlnx,xps-iic-2.00.a", },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, xilinx_iic_of_match);

If you add the following, then you can drop the #ifdef around
.of_match_table below...

#else
#define xilinx_iic_of_match NULL

> +#endif
> +
>  static struct platform_driver xiic_i2c_driver = {
>        .probe   = xiic_i2c_probe,
>        .remove  = __devexit_p(xiic_i2c_remove),
>        .driver  = {
>                .owner = THIS_MODULE,
>                .name = DRIVER_NAME,
> +#ifdef CONFIG_OF
> +               .of_match_table = xilinx_iic_of_match,
> +#endif

Drop the #ifdef and base this patch on devicetree/next

>        },
>  };
>
> --
> 1.5.5.6
>
> --
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-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.