[1/3] i2c: tegra: Support DVC controller in device tree

One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
block. This block is identical to the rest of the I2C blocks, except that
it only supports master mode, it has registers moved around, and it needs
some extra init to get it into I2C mode.  The register moves are handled
by i2c_readl and i2c_writel

This patch adds a new compatible value for controllers of this "DVC"
type; I figured that this approach was reasonable, as opposed to adding
an is-dvc property under the existing compatible value, since the HW
truly is different.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
Ben, it'd probably be simplest if you could ack this patch, and we
could take it through the Tegra tree.

 drivers/i2c/busses/i2c-tegra.c |   37 +++++++++++++++++++++++++------------
 1 files changed, 25 insertions(+), 12 deletions(-)

Hi,

On Sat, Dec 17, 2011 at 10:28:19PM -0700, Stephen Warren wrote:
> One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
> block. This block is identical to the rest of the I2C blocks, except that
> it only supports master mode, it has registers moved around, and it needs
> some extra init to get it into I2C mode.  The register moves are handled
> by i2c_readl and i2c_writel
> 
> This patch adds a new compatible value for controllers of this "DVC"
> type; I figured that this approach was reasonable, as opposed to adding
> an is-dvc property under the existing compatible value, since the HW
> truly is different.
> 
> Signed-off-by: Stephen Warren <swarren@nvidia.com>
> ---
> Ben, it'd probably be simplest if you could ack this patch, and we
> could take it through the Tegra tree.
> 
>  drivers/i2c/busses/i2c-tegra.c |   37 +++++++++++++++++++++++++------------
>  1 files changed, 25 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 46b6500..c264e8c 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -26,6 +26,7 @@
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/i2c-tegra.h>
> +#include <linux/of_device.h>
>  #include <linux/of_i2c.h>
>  #include <linux/module.h>
>  
> @@ -558,6 +559,18 @@ static const struct i2c_algorithm tegra_i2c_algo = {
>  	.functionality	= tegra_i2c_func,
>  };
>  
> +#if defined(CONFIG_OF)
> +/* Match table for of_platform binding */
> +static const struct of_device_id tegra_i2c_of_match[] __devinitconst = {
> +	{ .compatible = "nvidia,tegra20-i2c",     .data = (void *)0},
> +	{ .compatible = "nvidia,tegra20-i2c-dvc", .data = (void *)1},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
> +#else
> +#define tegra_i2c_of_match NULL
> +#endif
> +
>  static int tegra_i2c_probe(struct platform_device *pdev)
>  {
>  	struct tegra_i2c_dev *i2c_dev;
> @@ -636,7 +649,18 @@ static int tegra_i2c_probe(struct platform_device *pdev)
>  			i2c_dev->bus_clk_rate = be32_to_cpup(prop);
>  	}
>  
> -	if (pdev->id == 3)
> +#if defined(CONFIG_OF)
> +	if (pdev->dev.of_node) {
> +		const struct of_device_id *match;
> +
> +		match = of_match_device(tegra_i2c_of_match, &pdev->dev);
> +		if (!match)
> +			return -EINVAL;
> +
> +		i2c_dev->is_dvc = match->data;

I would rather see a:

		i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
						"nvidia,tegra20-i2c-dvc");

...instead of passing a flag through the match data.


-Olof
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* Stephen Warren wrote:
[...]
> @@ -636,7 +649,18 @@ static int tegra_i2c_probe(struct platform_device *pdev)
>  			i2c_dev->bus_clk_rate = be32_to_cpup(prop);
>  	}
>  
> -	if (pdev->id == 3)
> +#if defined(CONFIG_OF)
> +	if (pdev->dev.of_node) {
> +		const struct of_device_id *match;
> +
> +		match = of_match_device(tegra_i2c_of_match, &pdev->dev);
> +		if (!match)
> +			return -EINVAL;
> +
> +		i2c_dev->is_dvc = match->data;
> +	}
> +#endif
> +	else if (pdev->id == 3)

Shouldn't the "else" move into the CONFIG_OF branch?

Thierry

* Thierry Reding wrote:
> * Stephen Warren wrote:
> [...]
> > @@ -636,7 +649,18 @@ static int tegra_i2c_probe(struct platform_device *pdev)
> >  			i2c_dev->bus_clk_rate = be32_to_cpup(prop);
> >  	}
> >  
> > -	if (pdev->id == 3)
> > +#if defined(CONFIG_OF)
> > +	if (pdev->dev.of_node) {
> > +		const struct of_device_id *match;
> > +
> > +		match = of_match_device(tegra_i2c_of_match, &pdev->dev);
> > +		if (!match)
> > +			return -EINVAL;
> > +
> > +		i2c_dev->is_dvc = match->data;
> > +	}
> > +#endif
> > +	else if (pdev->id == 3)
> 
> Shouldn't the "else" move into the CONFIG_OF branch?

Okay, I hadn't seen v2. Please ignore.

Thierry