Re: [PATCH v4 5/7] ARM: davinci: i2c: add OF support

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On Tue, 22 May 2012 15:55:18 +0200, Heiko Schocher <hs@xxxxxxx> wrote:
> add of support for the davinci i2c driver.
> 
> Signed-off-by: Heiko Schocher <hs@xxxxxxx>
> Cc: davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
> Cc: linux-i2c@xxxxxxxxxxxxxxx
> Cc: Ben Dooks <ben-linux@xxxxxxxxx>
> Cc: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
> Cc: Sekhar Nori <nsekhar@xxxxxx>
> Cc: Wolfgang Denk <wd@xxxxxxx>
> Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> 
> ---
> - changes for v2:
> - add comments from Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>:
>   - use "cell-index" instead "id"
>   - OF_DEV_AUXDATA in the machine code, instead pre-define platform
>     device name
> - add comment from Grant Likely:
>   - removed "id" resp. "cell-index" completely
>   - fixed documentation
>   - use of_match_ptr()
>   - use devm_kzalloc() for allocating plattform data mem
>   - fixed a whitespace issue
> - no changes for v3
> - changes for v4
>   remove "pinmux-handle" property as discussed here:
>   http://www.spinics.net/lists/arm-kernel/msg175701.html
>   with Nori Sekhar
> ---
>  .../devicetree/bindings/arm/davinci/i2c.txt        |   31 +++++++++++++++++++
>  drivers/i2c/busses/i2c-davinci.c                   |   32 ++++++++++++++++++++
>  2 files changed, 63 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/arm/davinci/i2c.txt
> 
> diff --git a/Documentation/devicetree/bindings/arm/davinci/i2c.txt b/Documentation/devicetree/bindings/arm/davinci/i2c.txt
> new file mode 100644
> index 0000000..e98a025
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/davinci/i2c.txt
> @@ -0,0 +1,31 @@
> +* Texas Instruments Davinci I2C
> +
> +This file provides information, what the device node for the
> +davinci i2c interface contain.
> +
> +Required properties:
> +- compatible: "ti,davinci-i2c";
> +- reg : Offset and length of the register set for the device
> +
> +Recommended properties :
> +- interrupts : <a> standard interrupt property.
> +- clock-frequency : desired I2C bus clock frequency in Hz.
> +
> +Optional properties:
> +- bus-delay: bus delay in usec
> +
> +Example (enbw_cmc board):
> +	i2c@1c22000 {
> +		compatible = "ti,davinci-i2c";
> +		reg = <0x22000 0x1000>;
> +		clock-frequency = <100000>;
> +		interrupts = <15>;
> +		interrupt-parent = <&intc>;
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		dtt@48 {
> +				compatible = "national,lm75";
> +				reg = <0x48>;
> +			};
> +	};
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index a76d85f..c1783bb 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -38,9 +38,12 @@
>  #include <linux/slab.h>
>  #include <linux/cpufreq.h>
>  #include <linux/gpio.h>
> +#include <linux/of_i2c.h>
> +#include <linux/of_device.h>
>  
>  #include <mach/hardware.h>
>  #include <mach/i2c.h>
> +#include <mach/mux.h>
>  
>  /* ----- global defines ----------------------------------------------- */
>  
> @@ -635,6 +638,12 @@ static struct i2c_algorithm i2c_davinci_algo = {
>  	.functionality	= i2c_davinci_func,
>  };
>  
> +static const struct of_device_id davinci_i2c_of_match[] = {
> +	{.compatible = "ti,davinci-i2c", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
> +
>  static int davinci_i2c_probe(struct platform_device *pdev)
>  {
>  	struct davinci_i2c_dev *dev;
> @@ -676,6 +685,26 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>  	dev->irq = irq->start;
>  	platform_set_drvdata(pdev, dev);
>  
> +	if ((dev->dev->platform_data == NULL) &&
> +		(pdev->dev.of_node)) {
> +		struct davinci_i2c_platform_data *pdata;
> +		u32 prop;
> +
> +		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> +		if (!pdata) {
> +			r = -ENOMEM;
> +			goto err_free_mem;
> +		}
> +		memcpy(pdata, &davinci_i2c_platform_data_default,
> +			sizeof(*pdata));
> +		dev->dev->platform_data = pdata;

This is actually illegal.  Drivers must not change the value of
dev->dev->platform_data.  It messes up unbinding/rebinding drivers.
You'll need to have a copy of the pointer in davinci_i2c_dev.

Other than that this patch looks good.

g.

> +		if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
> +			&prop))
> +			pdata->bus_freq = prop / 1000;
> +		if (!of_property_read_u32(pdev->dev.of_node, "bus-delay",
> +			&prop))
> +			pdata->bus_delay = prop;
> +	}
>  	dev->clk = clk_get(&pdev->dev, NULL);
>  	if (IS_ERR(dev->clk)) {
>  		r = -ENODEV;
> @@ -711,6 +740,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>  	adap->algo = &i2c_davinci_algo;
>  	adap->dev.parent = &pdev->dev;
>  	adap->timeout = DAVINCI_I2C_TIMEOUT;
> +	adap->dev.of_node = pdev->dev.of_node;
>  
>  	adap->nr = pdev->id;
>  	r = i2c_add_numbered_adapter(adap);
> @@ -718,6 +748,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>  		dev_err(&pdev->dev, "failure adding adapter\n");
>  		goto err_free_irq;
>  	}
> +	of_i2c_register_devices(adap);
>  
>  	return 0;
>  
> @@ -809,6 +840,7 @@ static struct platform_driver davinci_i2c_driver = {
>  		.name	= "i2c_davinci",
>  		.owner	= THIS_MODULE,
>  		.pm	= davinci_i2c_pm_ops,
> +		.of_match_table = of_match_ptr(davinci_i2c_of_match),
>  	},
>  };
>  
> -- 
> 1.7.7.6
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.

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