On 1 August 2011 22:25, Ben Dooks <ben-i2c@xxxxxxxxx> wrote:
> On Sun, Jul 31, 2011 at 02:21:27AM +0800, Shawn Guo wrote:
>> It adds device tree probe support for i2c-imx driver.
>>
>> Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
>> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
>> Cc: Darius Augulis <augulis.darius@xxxxxxxxx>
>> Cc: Ben Dooks <ben-linux@xxxxxxxxx>
>> Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
>> ---
>> .../devicetree/bindings/i2c/fsl-imx-i2c.txt | 25 ++++++++++++++++++++
>> drivers/i2c/busses/i2c-imx.c | 25 +++++++++++++++----
>> 2 files changed, 44 insertions(+), 6 deletions(-)
>> create mode 100644 Documentation/devicetree/bindings/i2c/fsl-imx-i2c.txt
>>
>> diff --git a/Documentation/devicetree/bindings/i2c/fsl-imx-i2c.txt b/Documentation/devicetree/bindings/i2c/fsl-imx-i2c.txt
>> new file mode 100644
>> index 0000000..f3cf43b
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/i2c/fsl-imx-i2c.txt
>> @@ -0,0 +1,25 @@
>> +* Freescale Inter IC (I2C) and High Speed Inter IC (HS-I2C) for i.MX
>> +
>> +Required properties:
>> +- compatible : Should be "fsl,<chip>-i2c"
>> +- reg : Should contain I2C/HS-I2C registers location and length
>> +- interrupts : Should contain I2C/HS-I2C interrupt
>> +
>> +Optional properties:
>> +- clock-frequency : Constains desired I2C/HS-I2C bus clock frequency in Hz.
>> + The absence of the propoerty indicates the default frequency 100 kHz.
>> +
>> +Examples:
>> +
>> +i2c@83fc4000 { /* I2C2 on i.MX51 */
>> + compatible = "fsl,imx51-i2c", "fsl,imx1-i2c";
>> + reg = <0x83fc4000 0x4000>;
>> + interrupts = <63>;
>> +};
>> +
>> +i2c@70038000 { /* HS-I2C on i.MX51 */
>> + compatible = "fsl,imx51-i2c", "fsl,imx1-i2c";
>> + reg = <0x70038000 0x4000>;
>> + interrupts = <64>;
>> + clock-frequency = <400000>;
>> +};
>
> It occurs to me that the clock-frequency field should be a standard
> used by all of-i2c drivers? could we have a standardised set of
> properties and a standard chunk of code that reads them?
>
Yes, "clock-frequency" is a common property for all clock frequency
binding, not only for of-i2c but all drivers that need to get clock
frequency from device tree. And it's a u32 and being read by the
common OF API of_property_read_u32(). So to answer your question,
both the binding and code have already been standard.
Regards,
Shawn
>> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
>> index 54d809e..58832e5 100644
>> --- a/drivers/i2c/busses/i2c-imx.c
>> +++ b/drivers/i2c/busses/i2c-imx.c
>> @@ -48,6 +48,9 @@
>> #include <linux/platform_device.h>
>> #include <linux/clk.h>
>> #include <linux/slab.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_i2c.h>
>>
>> #include <mach/irqs.h>
>> #include <mach/hardware.h>
>> @@ -125,6 +128,11 @@ struct imx_i2c_struct {
>> unsigned int ifdr; /* IMX_I2C_IFDR */
>> };
>>
>> +static const struct of_device_id i2c_imx_dt_ids[] = {
>> + { .compatible = "fsl,imx1-i2c", },
>> + { /* sentinel */ }
>> +};
>> +
>> /** Functions for IMX I2C adapter driver ***************************************
>> *******************************************************************************/
>>
>> @@ -469,7 +477,7 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
>> struct imxi2c_platform_data *pdata = pdev->dev.platform_data;
>> void __iomem *base;
>> resource_size_t res_size;
>> - int irq;
>> + int irq, bitrate;
>> int ret;
>>
>> dev_dbg(&pdev->dev, "<%s>\n", __func__);
>> @@ -512,6 +520,7 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
>> i2c_imx->adapter.algo = &i2c_imx_algo;
>> i2c_imx->adapter.dev.parent = &pdev->dev;
>> i2c_imx->adapter.nr = pdev->id;
>> + i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
>> i2c_imx->irq = irq;
>> i2c_imx->base = base;
>> i2c_imx->res = res;
>> @@ -538,10 +547,12 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
>> i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
>>
>> /* Set up clock divider */
>> - if (pdata && pdata->bitrate)
>> - i2c_imx_set_clk(i2c_imx, pdata->bitrate);
>> - else
>> - i2c_imx_set_clk(i2c_imx, IMX_I2C_BIT_RATE);
>> + bitrate = IMX_I2C_BIT_RATE;
>> + ret = of_property_read_u32(pdev->dev.of_node,
>> + "clock-frequency", &bitrate);
>> + if (ret < 0 && pdata && pdata->bitrate)
>> + bitrate = pdata->bitrate;
>> + i2c_imx_set_clk(i2c_imx, bitrate);
>>
>> /* Set up chip registers to defaults */
>> writeb(0, i2c_imx->base + IMX_I2C_I2CR);
>> @@ -554,6 +565,8 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
>> goto fail5;
>> }
>>
>> + of_i2c_register_devices(&i2c_imx->adapter);
>> +
>> /* Set up platform driver data */
>> platform_set_drvdata(pdev, i2c_imx);
>>
>> @@ -584,7 +597,6 @@ fail1:
>> static int __exit i2c_imx_remove(struct platform_device *pdev)
>> {
>> struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
>> - struct imxi2c_platform_data *pdata = pdev->dev.platform_data;
>>
>> /* remove adapter */
>> dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
>> @@ -613,6 +625,7 @@ static struct platform_driver i2c_imx_driver = {
>> .driver = {
>> .name = DRIVER_NAME,
>> .owner = THIS_MODULE,
>> + .of_match_table = i2c_imx_dt_ids,
>> }
>> };
>>
>> --
>> 1.7.4.1
>>
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