On 1 August 2011 22:25, Ben Dooks [off-list ref] wrote:

On Sun, Jul 31, 2011 at 02:21:27AM +0800, Shawn Guo wrote:

quoted

It adds device tree probe support for i2c-imx driver.

Signed-off-by: Shawn Guo <redacted>
Cc: Grant Likely <redacted>
Cc: Darius Augulis <redacted>
Cc: Ben Dooks <ben-linux@fluff.org>
Acked-by: Grant Likely <redacted>
---
?.../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 at 83fc4000 { /* I2C2 on i.MX51 */
+ ? ? compatible = "fsl,imx51-i2c", "fsl,imx1-i2c";
+ ? ? reg = <0x83fc4000 0x4000>;
+ ? ? interrupts = <63>;
+};
+
+i2c at 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

quoted

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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