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

Hello Grant,

Grant Likely wrote:

On Mon, Jan 23, 2012 at 09:56:05AM +0100, Heiko Schocher wrote:

quoted

add of support for the davinci i2c driver.

Signed-off-by: Heiko Schocher <redacted>
Cc: davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Ben Dooks <redacted>
Cc: Wolfram Sang <redacted>
Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: Sekhar Nori <redacted>
Cc: Wolfgang Denk <redacted>

Hi Heiko,

comments below.

Thanks!

quoted

---
 .../devicetree/bindings/arm/davinci/i2c.txt        |   39 ++++++++++++++++++
 drivers/i2c/busses/i2c-davinci.c                   |   43 ++++++++++++++++++++
 2 files changed, 82 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..94ec670
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/davinci/i2c.txt

@@ -0,0 +1,39 @@
+* 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
+- id: id of the controller

Don't use an 'id' property.  i2c bus numbers should be dynamically
assigned when using the device tree.

Yep, removed!

quoted

+
+Recommended properties :
+- interrupts : <a b> where a is the interrupt number and b is a
+  field that represents an encoding of the sense and level
+  information for the interrupt.

This is inaccurate.  It is entirely defined by the interrupt
controller.  All you need to say here is that this is a standard
interrupts property.

fixed.

quoted

+- interrupt-parent : the phandle for the interrupt controller that
+  services interrupts for this device.

Don't even mention this one.  It can often be inherited from a parent
node.

deleted.

[...]

quoted

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index a76d85f..6f59fae 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 +638,16 @@ static struct i2c_algorithm i2c_davinci_algo = {
 	.functionality	= i2c_davinci_func,
 };
 
+#if defined(CONFIG_OF)
+static const struct of_device_id davinci_i2c_of_match[] = {
+	{.compatible = "ti,davinci-i2c", },
+	{},
+}
+MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
+#else
+#define davinci_i2c_of_match NULL
+#endif

The #else clause can be dropped if you use the of_match_ptr() macro
when referencing it.

removed.

quoted

+
 static int davinci_i2c_probe(struct platform_device *pdev)
 {
 	struct davinci_i2c_dev *dev;

@@ -676,7 +689,34 @@ 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 device_node *pinmux_np;
+		struct davinci_i2c_platform_data *pdata;
+		u32 prop;
+
+		dev->dev->platform_data = &davinci_i2c_platform_data_default;

Don't do this.  What if a davinci part shows up with two i2c busses?
Use devm_kzalloc() instead.

Fixed.

quoted

+		pdata = &davinci_i2c_platform_data_default;
+		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;
+		if (!of_property_read_u32(pdev->dev.of_node, "id",
+			&prop)) {
+			pdev->id = prop;
+			pdev->dev.init_name = kzalloc(20, GFP_KERNEL);
+			sprintf((char *)pdev->dev.init_name,
+				"i2c_davinci.%d", pdev->id);

Blech!  Drop this.  Leave the core code to set the device name.

completely removed.

quoted

 	dev->clk = clk_get(&pdev->dev, NULL);
+
 	if (IS_ERR(dev->clk)) {

Nit: unrelated whitespace change

Ups, good catch, fixed.

[...]

bye,
Heiko
-- 
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