On Fri, Feb 27, 2009 at 01:58:46PM -0800, David Brownell wrote:

On Friday 27 February 2009, Andrew Morton wrote:

quoted

quoted

--- a/drivers/mfd/twl4030-core.c
+++ b/drivers/mfd/twl4030-core.c

@@ -101,6 +101,12 @@

 #define twl_has_usb()        false
 #endif
 
+#if defined(CONFIG_INPUT_TWL4030_PWRBUTTON) \
+     || defined(CONFIG_INPUT_TWL4030_PWBUTTON_MODULE)

OK, this is "wrong".  The core shouldn't need to know about specific
clients.

This is a pretty standard idiom:  only create the device
nodes a system actually uses.  Applied comprehensively,
the kernel footprint shrinks ... supporting a device can
require a lot of ancillary infrastructure, which may not
need to be compiled in.

quoted

quoted

+#define twl_has_pwrbutton()  true
+#else
+#define twl_has_pwrbutton()  false
+#endif
 
 /* Triton Core internal information (BEGIN) */
 

@@ -526,6 +532,13 @@ add_children(struct twl4030_platform_data *pdata, unsigned long features)

              usb_transceiver = child;
      }
 
+     if (twl_has_pwrbutton()) {
+             child = add_child(1, "twl4030_pwrbutton",
+                             NULL, 0, true, pdata->irq_base + 8 + 0, 0);
+             if (IS_ERR(child))
+                     return PTR_ERR(child);
+     }
+
      if (twl_has_regulator()) {
              /*
              child = add_regulator(TWL4030_REG_VPLL1, pdata->vpll1);

The client module should register itself with the core, rather than the core
registering the client.

What has gone wrong here?

Not much I can see.  It's registering a platform_device,
but only if it could be used on this system.  Quite a lot
of OMAP3 boards don't hook up this power button.

Maybe it should also verify that *this* board supports
a power button.  A boolean flag in the twl4030 platform
data would suffice, for multi-board kernels.

something like the following should be enough then:

============== cut here ===================

diff --git a/drivers/mfd/twl4030-core.c b/drivers/mfd/twl4030-core.c
index c86bc3b..714073f 100644
--- a/drivers/mfd/twl4030-core.c
+++ b/drivers/mfd/twl4030-core.c

@@ -532,7 +532,7 @@ add_children(struct twl4030_platform_data *pdata, unsigned long features)
                usb_transceiver = child;
        }
 
-       if (twl_has_pwrbutton()) {
+       if (twl_has_pwrbutton() && pdata->pwrbutton) {
                child = add_child(1, "twl4030_pwrbutton",
                                NULL, 0, true, pdata->irq_base + 8 + 0, 0);
                if (IS_ERR(child))

diff --git a/include/linux/i2c/twl4030.h b/include/linux/i2c/twl4030.h
index 8137f66..277451e 100644
--- a/include/linux/i2c/twl4030.h
+++ b/include/linux/i2c/twl4030.h

@@ -293,6 +293,8 @@ struct twl4030_platform_data {
        struct regulator_init_data              *vaux3;
        struct regulator_init_data              *vaux4;
 
+       bool                                    pwrbutton;
+
        /* REVISIT more to come ... _nothing_ should be hard-wired */
 };
 

-- 
balbi
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