Re: [PATCH] lis3lv02d: support both one- and two-byte sensors

From: Ãric Piel
Date: Tue Feb 10 2009 - 19:16:24 EST


Giuseppe Bilotta schreef:

As pointed out by Eric, there's no need to jump through hoops to obtain
a signed 16-bit number from a signed 8-bit number.

This patch is good for -mm

Note also that this patch is only about 8 vs 16 bit data, so the axis
orientation for HP notebooks still has to be fixed in a separate patch,
but at least now I should be able to check it out properly.

Whoops, sorry for not catching it before, this part is not nice:

@@ -121,6 +125,21 @@ void lis3lv02d_poweron(acpi_handle handle)
{
adev.is_on = 1;
adev.init(handle);
+ adev.read(handle, WHO_AM_I, &adev.whoami);
+ /* Tell apart LISxLV02Dy from LISx02Dy family by checking the LSB
+ * (0x3A vs 0x3B). TODO More sophisticated checks on other registers
+ * could be implemented, for example to see if we have 2 or 3 axes, and
+ * configure the joystick accordingly.
+ */
+ if (adev.whoami & 1) {
+ printk(KERN_INFO DRIVER_NAME ": 1-byte sensor found\n");
+ adev.lis3lv02d_read = lis3lv02d_read_8;
+ adev.mdps_max_val = 128;
+ } else {
+ printk(KERN_INFO DRIVER_NAME ": 2-byte sensor found\n");
+ adev.lis3lv02d_read = lis3lv02d_read_16;
+ adev.mdps_max_val = 2048;
+ }
}
poweron() is called each time the joystick is opened, no need to check (and do a printk) so often! You need to move all this check to lis3lv02d_add() in hp_accel.c . Moreover, don't do tricky things like (adev.whoami & 1): just do a:
switch (adev.whoami) {
LIS302DL_ID:
printk(KERN_INFO DRIVER_NAME ": 1-byte sensor found.\n");
adev.lis3lv02d_read = lis3lv02d_read_8;
adev.mdps_max_val = 128;
break;
LIS3LV02DL_ID:
printk(KERN_INFO DRIVER_NAME ": 2-byte sensor found.\n");
adev.lis3lv02d_read = lis3lv02d_read_16;
adev.mdps_max_val = 2048;
break;
default:
printk(KERN_ERR DRIVER_NAME ": unknown sensor found of type %d.\n", adev.whoami);
return -EINVAL;
}


Eric
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