On Fri, Dec 06, 2013 at 12:35:10PM +0400, Alexander Shiyan wrote:
quoted
On Fri, Dec 06, 2013 at 12:03:54PM +0400, Alexander Shiyan wrote:
...
quoted
quoted
quoted
quoted
- fsl,dmacr: DMA Control Register value. This is optional. By default, the
register is not modified as recommended by the datasheet.
+- fsl,pwmr: LCDC PWM Contrast Control Register value. That property is
+ optional, but defining it is necessary to get the backlight working. If that
+ property is ommited, the register is zeroed.
Why isn't this implemented as a backlight driver? Static devicetree
provided values is very limiting.
Let's understand the terminology.
This register should be renamed according to the datasheet, i.e. LPCCR.
As I pointed out earlier, it is NOT control the backlight, this is a contrast control.
Yes, it works as PWM, but nothing do with the backlight subsystem.
Yes, we can make a driver for this PWM, but how are we going to control it?
I misunderstood something?
I stumbled upon 'get the backlight working' which implied for me that it
should be a backlight driver. But you're right and now I remember we
talked about this already.
Hallelujah.
quoted
I still think this should be something adjustable, not static data.
Maybe we could change the wording to something like "This property
provides the default value for the contrast control register" since even
if we add driver support for controlling the contrast we still want
to have a sane default.
Sounds good.
quoted
BTW the contrast could be controlled with a lcd_device (see
lcd_device_register) which seems to be very easy to implement.
Address of register is placed within LCD area, so we cannot use this
memory region, I think is no so easy as you say....
We do not need a separate driver for this. Look for example at
drivers/video/bf537-lq035.c, it just calls lcd_device_register()
in its probe function.
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
PiA+ID4gT24gRnJpLCBEZWMgMDYsIDIwMTMgYXQgMTI6MDM6NTRQTSArMDQwMCwgQWxleGFuZGVy
IFNoaXlhbiB3cm90ZToKPiA+IC4uLgo+ID4gPiA+ID4gPiAgLSBmc2wsZG1hY3I6IERNQSBDb250
cm9sIFJlZ2lzdGVyIHZhbHVlLiBUaGlzIGlzIG9wdGlvbmFsLiBCeSBkZWZhdWx0LCB0aGUKPiA+
ID4gPiA+ID4gIAlyZWdpc3RlciBpcyBub3QgbW9kaWZpZWQgYXMgcmVjb21tZW5kZWQgYnkgdGhl
IGRhdGFzaGVldC4KPiA+ID4gPiA+ID4gKy0gZnNsLHB3bXI6ICBMQ0RDIFBXTSBDb250cmFzdCBD
b250cm9sIFJlZ2lzdGVyIHZhbHVlLiBUaGF0IHByb3BlcnR5IGlzCj4gPiA+ID4gPiA+ICsJb3B0
aW9uYWwsIGJ1dCBkZWZpbmluZyBpdCBpcyBuZWNlc3NhcnkgdG8gZ2V0IHRoZSBiYWNrbGlnaHQg
d29ya2luZy4gSWYgdGhhdAo+ID4gPiA+ID4gPiArCXByb3BlcnR5IGlzIG9tbWl0ZWQsIHRoZSBy
ZWdpc3RlciBpcyB6ZXJvZWQuCj4gPiA+ID4gPiAKPiA+ID4gPiA+IFdoeSBpc24ndCB0aGlzIGlt
cGxlbWVudGVkIGFzIGEgYmFja2xpZ2h0IGRyaXZlcj8gU3RhdGljIGRldmljZXRyZWUKPiA+ID4g
PiA+IHByb3ZpZGVkIHZhbHVlcyBpcyB2ZXJ5IGxpbWl0aW5nLgo+ID4gPiA+IAo+ID4gPiA+IExl
dCdzIHVuZGVyc3RhbmQgdGhlIHRlcm1pbm9sb2d5Lgo+ID4gPiA+IFRoaXMgcmVnaXN0ZXIgc2hv
dWxkIGJlIHJlbmFtZWQgYWNjb3JkaW5nIHRvIHRoZSBkYXRhc2hlZXQsIGkuZS4gTFBDQ1IuCj4g
PiA+ID4gQXMgSSBwb2ludGVkIG91dCBlYXJsaWVyLCBpdCBpcyBOT1QgY29udHJvbCB0aGUgYmFj
a2xpZ2h0LCB0aGlzIGlzIGEgY29udHJhc3QgY29udHJvbC4KPiA+ID4gPiBZZXMsIGl0IHdvcmtz
IGFzIFBXTSwgYnV0IG5vdGhpbmcgZG8gd2l0aCB0aGUgYmFja2xpZ2h0IHN1YnN5c3RlbS4KPiA+
ID4gPiBZZXMsIHdlIGNhbiBtYWtlIGEgZHJpdmVyIGZvciB0aGlzIFBXTSwgYnV0IGhvdyBhcmUg
d2UgZ29pbmcgdG8gY29udHJvbCBpdD8KPiA+ID4gPiBJIG1pc3VuZGVyc3Rvb2Qgc29tZXRoaW5n
Pwo+ID4gPiAKPiA+ID4gSSBzdHVtYmxlZCB1cG9uICdnZXQgdGhlIGJhY2tsaWdodCB3b3JraW5n
JyB3aGljaCBpbXBsaWVkIGZvciBtZSB0aGF0IGl0Cj4gPiA+IHNob3VsZCBiZSBhIGJhY2tsaWdo
dCBkcml2ZXIuIEJ1dCB5b3UncmUgcmlnaHQgYW5kIG5vdyBJIHJlbWVtYmVyIHdlCj4gPiA+IHRh
bGtlZCBhYm91dCB0aGlzIGFscmVhZHkuCj4gPiAKPiA+IEhhbGxlbHVqYWguCj4gPiAKPiA+ID4g
SSBzdGlsbCB0aGluayB0aGlzIHNob3VsZCBiZSBzb21ldGhpbmcgYWRqdXN0YWJsZSwgbm90IHN0
YXRpYyBkYXRhLgo+ID4gPiBNYXliZSB3ZSBjb3VsZCBjaGFuZ2UgdGhlIHdvcmRpbmcgdG8gc29t
ZXRoaW5nIGxpa2UgIlRoaXMgcHJvcGVydHkKPiA+ID4gcHJvdmlkZXMgdGhlIGRlZmF1bHQgdmFs
dWUgZm9yIHRoZSBjb250cmFzdCBjb250cm9sIHJlZ2lzdGVyIiBzaW5jZSBldmVuCj4gPiA+IGlm
IHdlIGFkZCBkcml2ZXIgc3VwcG9ydCBmb3IgY29udHJvbGxpbmcgdGhlIGNvbnRyYXN0IHdlIHN0
aWxsIHdhbnQKPiA+ID4gdG8gaGF2ZSBhIHNhbmUgZGVmYXVsdC4KPiA+IAo+ID4gU291bmRzIGdv
b2QuCj4gPiAKPiA+ID4gQlRXIHRoZSBjb250cmFzdCBjb3VsZCBiZSBjb250cm9sbGVkIHdpdGgg
YSBsY2RfZGV2aWNlIChzZWUKPiA+ID4gbGNkX2RldmljZV9yZWdpc3Rlcikgd2hpY2ggc2VlbXMg
dG8gYmUgdmVyeSBlYXN5IHRvIGltcGxlbWVudC4KPiA+IAo+ID4gQWRkcmVzcyBvZiByZWdpc3Rl
ciBpcyBwbGFjZWQgd2l0aGluIExDRCBhcmVhLCBzbyB3ZSBjYW5ub3QgdXNlIHRoaXMKPiA+IG1l
bW9yeSByZWdpb24sIEkgdGhpbmsgaXMgbm8gc28gZWFzeSBhcyB5b3Ugc2F5Li4uLgo+IAo+IFdl
IGRvIG5vdCBuZWVkIGEgc2VwYXJhdGUgZHJpdmVyIGZvciB0aGlzLiBMb29rIGZvciBleGFtcGxl
IGF0Cj4gZHJpdmVycy92aWRlby9iZjUzNy1scTAzNS5jLCBpdCBqdXN0IGNhbGxzIGxjZF9kZXZp
Y2VfcmVnaXN0ZXIoKQo+IGluIGl0cyBwcm9iZSBmdW5jdGlvbi4KCk5pY2UuIFNlZW1zIHRoaXMg
ZXhhbXBsZSBldmVuIGNhbiBoYW5kbGUgTENEIHBvd2VyCnJlZ3VsYXRvciBmcm9tICJbMS80XSB2
aWRlbzogaW14ZmI6IEludHJvZHVjZSByZWd1bGF0b3Igc3VwcG9ydC4iCgotLS0K