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<div><font color="#1F497D">Stephen beat me to it. Look at how our other drivers do HW manipulation w/o bitfields and mimic them if you get stuck (SPI, MMC, etc.).</font></div>
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<div><font color="#1F497D">My take is that we’d be better off pushing a Harmony dts file first, since that seems to be the most used/available Tegra2 board out there AFAIK. And getting a dts file reviewed by U-Boot denizens isn’t much help, since fdt/dts is
new to U-Boot upstream. Better to have it looked over by Linux and/or devicetree experts first, as Stephen says.</font></div>
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<div><font color="#1F497D">Tom</font></div>
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<div style="padding-left: 36pt; "><font face="Tahoma, sans-serif" size="2">_____________________________________________<br>
<b>From:</b> Stephen Warren <br>
<b>Sent:</b> Friday, November 18, 2011 9:15 AM<br>
<b>To:</b> Mayuresh Kulkarni; Uboot-dev<br>
<b>Cc:</b> Pritesh Raithatha; Varun Wadekar; devicetree-discuss@lists.ozlabs.org<br>
<b>Subject:</b> RE: Need some advice on LCD driver in Chrome u-boot</font></div>
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<div style="padding-left: 36pt; "><font face="Courier New, monospace" size="2" color="#1F497D">AIUI, yes you’ll need to rewrite the LCD driver, but this should just be a manual replacement of the bit-twiddling macros with manually coded manipulations.</font></div>
<div style="padding-left: 36pt; "><font face="Courier New, monospace" size="2" color="#1F497D"> </font></div>
<div style="padding-left: 36pt; "><font face="Courier New, monospace" size="2" color="#1F497D">I don’t see much point upstreaming a .dts file that’s completely untested; having it upstream before we’re able to use it won’t benefit us in any way, will it? Now,
if we started initializing a bunch of stuff besides LCD from it, then it’d make sense.</font></div>
<div style="padding-left: 36pt; "><font face="Courier New, monospace" size="2" color="#1F497D"> </font></div>
<div style="padding-left: 36pt; "><font face="Courier New, monospace" size="2" color="#1F497D">Please make sure you have the LCD bindings (and whole .dts file) reviewed on <a href="mailto:devicetree-discuss@lists.ozlabs.org"><font color="#0000FF"><u>devicetree-discuss@lists.ozlabs.org</u></font></a>,
since that’s the main .dts review list. The .dts needs to be co-ordinated with other users such as the Linux kernel.</font></div>
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<div style="padding-left: 72pt; "><font face="Tahoma, sans-serif" size="2">_____________________________________________<br>
<b>From:</b> Mayuresh Kulkarni <br>
<b>Sent:</b> Thursday, November 17, 2011 11:27 PM<br>
<b>To:</b> Uboot-dev<br>
<b>Cc:</b> Pritesh Raithatha; Varun Wadekar<br>
<b>Subject:</b> Need some advice on LCD driver in Chrome u-boot</font></div>
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<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">Hi All,</font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2"> </font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">I need advice on following points about up-streaming the LCD driver:</font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2"> </font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">- Chrome’s u-boot implementation uses special bit-fields macros to implement the core display driver (for register read/writes). You can check this implementation in u-boot/arch/arm/cpu/armv7/tegra2/display.c.</font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">- As you might be aware, Pritesh is working on getting I2C driver up-stream which also uses bit-field macros in Chrome’s u-boot. He has been given a comment that, this needs to be removed
before up-streaming, as these macros are not accepted by Denx.</font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">- As I understand, this means that the display driver needs to be rewritten to use standard readl/writel APIs. Is this correct understanding?</font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">- If it needs to be rewritten, it is going to take some time. So is it OK if we push a reviewed copy of tegra2-ventana.dts (name could be decided upon) to Denx’s master branch at this
point of time? This commit will not be tested as there is no driver in master which would use this. Are such commits accepted?</font></div>
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<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2">In general, how are such issues handled by the u-boot community?</font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2"> </font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2"><b>Mayuresh Kulkarni</b></font></div>
<div style="padding-left: 72pt; "><font face="Arial, sans-serif" size="2" color="#92D050">NVIDIA Graphics Pvt Ltd</font></div>
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