Re: [v2, 1/4] ARM: davinci: da8xx-dt: Add ti-aemif lookup for clock matching

From: David Lechner
Date: Fri Dec 30 2016 - 19:52:58 EST

On 08/10/2016 06:00 AM, Karl Beldan wrote:
Many davinci boards (da830 and da850 families) don't have their clocks
in DT yet and won't be successful in getting an unnamed aemif clock
without explicitly registering them via clk_lookups, failing the
ti-aemif memory driver probe.

The current aemif lookup entry resolving to the same clock:
'CLK(NULL, "aemif", &aemif_clk)'
remains, as it is currently used (davinci_nand is getting a named clock

This change will allow to switch from the mach-davinci aemif code to
the ti-aemif memory driver.

Signed-off-by: Karl Beldan <kbeldan@xxxxxxxxxxxx>

FYI, I can't boot LEGO MINDSTORMS EV3 (AM1908) with a v4.9 mainline kernel. I did a git bisect and traced it down to this patch. I'm guessing that simply reverting it will break other things.

The problem is that &aemif_clk is a node in a linked list and points to itself, which creates an infinite loop when looking up the usb clocks that are later in the list.

I thought there was a patch to fix this properly from one of the Bay Libre guys to fix this already, but I can't seem to find it at the moment. When it is found, it would be good to have it applied to the 4.9 stable and 4.10 mainline trees.

arch/arm/mach-davinci/da850.c | 1 +
arch/arm/mach-davinci/da8xx-dt.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/arm/mach-davinci/da850.c b/arch/arm/mach-davinci/da850.c
index 2398862..3477d30 100644
--- a/arch/arm/mach-davinci/da850.c
+++ b/arch/arm/mach-davinci/da850.c
@@ -485,6 +485,7 @@ static struct clk_lookup da850_clks[] = {
CLK("da8xx_lcdc.0", "fck", &lcdc_clk),
CLK("da830-mmc.0", NULL, &mmcsd0_clk),
CLK("da830-mmc.1", NULL, &mmcsd1_clk),
+ CLK("ti-aemif", NULL, &aemif_clk),
CLK(NULL, "aemif", &aemif_clk),
CLK(NULL, "usb11", &usb11_clk),
CLK(NULL, "usb20", &usb20_clk),
diff --git a/arch/arm/mach-davinci/da8xx-dt.c b/arch/arm/mach-davinci/da8xx-dt.c
index ca99711..c9f7e92 100644
--- a/arch/arm/mach-davinci/da8xx-dt.c
+++ b/arch/arm/mach-davinci/da8xx-dt.c
@@ -37,6 +37,7 @@ static struct of_dev_auxdata da850_auxdata_lookup[] __initdata = {
OF_DEV_AUXDATA("ti,davinci-dm6467-emac", 0x01e20000, "davinci_emac.1",
OF_DEV_AUXDATA("ti,da830-mcasp-audio", 0x01d00000, "davinci-mcasp.0", NULL),
+ OF_DEV_AUXDATA("ti,da850-aemif", 0x68000000, "ti-aemif", NULL),