[PATCH v3 1/3] ARM: da850: fix infinite loop in clk_set_rate()

On Tuesday 06 December 2016 05:28 PM, Bartosz Golaszewski wrote:

2016-12-05 11:15 GMT+01:00 Sekhar Nori [off-list ref]:

quoted

On Monday 05 December 2016 03:39 PM, Bartosz Golaszewski wrote:

quoted

The aemif clock is added twice to the lookup table in da850.c. This
breaks the children list of pll0_sysclk3 as we're using the same list
links in struct clk. When calling clk_set_rate(), we get stuck in
propagate_rate().

Create a separate clock for nand, inheriting the rate of the aemif
clock and retrieve it in the davinci_nand module.

Signed-off-by: Bartosz Golaszewski <redacted>
---
 arch/arm/mach-davinci/da850.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-davinci/da850.c b/arch/arm/mach-davinci/da850.c
index e770c97..c008e5e 100644
--- a/arch/arm/mach-davinci/da850.c
+++ b/arch/arm/mach-davinci/da850.c

@@ -367,6 +367,11 @@ static struct clk aemif_clk = {
      .flags          = ALWAYS_ENABLED,
 };

+static struct clk aemif_nand_clk = {
+     .name           = "nand",
+     .parent         = &aemif_clk,
+};
+
 static struct clk usb11_clk = {
      .name           = "usb11",
      .parent         = &pll0_sysclk4,

@@ -537,7 +542,7 @@ static struct clk_lookup da850_clks[] = {
      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,               "aemif",        &aemif_nand_clk),

Why use a NULL device name here?

Hi Sekhar,

there's an issue with this bit. I added an of_dev_auxdata entry to
da8xx-dt.c for the nand node, but it didn't work (the nand driver
could not get the clock). When I dug deeper, it turned out, the nand
node is created from aemif_probe() instead of from
da850_init_machine() and the lookup table is not passed as argument to
of_platform_populate().

There are two solutions: one is using "620000000.nand" as dev_id in
the clock lookup table, but that's ugly. The second is leaving dev_id
as NULL - I verified that the nand driver works correctly having only
the connector id. Please let me know which one you prefer or if you
have other ideas.

Alright, I will take a look at whats going on here. This series will
have to wait for v4.11 anyway.

Thanks,
Sekhar