Hi,

On 9/28/2017 8:31 PM, matthew.gerlach@linux.intel.com wrote:

Hi Vignesh,

I tried this patch on an Arria10 SOCFPGA devkit against the 4.1.33-ltsi kernel, and it did not go well. Commands to the flash chip timedout resulting in the probe function failing. I ran into other problems, not related to cadence-quadspi, that prevented me from testing against 4.9 and 4.12 kernels, but I suspect similar behavior.

Ok, thanks! I will keep the clk_*() calls for now.

Regards
Vignesh

Matthew Gerlach

On Wed, 27 Sep 2017, Vignesh R wrote:

Hi Matthew,

On Tuesday 26 September 2017 05:19 AM, Marek Vasut wrote:
[...]

Ok thanks! Do you know if pm_runtime_get_sync() can enable clocks for >>>>>> QSPI on SoCFPGA or if clk_prepare_enable() is needed? Just trying to see >>>>>> if its possible to get rid of clk_*() calls in favor of pm_*() calls. >>>>>

Not of the top of my head, sorry. +CC Matthew, he should know.

I am not an expert at the clock framework nor the power management, but I >>>> did ask around a bit.  No one I asked was planning to change the clk_*() >>>> calls to pm_*() call, but the feedback was that it would be a good idea. >>>

The question is, if we do the replacement, will it break on socfpga ?
A quick test might be useful.

yes, a quick qspi test with clk_prepare_enable() replaced by pm_*() calls
like below patch would be helpful:


diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 53c7d8e0327a..7ad3e176cc88 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -34,6 +34,7 @@
#include <linux/sched.h>
#include <linux/spi/spi.h>
#include <linux/timer.h>
+#include <linux/pm_runtime.h>

#define CQSPI_NAME "cadence-qspi"
#define CQSPI_MAX_CHIPSELECT 16
@@ -1206,11 +1207,8 @@ static int cqspi_probe(struct platform_device *pdev) >> return -ENXIO;
}

- ret = clk_prepare_enable(cqspi->clk);
- if (ret) {
- dev_err(dev, "Cannot enable QSPI clock.\n");
- return ret;
- }
+ pm_runtime_enable(dev);
+ pm_runtime_get_sync(dev);

cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);





--
Regards
Vignesh

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