lkml.org 
[lkml]   [2017]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH v3 5/5] mtd: spi-nor: cadence-quadspi: Add runtime PM support
From
Date
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

\
 
 \ /
  Last update: 2017-09-27 12:50    [W:0.118 / U:0.308 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site