Messages in this thread |  | | Date | Thu, 28 Sep 2017 08:01:36 -0700 (PDT) | From | matthew.gerlach@linux ... | Subject | Re: [PATCH v3 5/5] mtd: spi-nor: cadence-quadspi: Add runtime PM support |
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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.
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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