Messages in this thread |  | | From | <> | Subject | Re: [PATCHv2] mtd: spi-nor: cadence-quadspi: add reset control | Date | Wed, 17 Apr 2019 08:48:45 +0000 |
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Hi, Dinh,
On 04/09/2019 06:38 PM, Dinh Nguyen wrote: > Get the reset control for the QSPI controller and bring it out of reset.
Is there a public datasheet where I can check this? > > Suggested-by: Tien-Fong Chee <tien.fong.chee@intel.com> > Signed-off-by: Dinh Nguyen <dinguyen@kernel.org> > --- > v2: use devm_reset_control_get_optional_exclusive > print an error message > return -EPROBE_DEFER > --- > drivers/mtd/spi-nor/cadence-quadspi.c | 14 ++++++++++++++
would you update the bindings as well?
> 1 file changed, 14 insertions(+) > > diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c > index 792628750eec..c548567adcf0 100644 > --- a/drivers/mtd/spi-nor/cadence-quadspi.c > +++ b/drivers/mtd/spi-nor/cadence-quadspi.c > @@ -34,6 +34,7 @@ > #include <linux/of.h> > #include <linux/platform_device.h> > #include <linux/pm_runtime.h> > +#include <linux/reset.h> > #include <linux/sched.h> > #include <linux/spi/spi.h> > #include <linux/timer.h> > @@ -1336,6 +1337,7 @@ static int cqspi_probe(struct platform_device *pdev) > struct cqspi_st *cqspi; > struct resource *res; > struct resource *res_ahb; > + struct reset_control *rstc; > const struct cqspi_driver_platdata *ddata; > int ret; > int irq; > @@ -1362,6 +1364,18 @@ static int cqspi_probe(struct platform_device *pdev) > return PTR_ERR(cqspi->clk); > } > > + /* Obtain QSPI reset control */
OSPI version of the IP has been added recently. Is this available just for QSPI?
> + rstc = devm_reset_control_get_optional_exclusive(dev, NULL); > + if (IS_ERR(rstc)) { > + dev_err(dev, "Cannot get QSPI reset.\n"); > + if (PTR_ERR(rstc) == -EPROBE_DEFER) > + return -EPROBE_DEFER;
why ignoring all the other possible errors? Maybe return PTR_ERR(rstc); ?
> + } else { > + reset_control_assert(rstc);
Shouldn't the clock be enabled before asserting reset?
Does it matter if reset_control_assert() is returning any error?
> + udelay(1);
Is there a range or 1 us is the maximum time that we should wait?
> + reset_control_deassert(rstc);
Should we check if reset_control_deassert() is returning any error?
Cheers, ta
> + } > + > /* Obtain and remap controller address. */ > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > cqspi->iobase = devm_ioremap_resource(dev, res); >
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