Messages in this thread | | | Date | Wed, 24 Mar 2021 00:07:46 +0100 | From | Michael Walle <> | Subject | Re: [RFC PATCH 1/6] spi: spi-mem: Tell controller when device is ready for calibration |
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Hi Pratyush,
Am 2021-03-11 20:12, schrieb Pratyush Yadav: > Some controllers like the Cadence OSPI controller need to perform a > calibration sequence to operate at high clock speeds. This calibration > should happen after the flash is fully initialized otherwise the > calibration might happen in a different SPI mode from the one the flash > is finally set to. Add a hook that can be used to tell the controller > when the flash is ready for calibration. Whether calibration is needed > depends on the controller. > > Signed-off-by: Pratyush Yadav <p.yadav@ti.com> > --- > drivers/spi/spi-mem.c | 12 ++++++++++++ > include/linux/spi/spi-mem.h | 8 ++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c > index dc713b0c3c4d..e2f05ad3f4dc 100644 > --- a/drivers/spi/spi-mem.c > +++ b/drivers/spi/spi-mem.c > @@ -464,6 +464,18 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, > struct spi_mem_op *op) > } > EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size); > > +int spi_mem_do_calibration(struct spi_mem *mem, struct spi_mem_op *op) > +{ > + struct spi_controller *ctlr = mem->spi->controller; > + > + if (!ctlr->mem_ops || !ctlr->mem_ops->do_calibration) > + return -EOPNOTSUPP; > + > + ctlr->mem_ops->do_calibration(mem, op);
Can't a calibration fail?
> + return 0; > +} > +EXPORT_SYMBOL_GPL(spi_mem_do_calibration); > + > static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc > *desc, > u64 offs, size_t len, void *buf) > { > diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h > index 2b65c9edc34e..97a2d280f2d0 100644 > --- a/include/linux/spi/spi-mem.h > +++ b/include/linux/spi/spi-mem.h > @@ -250,6 +250,12 @@ static inline void *spi_mem_get_drvdata(struct > spi_mem *mem) > * the currently mapped area), and the caller of > * spi_mem_dirmap_write() is responsible for calling it again in > * this case. > + * @do_calibration: perform calibration needed for high SPI clock > speed > + * operation. Should be called after the SPI memory device has > + * been completely initialized. The op passed should contain > + * a template for the read operation used for the device so > + * the controller can decide what type of calibration is > + * required for this type of read. > * > * This interface should be implemented by SPI controllers providing > an > * high-level interface to execute SPI memory operation, which is > usually the > @@ -274,6 +280,7 @@ struct spi_controller_mem_ops { > u64 offs, size_t len, void *buf); > ssize_t (*dirmap_write)(struct spi_mem_dirmap_desc *desc, > u64 offs, size_t len, const void *buf); > + void (*do_calibration)(struct spi_mem *mem, struct spi_mem_op *op); > }; > > /** > @@ -346,6 +353,7 @@ bool spi_mem_dtr_supports_op(struct spi_mem *mem, > #endif /* CONFIG_SPI_MEM */ > > int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op > *op); > +int spi_mem_do_calibration(struct spi_mem *mem, struct spi_mem_op > *op); > > bool spi_mem_supports_op(struct spi_mem *mem, > const struct spi_mem_op *op);
-- -michael
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