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@xxxxxx>
---
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);
+ 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);
--
2.30.0
