[PATCH 03/10] spi: rzv2m-csi: Rework CSI_CKS_MAX definition

[Fabrizio Castro]

Clock "csiclk" gets divided by 2 * CSI_CLKSEL_CKS in order to generate
the serial clock (output from master), with CSI_CLKSEL_CKS ranging from
0x1 (that means "csiclk" is divided by 2) to 0x3FFF ("csiclk" is divided
by 32766). CSI_CKS_MAX is used for referring to the setting
corresponding to the maximum frequency divider.
Value 0x3FFF for CSI_CKS_MAX doesn't really means much to the reader
without an explanation and a more readable definition.

Add a comment with a meaningful description and also replace value
0x3FFF with the corresponding GENMASK, to make it very clear what the
macro means.

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@xxxxxxxxxxx>
---
 drivers/spi/spi-rzv2m-csi.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-rzv2m-csi.c b/drivers/spi/spi-rzv2m-csi.c
index 3931045a85eb..621774949bde 100644
--- a/drivers/spi/spi-rzv2m-csi.c
+++ b/drivers/spi/spi-rzv2m-csi.c
@@ -65,7 +65,12 @@
 #define CSI_FIFO_SIZE_BYTES	32
 #define CSI_FIFO_HALF_SIZE	16
 #define CSI_EN_DIS_TIMEOUT_US	100
-#define CSI_CKS_MAX		0x3FFF
+/*
+ * Clock "csiclk" gets divided by 2 * CSI_CLKSEL_CKS in order to generate the
+ * serial clock (output from master), with CSI_CLKSEL_CKS ranging from 0x1 (that
+ * means "csiclk" is divided by 2) to 0x3FFF ("csiclk" is divided by 32766).
+ */
+#define CSI_CKS_MAX		GENMASK(13, 0)
 
 #define UNDERRUN_ERROR		BIT(0)
 #define OVERFLOW_ERROR		BIT(1)
-- 
2.34.1