[PATCH v2 3/3] mtd: nand: lpc32xx_slc: fix calculation of timing arcs from given values

[Vladimir Zapolskiy]

According to LPC32xx User's Manual all values measured in clock cycles
are programmable from 1 to 16 clocks (4 bits) starting from 0 in
bitfield, the current version of calculated clock cycles is too
conservative.

Correctness of 0 bitfield value (i.e. programmed 1 clock
timing) is proven with actual NAND chip devices.

Signed-off-by: Vladimir Zapolskiy <vz at mleia.com>
---
Changes from v2 to v1:
* use less conservative "DIV_ROUND_UP(c, n) - 1" construction instead of "c / n"

 drivers/mtd/nand/lpc32xx_slc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/lpc32xx_slc.c b/drivers/mtd/nand/lpc32xx_slc.c
index a9e8a02..cbf4501 100644
--- a/drivers/mtd/nand/lpc32xx_slc.c
+++ b/drivers/mtd/nand/lpc32xx_slc.c
@@ -95,7 +95,7 @@
 * slc_tac register definitions
 **********************************************************************/
 /* Computation of clock cycles on basis of controller and device clock rates */
-#define SLCTAC_CLOCKS(c, n, s)	(min_t(u32, 1 + (c / n), 0xF) << s)
+#define SLCTAC_CLOCKS(c, n, s)	(min_t(u32, DIV_ROUND_UP(c, n) - 1, 0xF) << s)
 
 /* Clock setting for RDY write sample wait time in 2*n clocks */
 #define SLCTAC_WDR(n)		(((n) & 0xF) << 28)
-- 
2.1.4