Thread (20 messages) flat view 20 messages, 2 authors, 2016-04-13

[PATCH 02/16] mtd: nand: sunxi: fix clk rate calculation

From: Thomas Petazzoni <hidden>
Date: 2016-03-08 14:58:19
Also in: lkml

Boris,

On Mon,  7 Mar 2016 17:18:19 +0100, Boris Brezillon wrote:
quoted hunk ↗ jump to hunk
Unlike what is specified in the Allwinner datasheets, the NAND clock rate
is not equal to 2/T but 1/T. Fix the clock rate selection accordingly.

Signed-off-by: Boris Brezillon <redacted>
---
 drivers/mtd/nand/sunxi_nand.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
index 4d01e65..ab66d8d 100644
--- a/drivers/mtd/nand/sunxi_nand.c
+++ b/drivers/mtd/nand/sunxi_nand.c
@@ -1208,13 +1208,7 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip,
 	/* Convert min_clk_period from picoseconds to nanoseconds */
 	min_clk_period = DIV_ROUND_UP(min_clk_period, 1000);
 
-	/*
-	 * Convert min_clk_period into a clk frequency, then get the
-	 * appropriate rate for the NAND controller IP given this formula
-	 * (specified in the datasheet):
-	 * nand clk_rate = 2 * min_clk_rate
-	 */
When some HW works in a way that is *NOT* the one specified in the
datasheet, I think you should rather add *more* comments about this
aspect, rather than removing existing comments.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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