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| author | Boris Brezillon <boris.brezillon@free-electrons.com> | 2015-12-02 15:10:40 +0100 |
|---|---|---|
| committer | Boris Brezillon <boris.brezillon@free-electrons.com> | 2016-04-19 22:05:37 +0200 |
| commit | 2f9992e080b8892a10d189cbc846c06e6594ad0b (patch) | |
| tree | 6c1f9950de031377b53548fde1a413181bc5101f /drivers/mtd | |
| parent | 9edb47004e2afb5884d0c900cbd1ece8b2d6f403 (diff) | |
| download | op-kernel-dev-2f9992e080b8892a10d189cbc846c06e6594ad0b.zip op-kernel-dev-2f9992e080b8892a10d189cbc846c06e6594ad0b.tar.gz | |
mtd: nand: sunxi: fix clk rate calculation
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 <boris.brezillon@free-electrons.com>
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/nand/sunxi_nand.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c index 546a9ca..05b3303 100644 --- a/drivers/mtd/nand/sunxi_nand.c +++ b/drivers/mtd/nand/sunxi_nand.c @@ -1208,12 +1208,12 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip, 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 + * Unlike what is stated in Allwinner datasheet, the clk_rate should + * be set to (1 / min_clk_period), and not (2 / min_clk_period). + * This new formula was verified with a scope and validated by + * Allwinner engineers. */ - chip->clk_rate = (2 * NSEC_PER_SEC) / min_clk_period; + chip->clk_rate = NSEC_PER_SEC / min_clk_period; return 0; } |
