From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 02/16] mtd: nand: sunxi: fix clk rate calculation
Date: Tue, 8 Mar 2016 15:58:03 +0100 [thread overview]
Message-ID: <20160308155803.1b0263eb@free-electrons.com> (raw)
In-Reply-To: <1457367513-26069-3-git-send-email-boris.brezillon@free-electrons.com>
Boris,
On Mon, 7 Mar 2016 17:18:19 +0100, Boris Brezillon wrote:
> 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>
> ---
> 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
next prev parent reply other threads:[~2016-03-08 14:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-07 16:18 [PATCH 00/16] mtd: nand: sunxi: various improvements/fixes Boris Brezillon
2016-03-07 16:18 ` [PATCH 01/16] mtd: nand: sunxi: fix call order in sunxi_nand_chip_init() Boris Brezillon
2016-03-07 16:18 ` [PATCH 02/16] mtd: nand: sunxi: fix clk rate calculation Boris Brezillon
2016-03-08 14:58 ` Thomas Petazzoni [this message]
2016-03-08 15:20 ` Boris Brezillon
2016-03-07 16:18 ` [PATCH 03/16] mtd: nand: sunxi: fix EDO mode selection Boris Brezillon
2016-03-07 16:18 ` [PATCH 04/16] mtd: nand: sunxi: adapt clk_rate to tWB, tADL, tWHR and tRHW timings Boris Brezillon
2016-03-07 16:18 ` [PATCH 05/16] mtd: nand: export default read/write oob functions Boris Brezillon
2016-03-07 16:18 ` [PATCH 06/16] mtd: nand: sunxi: implement ->read_oob()/->write_oob() Boris Brezillon
2016-03-07 16:18 ` [PATCH 07/16] mtd: nand: sunxi: implement ->read_subpage() Boris Brezillon
2016-03-07 16:20 ` [PATCH 08/16] mtd: nand: sunxi: improve ->cmd_ctrl() function Boris Brezillon
2016-03-07 16:20 ` [PATCH 09/16] mtd: nand: sunxi: let the NAND controller control the CE line Boris Brezillon
2016-03-07 16:21 ` [PATCH 10/16] mtd: nand: sunxi: fix the NFC_ECC_ERR_CNT() macro Boris Brezillon
2016-03-07 16:21 ` [PATCH 11/16] mtd: nand: sunxi: fix NFC_CTL setting Boris Brezillon
2016-03-07 16:21 ` [PATCH 12/16] mtd: nand: sunxi: disable clks on device removal Boris Brezillon
2016-03-07 16:21 ` [PATCH 13/16] mtd: nand: enable ECC pipelining Boris Brezillon
2016-03-07 16:21 ` [PATCH 14/16] mtd: nand: sunxi: fix ->dev_ready() implementation Boris Brezillon
2016-03-07 16:21 ` [PATCH 15/16] mtd: nand: sunxi: make use of readl_poll_timeout() Boris Brezillon
2016-03-07 16:21 ` [PATCH 16/16] mtd: nand: sunxi: poll for events instead of using interrupts Boris Brezillon
2016-04-13 15:27 ` [PATCH 00/16] mtd: nand: sunxi: various improvements/fixes Boris Brezillon
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