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From: shawn.guo@linaro.org (Shawn Guo)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/1] ARM: imx: Correct the comments in time.c
Date: Thu, 7 May 2015 20:59:03 +0800	[thread overview]
Message-ID: <20150507125858.GH3162@dragon> (raw)
In-Reply-To: <1430343627-60688-1-git-send-email-shenwei.wang@freescale.com>

On Wed, Apr 29, 2015 at 04:40:27PM -0500, Shenwei Wang wrote:
> The comments were corrected as the following to reflect
> the real situation of Freescale MXC timer IP block.
> There are totally 4 version of the timer on Freescale i.MX SoCs.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@freescale.com>
> ---
>  arch/arm/mach-imx/time.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/time.c b/arch/arm/mach-imx/time.c
> index acb1ff5..b1698e1 100644
> --- a/arch/arm/mach-imx/time.c
> +++ b/arch/arm/mach-imx/time.c
> @@ -38,9 +38,11 @@
>  #include "hardware.h"
>  
>  /*
> - * There are 2 versions of the timer hardware on Freescale MXC hardware.
> - * Version 1: MX1/MXL, MX21, MX27.
> - * Version 2: MX25, MX31, MX35, MX37, MX51
> + * There are 4 versions of the timer hardware on Freescale MXC hardware.
> + * Version 0: MX1/MXL
> + * Version 1: MX21, MX27.
> + * Version 2: MX25, MX31, MX35, MX37, MX51, MX6Q(rev1.0)
> + * Version 3: MX6DL, MX6SX, MX6Q(rev1.1+)

This is the problem with version numbers.  Version numbers defined by
software are too arbitrary and could conflict with the ones defined by
IP design (i.e. IPUv3) some day.  Just for example, if some day GPTv2
IP comes with some significant design changes, "v2" will becomes a
source of confusion between software and hardware.  It's even worse if
we already defined fsl,gpt-v2 as the device tree compatible.  That's why
we can only use the version number defined by hardware in device tree
binding.  If no hardware version is given, the best bet would be use SoC
name in the bindings to specify the particular programming model of the
IP block.

I applied patch to drop the version numbers as below.

diff --git a/arch/arm/mach-imx/time.c b/arch/arm/mach-imx/time.c
index acb1ff577cda..ab5ee1c445f3 100644
--- a/arch/arm/mach-imx/time.c
+++ b/arch/arm/mach-imx/time.c
@@ -38,9 +38,11 @@
 #include "hardware.h"
 
 /*
- * There are 2 versions of the timer hardware on Freescale MXC hardware.
- * Version 1: MX1/MXL, MX21, MX27.
- * Version 2: MX25, MX31, MX35, MX37, MX51
+ * There are 4 versions of the timer hardware on Freescale MXC hardware.
+ *  - MX1/MXL
+ *  - MX21, MX27.
+ *  - MX25, MX31, MX35, MX37, MX51, MX6Q(rev1.0)
+ *  - MX6DL, MX6SX, MX6Q(rev1.1+)
  */
 
 /* defines common for all i.MX */

Shawn

  reply	other threads:[~2015-05-07 12:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-29 21:40 [PATCH 1/1] ARM: imx: Correct the comments in time.c Shenwei Wang
2015-05-07 12:59 ` Shawn Guo [this message]
2015-05-07 15:04   ` Shenwei Wang

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