Re: [PATCH] i2c i.MX: Fix divider table

From: Richard Zhao <linuxzsc-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
	Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
	Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH] i2c i.MX: Fix divider table
Date: Thu, 5 Jul 2012 22:52:39 +0800	[thread overview]
Message-ID: <20120705145236.GA2735@richard-laptop> (raw)
In-Reply-To: <1341493826-13861-1-git-send-email-s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

On Thu, Jul 05, 2012 at 03:10:26PM +0200, Sascha Hauer wrote:
> Measurements on i.MX1 and i.MX53 have shown that the divider values
> in the datasheets are wrong. the values from first, third and fourth
> column were all measured to be 8 higher than in the datasheet. It
> should be safe to assume that the SoCs between i.MX1 and i.MX53 behave
> the same as the i2c unit is unchanged since the i.MX1.
We may need to check with IC guys? Or you've done?

Thanks
Richard
> 
> Signed-off-by: Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  drivers/i2c/busses/i2c-imx.c |   31 ++++++++++++++++++-------------
>  1 file changed, 18 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 8d6b504..aabbe31 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -98,22 +98,27 @@
>   * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
>   *
>   * Duplicated divider values removed from list
> + *
> + * These values (mostly) do not match the ones in the datasheet because
> + * measurements have shown that the values are wrong. This was tested
> + * on i.MX1 and i.MX53, so it shoud be safe to assume that the SoCs in
> + * between behave the same.
>   */
>  
>  static u16 __initdata i2c_clk_div[50][2] = {
> -	{ 22,	0x20 }, { 24,	0x21 }, { 26,	0x22 }, { 28,	0x23 },
> -	{ 30,	0x00 },	{ 32,	0x24 }, { 36,	0x25 }, { 40,	0x26 },
> -	{ 42,	0x03 }, { 44,	0x27 },	{ 48,	0x28 }, { 52,	0x05 },
> -	{ 56,	0x29 }, { 60,	0x06 }, { 64,	0x2A },	{ 72,	0x2B },
> -	{ 80,	0x2C }, { 88,	0x09 }, { 96,	0x2D }, { 104,	0x0A },
> -	{ 112,	0x2E }, { 128,	0x2F }, { 144,	0x0C }, { 160,	0x30 },
> -	{ 192,	0x31 },	{ 224,	0x32 }, { 240,	0x0F }, { 256,	0x33 },
> -	{ 288,	0x10 }, { 320,	0x34 },	{ 384,	0x35 }, { 448,	0x36 },
> -	{ 480,	0x13 }, { 512,	0x37 }, { 576,	0x14 },	{ 640,	0x38 },
> -	{ 768,	0x39 }, { 896,	0x3A }, { 960,	0x17 }, { 1024,	0x3B },
> -	{ 1152,	0x18 }, { 1280,	0x3C }, { 1536,	0x3D }, { 1792,	0x3E },
> -	{ 1920,	0x1B },	{ 2048,	0x3F }, { 2304,	0x1C }, { 2560,	0x1D },
> -	{ 3072,	0x1E }, { 3840,	0x1F }
> +	{ 30,	0x20 }, { 32,	0x21 }, { 34,	0x22 },	{ 36,	0x23 },
> +	{ 38,	0x00 },	{ 40,	0x24 },	{ 44,	0x25 },	{ 48,	0x26 },
> +	{ 50,	0x03 },	{ 52,	0x27 },	{ 56,	0x28 }, { 60,	0x05 },
> +	{ 64,	0x29 }, { 68,	0x06 }, { 72,	0x2A },	{ 80,	0x2B },
> +	{ 88,	0x2C }, { 96,	0x09 }, { 104,	0x2D }, { 112,	0x0A },
> +	{ 120,	0x2E }, { 136,	0x2F }, { 152,	0x0C },	{ 168,	0x30 },
> +	{ 200,	0x31 }, { 232,	0x32 }, { 248,	0x0F },	{ 264,	0x33 },
> +	{ 288,	0x10 },	{ 328,	0x34 },	{ 392,	0x35 },	{ 456,	0x36 },
> +	{ 480,	0x13 },	{ 520,	0x37 },	{ 576,	0x14 },	{ 648,	0x38 },
> +	{ 776,	0x39 },	{ 904,	0x3A },	{ 960,	0x17 },	{ 1032,	0x3B },
> +	{ 1152,	0x18 },	{ 1288,	0x3C },	{ 1544,	0x3D },	{ 1800,	0x3E },
> +	{ 1920,	0x1B },	{ 2048,	0x3F },	{ 2304,	0x1C },	{ 2560,	0x1D },
> +	{ 3072,	0x1E },	{ 3840,	0x1F }
>  };
>  
>  struct imx_i2c_struct {
> -- 
> 1.7.10
> 
> 
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