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From: Stephen Warren <swarren@wwwdotorg.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] fdt: __of_translate_address(): check parent's 'ranges' before translate
Date: Thu, 7 Jan 2016 11:25:15 -0700	[thread overview]
Message-ID: <568EAD8B.6090909@wwwdotorg.org> (raw)
In-Reply-To: <1452166849-24461-1-git-send-email-p.marczak@samsung.com>

On 01/07/2016 04:40 AM, Przemyslaw Marczak wrote:
> The present implementation of __of_translate_address() taken
> from the Linux, is designed for translate bus/child address
> mappings by using 'ranges' property - and it doesn't allow
> for checking an address for a device's node with zero size-cells.
>
> The 'size-cells > 0' is required for bus/child address mapping,
> but is not required for non-memory mapped address, e.g.: I2C chip.
> Then when we need only raw 'reg' property's value.
>
> Since the I2C device address goes to a single-cell reg property,
> support for that case is welcome, but currently calling dev_get_addr()
> for I2C device will return 'FDT_ADDR_T_NONE', and print the warning:
>
> warning:
> __of_translate_address: Bad cell count for 'some-dev'

This patch takes the wrong approach.

It simply doesn't make sense to /attempt/ to translate an I2C address 
into an MMIO address space. It's a nonsensical operation; no such 
translation is possible under any circumstances because I2C and MMIO 
addresses mean completely different things and simply can't be 
translated to each-other.

Rather than making this nonsensical operation succeed in a way that 
gives the desired no-op result, the nonsensical operation simply 
shouldn't be performed in the first place.

  parent reply	other threads:[~2016-01-07 18:25 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-07 11:40 [U-Boot] [PATCH] fdt: __of_translate_address(): check parent's 'ranges' before translate Przemyslaw Marczak
2016-01-07 13:03 ` Lukasz Majewski
2016-01-07 18:25 ` Stephen Warren [this message]
2016-01-11 11:21   ` Przemyslaw Marczak
2016-01-11 16:47     ` Stephen Warren
2016-01-12 10:25       ` Przemyslaw Marczak
2016-01-12 13:57         ` Simon Glass
2016-01-12 14:22           ` Przemyslaw Marczak
2016-01-12 15:13             ` Simon Glass
2016-01-12 16:43         ` Stephen Warren
2016-01-13 11:10           ` Przemyslaw Marczak
2016-01-14 17:17             ` Simon Glass
2016-01-15 10:41               ` Przemyslaw Marczak
2016-01-15 16:35                 ` Stephen Warren
2016-01-29 18:23                   ` Simon Glass
2016-02-02  8:55                     ` Przemyslaw Marczak

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