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From: Mark Brown <broonie@kernel.org>
To: Stephen Boyd <sboyd@codeaurora.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>,
	Lee Jones <lee.jones@linaro.org>,
	Srinivas Ramana <sramana@codeaurora.org>,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/8] regmap: Add support for using regmap over ssbi
Date: Wed, 11 Dec 2013 00:51:06 +0000	[thread overview]
Message-ID: <20131211005106.GL11468@sirena.org.uk> (raw)
In-Reply-To: <52A7AE1B.3040201@codeaurora.org>

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On Tue, Dec 10, 2013 at 04:13:15PM -0800, Stephen Boyd wrote:
> On 12/10/13 15:50, Mark Brown wrote:
> > On Tue, Dec 10, 2013 at 03:35:18PM -0800, Stephen Boyd wrote:

> >> +		reg += sizeof(u16);

> > I'd expect this to generate out of bounds accesses and bad interactions
> > on the bus if we go through the loop more than once since it appears to
> > incrementing the address of reg for every register.  I'm also having a

> ssbi_read() just reads the same register x number of times and doesn't
> do any sort of incrementing of address. My understanding was that
> regmap_bulk_read() will read incrementing addresses and then call down
> into this code with the sequential addresses formatted into the reg
> buffer. That was the flaw. Instead we need to take reg and then

That's possibly not the ideal decision for the underlying API, if
nothing else it's confusing naming given what a read function would
normally do.

> increment reg by 1 every time through this loop. Or should we just have
> use_single_rw == true?

No, it doesn't - it increments the address of reg by the size of a
register value each time.  Using use_single_rw might make sense, or if
you can't do bulk I/O at all then hooking in via reg_read() and
reg_write() in the config rather than trying to parse out the buffers
might be even better (you can still make helpers to set that up).

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  reply	other threads:[~2013-12-11  0:51 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-10 23:35 [PATCH 0/8] Modernize pm8921 with irqdomains + regmap Stephen Boyd
2013-12-10 23:35 ` [PATCH 1/8] mfd: ssbi: Remove platform data structs and hide ssbi type enum Stephen Boyd
2013-12-11  9:27   ` Lee Jones
2013-12-10 23:35 ` [PATCH 2/8] mfd: ssbi: Constify buffer in ssbi_write Stephen Boyd
2013-12-11  9:28   ` Lee Jones
2013-12-10 23:35 ` [PATCH 3/8] regmap: Add support for using regmap over ssbi Stephen Boyd
2013-12-10 23:50   ` Mark Brown
2013-12-11  0:13     ` Stephen Boyd
2013-12-11  0:51       ` Mark Brown [this message]
2013-12-11  1:32         ` Stephen Boyd
2013-12-11 13:27           ` Mark Brown
2013-12-12 23:13             ` Stephen Boyd
2013-12-13 10:41               ` Mark Brown
2013-12-13 17:14                 ` [PATCH] regmap: Allow regmap_bulk_read() to work for "no-bus" regmaps Stephen Boyd
2013-12-16 20:57                   ` Mark Brown
2013-12-13 21:37                 ` [PATCH 3/8] regmap: Add support for using regmap over ssbi Stephen Boyd
2013-12-16 21:01                   ` Mark Brown
2013-12-17  2:30                     ` [PATCH] regmap: Allow regmap_bulk_write() to work for "no-bus" regmaps Stephen Boyd
2013-12-18 18:45                       ` Mark Brown
2013-12-23 20:05                         ` Stephen Boyd
2013-12-24 12:53                           ` Mark Brown
2013-12-26 19:34                             ` Stephen Boyd
2013-12-26 21:52                               ` [PATCH v2] " Stephen Boyd
2013-12-30 12:42                                 ` Mark Brown
2013-12-10 23:35 ` [PATCH 4/8] mfd: ssbi: Mark match table const Stephen Boyd
2013-12-11  9:29   ` Lee Jones
2013-12-10 23:35 ` [PATCH 5/8] mfd: Move pm8xxx-irq.c contents into only driver that uses it Stephen Boyd
2013-12-11  9:35   ` Lee Jones
2013-12-12 19:06     ` Stephen Boyd
2013-12-10 23:35 ` [PATCH 6/8] mfd: pm8921: Update for genirq changes Stephen Boyd
2013-12-11  9:48   ` Lee Jones
2013-12-10 23:35 ` [PATCH 7/8] mfd: pm8921: Migrate to irqdomains Stephen Boyd
2013-12-11  9:53   ` Lee Jones
2013-12-11 21:30   ` Courtney Cavin
2013-12-12 19:05     ` Stephen Boyd
2013-12-10 23:35 ` [PATCH 8/8] mfd: pm8921: Use ssbi regmap Stephen Boyd
2013-12-11  9:55   ` Lee Jones

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