From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Felipe Balbi <balbi@ti.com>
Cc: ben-linux@fluff.org, Tony Lindgren <tony@atomide.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
w.sang@pengutronix.de, linux-i2c@vger.kernel.org,
Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
Linux ARM Kernel Mailing List
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 04/17] i2c: omap: simplify omap_i2c_ack_stat()
Date: Thu, 14 Jun 2012 12:13:33 +0100 [thread overview]
Message-ID: <20120614111333.GA31187@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1339669250-9183-5-git-send-email-balbi@ti.com>
On Thu, Jun 14, 2012 at 01:20:37PM +0300, Felipe Balbi wrote:
> stat & BIT(1) is the same as BIT(1), so let's
> simplify things a bit by removing "stat &" from
> all omap_i2c_ack_stat() calls.
This doesn't feel right, and the explanation is definitely wrong.
"stat & BIT(1)" is not the same as "BIT(1)" _unless_ you're saying that
stat always has BIT(1) already set. Can you guarantee that in this code?
If so, how?
What happens if you read the status register, and it has bit 1 clear.
immediately after the read, the status register bit 1 becomes set, and
then you write bit 1 set (because you've dropped the stat & BIT(1) from
the code.)
Is it not going to acknowledge that bit-1-set but because you haven't
read it, you're going to miss that event?
This feels like a buggy change to me.
next prev parent reply other threads:[~2012-06-14 11:13 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-14 10:20 [PATCH 00/17] Big OMAP I2C Cleanup Felipe Balbi
2012-06-14 10:20 ` [PATCH 01/17] i2c: omap: simplify num_bytes handling Felipe Balbi
[not found] ` <1339669250-9183-2-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 10:33 ` Shilimkar, Santosh
2012-06-14 10:20 ` [PATCH 02/17] i2c: omap: decrease indentation level on data handling Felipe Balbi
[not found] ` <1339669250-9183-3-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 10:41 ` Shilimkar, Santosh
2012-06-14 10:40 ` Felipe Balbi
2012-06-14 10:20 ` [PATCH 03/17] i2c: omap: add blank lines Felipe Balbi
[not found] ` <1339669250-9183-4-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 10:43 ` Shilimkar, Santosh
2012-06-14 10:20 ` [PATCH 05/17] i2c: omap: split out [XR]DR and [XR]RDY Felipe Balbi
2012-06-14 10:20 ` [PATCH 07/17] i2c: omap: re-factor receive/transmit data loop Felipe Balbi
2012-06-14 10:20 ` [PATCH 09/17] i2c: omap: ack IRQ in parts Felipe Balbi
2012-06-14 11:11 ` Shilimkar, Santosh
2012-06-14 11:46 ` Felipe Balbi
2012-06-14 11:20 ` Russell King - ARM Linux
[not found] ` <20120614112017.GC31187-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2012-06-14 11:47 ` Felipe Balbi
2012-06-14 10:20 ` [PATCH 10/17] i2c: omap: get rid of the "complete" label Felipe Balbi
2012-06-14 10:20 ` [PATCH 11/17] i2c: omap: switch to devm_* API Felipe Balbi
2012-06-14 10:20 ` [PATCH 12/17] i2c: omap: switch to platform_get_irq() Felipe Balbi
2012-06-14 10:20 ` [PATCH 14/17] i2c: omap: simplify errata check Felipe Balbi
2012-06-14 10:20 ` [PATCH 15/17] i2c: omap: always return IRQ_HANDLED Felipe Balbi
[not found] ` <1339669250-9183-16-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 11:18 ` Shilimkar, Santosh
2012-06-14 11:23 ` Russell King - ARM Linux
[not found] ` <20120614112323.GD31187-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2012-06-14 11:25 ` Shilimkar, Santosh
2012-06-14 10:20 ` [PATCH 17/17] i2c: omap: resize fifos before each message Felipe Balbi
[not found] ` <1339669250-9183-1-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 10:20 ` [PATCH 04/17] i2c: omap: simplify omap_i2c_ack_stat() Felipe Balbi
[not found] ` <1339669250-9183-5-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 10:45 ` Shilimkar, Santosh
2012-06-14 11:13 ` Russell King - ARM Linux [this message]
2012-06-14 11:45 ` Felipe Balbi
2012-06-14 10:20 ` [PATCH 06/17] i2c: omap: improve 1p153 errata handling Felipe Balbi
2012-06-14 11:01 ` Shilimkar, Santosh
2012-06-14 11:17 ` Russell King - ARM Linux
[not found] ` <20120614111746.GB31187-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2012-06-14 11:48 ` Felipe Balbi
2012-06-14 10:20 ` [PATCH 08/17] i2c: omap: switch over to do {} while loop Felipe Balbi
[not found] ` <1339669250-9183-9-git-send-email-balbi-l0cyMroinI0@public.gmane.org>
2012-06-14 11:03 ` Shilimkar, Santosh
2012-06-14 11:05 ` Felipe Balbi
2012-06-14 10:20 ` [PATCH 13/17] i2c: omap: bus: add a receiver flag Felipe Balbi
2012-06-14 10:20 ` [PATCH 16/17] i2c: omap: simplify IRQ exit path Felipe Balbi
2012-06-14 11:23 ` [PATCH 00/17] Big OMAP I2C Cleanup Shilimkar, Santosh
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