Re: [PATCHv3] w1: omap-hdq: Simplify driver with PM runtime autosuspend

From: Tony Lindgren <tony@atomide.com>
To: "H. Nikolaus Schaller" <hns@goldelico.com>
Cc: Andreas Kemnade <andreas@kemnade.info>,
	Evgeniy Polyakov <zbr@ioremap.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-omap <linux-omap@vger.kernel.org>,
	Adam Ford <aford173@gmail.com>, "Andrew F . Davis" <afd@ti.com>,
	Vignesh R <vigneshr@ti.com>
Subject: Re: [PATCHv3] w1: omap-hdq: Simplify driver with PM runtime autosuspend
Date: Wed, 29 Apr 2020 14:38:17 -0700	[thread overview]
Message-ID: <20200429213817.GU37466@atomide.com> (raw)
In-Reply-To: <891CBD28-3F91-493D-AD80-6575608846A4@goldelico.com>

* H. Nikolaus Schaller <hns@goldelico.com> [200429 21:35]:
> I have reworked the way the spinlocks, setting and resetting
> of the hdq_irqstatus bits are done and now it works right from
> start of boot. Without any timeouts or delays.
> 
> I am not exactly sure what went wrong, but it seems as if
> the read is already done when the write interrupt status
> bit is processed. Then, the old logic did wipe out both
> bits by hdq_reset_irqstatus() and the read code did timeout
> because it did not notice that the data had already been
> available. This may depend on other system activities so
> that it can explain why other tests didn't reveal it.
> 
> omap_hdq_runtime_resume() and omap_hdq_runtime_suspend()
> also behave fine.
> 
> Before I can post something I need to clean up my hacks
> and add similar fixes to omap_hdq_break() and omap_w1_triplet()
> where I hope that I don't break those...

OK good to hear you were able to figure out what is
going on here.

Regards,

Tony