From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751425AbdEaI2t (ORCPT ); Wed, 31 May 2017 04:28:49 -0400 Received: from mx07-00252a01.pphosted.com ([62.209.51.214]:52495 "EHLO mx07-00252a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996AbdEaI2q (ORCPT ); Wed, 31 May 2017 04:28:46 -0400 Subject: Re: [PATCH 1/2] clk: bcm2835: Limit PCM clock to OSC and PLLD_PER To: Stefan Wahren , linux-clk@vger.kernel.org, Eric Anholt , linux-kernel@vger.kernel.org, Michael Turquette , Stephen Boyd , Florian Fainelli , linux-rpi-kernel@lists.infradead.org References: <866b60bb-d1c8-726e-3a2d-11a34f9e8ac7@raspberrypi.org> <684006892.45085.1496169665454@email.1und1.de> From: Phil Elwell Message-ID: <56d5f9c5-ba15-4d3e-7956-fb697fe12114@raspberrypi.org> Date: Wed, 31 May 2017 09:28:31 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <684006892.45085.1496169665454@email.1und1.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-31_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_spam_notspam policy=outbound_spam score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705310156 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Stefan, On 30/05/2017 19:41, Stefan Wahren wrote: > Hi Phil, > >> Phil Elwell hat am 30. Mai 2017 um 18:28 geschrieben: >> >> >> Restrict clock sources for the PCM peripheral to the oscillator and >> PLLD_PER because other source may have varying rates or be switched off. > >> Prevent other sources from being selected by replacing their names in >> the list of potential parents with dummy entries (entry index is >> significant). > > i like to have this as a comment above the definition of bcm2835_pcm_per_parents. Sure - good idea. >> >> Signed-off-by: Phil Elwell >> --- >> drivers/clk/bcm/clk-bcm2835.c | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c >> index 0258538..facc346 100644 >> --- a/drivers/clk/bcm/clk-bcm2835.c >> +++ b/drivers/clk/bcm/clk-bcm2835.c >> @@ -1511,6 +1511,16 @@ struct bcm2835_clk_desc { >> "pllh_aux", >> }; >> >> +static const char *const bcm2835_pcm_per_parents[] = { > > As mentioned above, there should be a comment like all the others. Yes, will do. >> + "-", >> + "xosc", >> + "-", >> + "-", >> + "-", >> + "-", >> + "plld_per", >> +}; > > Is there a dummy entry for "pllh_aux" missing? Yes and no - adding it will cause an extra iteration around the loop, but perhaps it's less confusing. I'll add one. >> + >> #define REGISTER_PER_CLK(...) REGISTER_CLK( \ >> .num_mux_parents = ARRAY_SIZE(bcm2835_clock_per_parents), \ >> .parents = bcm2835_clock_per_parents, \ >> @@ -2000,6 +2010,7 @@ struct bcm2835_clk_desc { >> .int_bits = 12, >> .frac_bits = 12, >> .is_mash_clock = true, >> + .parents = bcm2835_pcm_per_parents, > > This looks a little bit hacky to me. Not sure, but can we do something like this? > > #define REGISTER_PCM_CLK(...) REGISTER_CLK( \ > .num_mux_parents = ARRAY_SIZE(bcm2835_pcm_per_parents), \ > .parents = bcm2835_pcm_per_parents, \ > __VA_ARGS__) Of course - no problem. Thanks for the feedback - it will be incorporated into V2. Phil