From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752941AbcKIJwE (ORCPT ); Wed, 9 Nov 2016 04:52:04 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:49746 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751332AbcKIJwA (ORCPT ); Wed, 9 Nov 2016 04:52:00 -0500 Subject: Re: [PATCH 1/6] clk: stm32f4: Add PLL_I2S & PLL_SAI for STM32F429/469 boards To: =?UTF-8?Q?Rados=c5=82aw_Pietrzyk?= References: <1478523943-23142-1-git-send-email-gabriel.fernandez@st.com> <1478523943-23142-2-git-send-email-gabriel.fernandez@st.com> <0368d067-461d-2edb-5561-9717934e0dde@st.com> CC: Rob Herring , Mark Rutland , Russell King , Maxime Coquelin , Alexandre Torgue , Michael Turquette , Stephen Boyd , Nicolas Pitre , Arnd Bergmann , Daniel Thompson , Andrea Merello , , , , , , , , From: Gabriel Fernandez Message-ID: Date: Wed, 9 Nov 2016 10:51:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.48.1.80] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-11-09_03:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/09/2016 09:10 AM, Radosław Pietrzyk wrote: > I would expect that VCO clock will force recalculation for all its > children if I am not mistaken. Sure BR Gabriel. > > 2016-11-08 17:19 GMT+01:00 Gabriel Fernandez : >> On 11/08/2016 09:52 AM, Radosław Pietrzyk wrote: >>> 2016-11-08 9:35 GMT+01:00 Gabriel Fernandez : >>>> Hi Radosław >>>> >>>> Many thanks for reviewing. >>>> >>>> On 11/07/2016 03:57 PM, Radosław Pietrzyk wrote: >>>>>> +static struct clk_hw *clk_register_pll_div(const char *name, >>>>>> + const char *parent_name, unsigned long flags, >>>>>> + void __iomem *reg, u8 shift, u8 width, >>>>>> + u8 clk_divider_flags, const struct clk_div_table >>>>>> *table, >>>>>> + struct clk_hw *pll_hw, spinlock_t *lock) >>>>>> +{ >>>>>> + struct stm32f4_pll_div *pll_div; >>>>>> + struct clk_hw *hw; >>>>>> + struct clk_init_data init; >>>>>> + int ret; >>>>>> + >>>>>> + /* allocate the divider */ >>>>>> + pll_div = kzalloc(sizeof(*pll_div), GFP_KERNEL); >>>>>> + if (!pll_div) >>>>>> + return ERR_PTR(-ENOMEM); >>>>>> + >>>>>> + init.name = name; >>>>>> + init.ops = &stm32f4_pll_div_ops; >>>>>> + init.flags = flags; >>>>> Maybe it's worth to have CLK_SET_RATE_PARENT here and the VCO clock >>>>> should have CLK_SET_RATE_GATE flag and we can get rid of custom >>>>> divider ops. >>>> I don't want to offer the possibility to change the vco clock through the >>>> divisor of the pll (only by a boot-loader or by DT). >>>> >>>> e.g. if i make a set rate on lcd-tft clock, i don't want to change the >>>> SAI >>>> frequencies. >>>> >>>> I used same structure for internal divisors of the pll (p, q, r) and for >>>> post divisors (plli2s-q-div, pllsai-q-div & pllsai-r-div). >>>> That why the CLK_SET_RATE_PARENT flag is transmit by parameter. >>>> >>>> These divisors are similar because we have to switch off the pll before >>>> changing the rate. >>>> >>> But changing pll and lcd dividers only may not be enough for getting >>> very specific pixelclocks and that might require changing the VCO >>> frequency itself. The rest of the SAI tree should be recalculated >>> then. >> I agree but it seems to be too much complicated to recalculate all PLL >> divisors if we change the vco clock. >> You mean to use Clock notifier callback ?