linux-kernel - Re: [PATCH v2 1/4] clk: qcom: Clear hardware clock control bit of RCG

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Date:   Mon, 26 Mar 2018 10:49:47 +0530
From:   "Nischal, Amit" <anischal@...eaurora.org>
To:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>
Cc:     Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Odelu Kukatla <okukatla@...eaurora.org>,
        Taniya Das <tdas@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/4] clk: qcom: Clear hardware clock control bit of RCG



On 3/20/2018 4:25 AM, Stephen Boyd wrote:
> Quoting Amit Nischal (2018-03-07 23:18:12)
>> For upcoming targets like sdm845, POR value of the hardware clock control
>> bit is set for most of root clocks which needs to be cleared for software
>> to be able to control. For older targets like MSM8996, this bit is reserved
>> bit and having POR value as 0 so this patch will work for the older targets
>> too. So update the configuration mask to take care of the same to clear
>> hardware clock control bit.
>>
>> Signed-off-by: Amit Nischal <anischal@...eaurora.org>
>> ---
>>   drivers/clk/qcom/clk-rcg2.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
>> index bbeaf9c..e63db10 100644
>> --- a/drivers/clk/qcom/clk-rcg2.c
>> +++ b/drivers/clk/qcom/clk-rcg2.c
>> @@ -1,5 +1,5 @@
>>   /*
>> - * Copyright (c) 2013, The Linux Foundation. All rights reserved.
>> + * Copyright (c) 2013, 2018, The Linux Foundation. All rights reserved.
> It would be nice if lawyers over there could avoid forcing copyright
> date updates when less than half the file changes.

Thanks for the review.
I will address the above in the next patch series.

>
>>    *
>>    * This software is licensed under the terms of the GNU General Public
>>    * License version 2, as published by the Free Software Foundation, and
>> @@ -42,6 +42,7 @@
>>   #define CFG_MODE_SHIFT         12
>>   #define CFG_MODE_MASK          (0x3 << CFG_MODE_SHIFT)
>>   #define CFG_MODE_DUAL_EDGE     (0x2 << CFG_MODE_SHIFT)
>> +#define CFG_HW_CLK_CTRL_MASK   BIT(20)
>>
>>   #define M_REG                  0x8
>>   #define N_REG                  0xc
>> @@ -276,7 +277,7 @@ static int clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f)
>>          }
>>
>>          mask = BIT(rcg->hid_width) - 1;
>> -       mask |= CFG_SRC_SEL_MASK | CFG_MODE_MASK;
>> +       mask |= CFG_SRC_SEL_MASK | CFG_MODE_MASK | CFG_HW_CLK_CTRL_MASK;
>>          cfg = f->pre_div << CFG_SRC_DIV_SHIFT;
>>          cfg |= rcg->parent_map[index].cfg << CFG_SRC_SEL_SHIFT;
>>          if (rcg->mnd_width && f->n && (f->m != f->n))
> Is there going to be a future patch to update the RCGs to indicate they
> support hardware control or not?

As of now, there will not be any patch to update the RCGs to support HW control.