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Subject: Re: [PATCH] clk: x86: Add ST oscout platform clock
To:     Stephen Boyd <sboyd@kernel.org>
Cc:     djkurtz@chromium.org, Alexander.Deucher@amd.com,
        Michael Turquette <mturquette@baylibre.com>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        Dave Airlie <airlied@redhat.com>,
        Shaoyun Liu <Shaoyun.Liu@amd.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:COMMON CLK FRAMEWORK" <linux-clk@vger.kernel.org>
References: <1525072055-17898-1-git-send-email-akshu.agrawal@amd.com>
 <152521188500.138124.10561048787941050422@swboyd.mtv.corp.google.com>
From:   "Agrawal, Akshu" <Akshu.Agrawal@amd.com>
Message-ID: <b8fc236e-032b-7806-e44c-0bbe9faefc66@amd.com>
Date:   Thu, 3 May 2018 13:45:05 +0530
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On 5/2/2018 3:28 AM, Stephen Boyd wrote:
> Quoting Akshu Agrawal (2018-04-30 00:06:53)
>> diff --git a/drivers/clk/x86/Makefile b/drivers/clk/x86/Makefile
>> index 1367afb..f7ebae1 100644
>> --- a/drivers/clk/x86/Makefile
>> +++ b/drivers/clk/x86/Makefile
>> @@ -1,3 +1,4 @@
>>   clk-x86-lpss-objs              := clk-lpt.o
>>   obj-$(CONFIG_X86_INTEL_LPSS)   += clk-x86-lpss.o
>>   obj-$(CONFIG_PMC_ATOM)         += clk-pmc-atom.o
>> +obj-$(CONFIG_X86)              += clk-st.o
> 
> No desire to make a Kconfig for this driver so it isn't included all the
> time on x86 devices that don't have this hardware?
> 

Accepted, will use AMD specific config.

>> diff --git a/drivers/clk/x86/clk-st.c b/drivers/clk/x86/clk-st.c
>> new file mode 100644
>> index 0000000..6ac0dc5
>> --- /dev/null
>> +++ b/drivers/clk/x86/clk-st.c
>> @@ -0,0 +1,80 @@
>> +/*
>> + * clock framework for AMD Stoney based clocks
>> + *
>> + * Copyright 2018 Advanced Micro Devices, Inc.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
> 
> Can you use the SPDX tags here?
> 

Accepted. Will add in v2.

>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/clkdev.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/platform_data/clk-st.h>
>> +#include <linux/platform_device.h>
>> +
>> +/* Clock Driving Strength 2 register */
>> +#define CLKDRVSTR2     0x28
>> +/* Clock Control 1 register */
>> +#define MISCCLKCNTL1   0x40
>> +/* Auxiliary clock1 enable bit */
>> +#define OSCCLKENB      2
>> +/* 25Mhz auxiliary output clock freq bit */
>> +#define OSCOUT1CLK25MHZ        16
>> +
>> +static const char * const clk_oscout1_parents[] = { "clk48MHz", "clk25MHz" };
>> +
>> +static int st_clk_probe(struct platform_device *pdev)
>> +{
>> +       struct st_clk_data *st_data;
>> +       struct clk *clk_48m;
>> +       struct clk *clk_25m;
>> +       struct clk *clk_oscout1_mux;
>> +       struct clk *clk_oscout1;
>> +
>> +       st_data = dev_get_platdata(&pdev->dev);
>> +       if (!st_data || !st_data->base)
>> +               return -EINVAL;
>> +
>> +       clk_48m = clk_register_fixed_rate(NULL, "clk48MHz", NULL, 0,
>> +                                         48000000);
>> +       clk_25m = clk_register_fixed_rate(NULL, "clk25MHz", NULL, 0,
>> +                                         25000000);
>> +
>> +       clk_oscout1_mux = clk_register_mux(NULL, "oscout1_mux",
>> +               clk_oscout1_parents, ARRAY_SIZE(clk_oscout1_parents),
>> +               0, st_data->base + CLKDRVSTR2, OSCOUT1CLK25MHZ, 3, 0, NULL);
>> +
>> +       clk_set_parent(clk_oscout1_mux, clk_25m);
>> +
>> +       clk_oscout1 = clk_register_gate(NULL, "oscout1", "oscout1_mux",
>> +               0, st_data->base + MISCCLKCNTL1, OSCCLKENB,
>> +               CLK_GATE_SET_TO_DISABLE, NULL);
>> +
>> +       clk_register_clkdev(clk_oscout1, "oscout1", NULL);
> 
> Can you use the clk_hw registration and clkdev APIs? It would mean that
> clk_set_parent() call up above would still be needed but I guess that's
> OK. We don't currently have a way for non-DT based drivers to configure
> the parents of a clk when it's registered.
> 

Accepted, Changing in v2 to use clk_hw_register_.

>> +
>> +       return 0;
>> +}
>> +
>> diff --git a/include/linux/platform_data/clk-st.h b/include/linux/platform_data/clk-st.h
>> new file mode 100644
>> index 0000000..5ede980
>> --- /dev/null
>> +++ b/include/linux/platform_data/clk-st.h
>> @@ -0,0 +1,32 @@
>> +/*
>> + * clock framework for AMD Stoney based clock
>> + *
>> + * Copyright 2018 Advanced Micro Devices, Inc.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
>> + */
>> +
>> +#ifndef __CLK_ST_H
>> +#define __CLK_ST_H
>> +
>> +struct st_clk_data {
>> +       void __iomem *base;
> 
> Can you include compiler.h in this file for the __iomem usage?
> 

Accepted. Will add in v2.

Thanks,
Akshu