Re: [PATCH v2] clk: x86: Add ST oscout platform clock

[Agrawal, Akshu]

On 5/5/2018 7:56 AM, Stephen Boyd wrote:
> Quoting Akshu Agrawal (2018-05-03 01:30:26)
>> diff --git a/drivers/clk/x86/Makefile b/drivers/clk/x86/Makefile
>> index 1367afb..2aee002 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_AMD_PLATFORM_DEVICE)  += clk-st.o
> 
> Ok. Can you sort this by kconfig? Or by file name?
> 

Accepted.

>> diff --git a/drivers/clk/x86/clk-st.c b/drivers/clk/x86/clk-st.c
>> new file mode 100644
>> index 0000000..d8c283c
>> --- /dev/null
>> +++ b/drivers/clk/x86/clk-st.c
>> @@ -0,0 +1,86 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * 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.
> 
> One point of SPDX is to avoid this boiler plate multi-line license
> comments. Can you remove this and just leave the AMD copyright part?
> 

Accepted.

>> + */
>> +
>> +#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
>> +
>> +#define ST_CLK_48M     0
>> +#define ST_CLK_25M     1
>> +#define ST_CLK_MUX     2
>> +#define ST_CLK_GATE    3
>> +#define ST_MAX_CLKS    4
>> +
>> +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_hw **hws;
>> +
>> +       st_data = dev_get_platdata(&pdev->dev);
>> +       if (!st_data || !st_data->base)
>> +               return -EINVAL;
>> +
>> +       hws = kzalloc(sizeof(*hws) * ST_MAX_CLKS, GFP_KERNEL);
> 
> Fix the kbuild robot errors please.
>

Done in v3.

>> +
>> +       hws[ST_CLK_48M] = clk_hw_register_fixed_rate(NULL, "clk48MHz", NULL, 0,
>> +                                                    48000000);
>> +       hws[ST_CLK_25M] = clk_hw_register_fixed_rate(NULL, "clk25MHz", NULL, 0,
>> +                                                    25000000);
> 
> I'm not sure why we even keep these pointers around though. The driver
> doesn't expose them as clks that clk_get() can find so they could just
> be local variables and no heap allocation is needed.
> 

Respining the patch with change to unregister clk_hw in the remove callback.
Will pass these pointers as drvdata to remove and use them to unregister.

>> +
>> +       hws[ST_CLK_MUX] = clk_hw_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(hws[ST_CLK_MUX]->clk, hws[ST_CLK_25M]->clk);
>> +
>> +       hws[ST_CLK_GATE] = clk_hw_register_gate(NULL, "oscout1", "oscout1_mux",
>> +               0, st_data->base + MISCCLKCNTL1, OSCCLKENB,
>> +               CLK_GATE_SET_TO_DISABLE, NULL);
>> +
>> +       clk_hw_register_clkdev(hws[ST_CLK_GATE], "oscout1", NULL);
> 
> Could use devm_*() here in case you want to drop this stuff on driver
> removal?
> 

To achieve the same what you have suggested, I would be using remove as
explained in above comment.

>> +
>> +       return 0;
>> +}
>> +
>> +static struct platform_driver st_clk_driver = {
>> +       .driver = {
>> +               .name = "clk-st",
>> +       },
>> +       .probe = st_clk_probe,
> 
> suppress attributes here to prevent unbinding from sysfs?
> 

Accepted.

Thanks,
Akshu