[U-Boot] [PATCH 07/11] clk: Add fixed-factor clock driver

Alexander Graf
2019-01-21T14:19:03Z

On 01/18/2019 07:14 AM, Anup Patel wrote:
>
>> -----Original Message-----
>> From: Alexander Graf [mailto:agraf at suse.de]
>> Sent: Thursday, January 17, 2019 11:51 PM
>> To: Anup Patel <Anup.Patel@wdc.com>; Rick Chen <rick@andestech.com>;
>> Bin Meng <bmeng.cn@gmail.com>; Joe Hershberger
>> <joe.hershberger@ni.com>; Lukas Auer <lukas.auer@aisec.fraunhofer.de>;
>> Masahiro Yamada <yamada.masahiro@socionext.com>; Simon Glass
>> <sjg@chromium.org>
>> Cc: Palmer Dabbelt <palmer@sifive.com>; Paul Walmsley
>> <paul.walmsley@sifive.com>; Atish Patra <Atish.Patra@wdc.com>;
>> Christoph Hellwig <hch@infradead.org>; U-Boot Mailing List <u-
>> boot at lists.denx.de>
>> Subject: Re: [PATCH 07/11] clk: Add fixed-factor clock driver
>>
>> On 01/17/2019 11:39 AM, Anup Patel wrote:
>>> This patch adds fixed-factor clock driver which derives clock rate by
>>> dividing (div) and multiplying (mult) fixed factors to a parent clock.
>>>
>>> Signed-off-by: Anup Patel <anup.patel@wdc.com>
>>> Signed-off-by: Atish Patra <atish.patra@wdc.com>
>>> ---
>>> drivers/clk/Makefile | 4 +-
>>> drivers/clk/clk_fixed_factor.c | 74
>> ++++++++++++++++++++++++++++++++++
>>> 2 files changed, 77 insertions(+), 1 deletion(-)
>>> create mode 100644 drivers/clk/clk_fixed_factor.c
>>>
>>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index
>>> 2f4446568c..fa59259ea3 100644
>>> --- a/drivers/clk/Makefile
>>> +++ b/drivers/clk/Makefile
>>> @@ -4,7 +4,9 @@
>>> # Wolfgang Denk, DENX Software Engineering, wd at denx.de.
>>> #
>>>
>>> -obj-$(CONFIG_$(SPL_TPL_)CLK) += clk-uclass.o clk_fixed_rate.o
>>> +obj-$(CONFIG_$(SPL_TPL_)CLK) += clk-uclass.o
>>> +obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_rate.o
>>> +obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_factor.o
>>>
>>> obj-y += imx/
>>> obj-y += tegra/
>>> diff --git a/drivers/clk/clk_fixed_factor.c
>>> b/drivers/clk/clk_fixed_factor.c new file mode 100644 index
>>> 0000000000..eab1724c26
>>> --- /dev/null
>>> +++ b/drivers/clk/clk_fixed_factor.c
>>> @@ -0,0 +1,74 @@
>>> +// SPDX-License-Identifier: GPL-2.0+
>>> +/*
>>> + * Copyright (c) 2019 Western Digital Corporation or its affiliates.
>>> + *
>>> + * Author: Anup Patel <anup.patel@wdc.com> */
>>> +
>>> +#include <common.h>
>>> +#include <clk-uclass.h>
>>> +#include <div64.h>
>>> +#include <dm.h>
>>> +
>>> +struct clk_fixed_factor {
>>> + struct clk parent;
>>> + unsigned int div;
>>> + unsigned int mult;
>>> +};
>>> +
>>> +#define to_clk_fixed_factor(dev) \
>>> + ((struct clk_fixed_factor *)dev_get_platdata(dev))
>>> +
>>> +static ulong clk_fixed_factor_get_rate(struct clk *clk) {
>>> + int ret;
>>> + struct clk_fixed_factor *ff = to_clk_fixed_factor(clk->dev);
>>> +
>>> + if (clk->id != 0)
>>> + return -EINVAL;
>>> +
>>> + ret = clk_get_rate(&ff->parent);
>>> + if (IS_ERR_VALUE(ret))
>>> + return ret;
>>> +
>>> + do_div(ret, ff->div);
>>> +
>>> + return ret * ff->mult;
>>> +}
>>> +
>>> +const struct clk_ops clk_fixed_factor_ops = {
>>> + .get_rate = clk_fixed_factor_get_rate, };
>>> +
>>> +static int clk_fixed_factor_ofdata_to_platdata(struct udevice *dev) {
>>> +#if !CONFIG_IS_ENABLED(OF_PLATDATA)
>> Why do you need this?
> This is for boards/configuration where OF_PLATDATA is not enabled. For such boards, the board support code will provide platdata.
>
> I saw similar thing in clk_fixed_rate.c too hence kept it here. Do you want me to drop this "#if"?

I would prefer if we don't advocate OF_PLATDATA more than we have to. So
I'm all for making it harder to use it :). In other words, yes, please
drop support for it for now.

Alex