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Date: Fri, 22 May 2015 13:20:36 +0800
From: Bintian <bintian.wang@huawei.com>
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To: Stephen Boyd <sboyd@codeaurora.org>, <mturquette@linaro.org>,
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Subject: Re: [PATCH v7 6/7] clk: hi6220: Clock driver support for Hisilicon
 hi6220 SoC
References: <1432117752-7074-1-git-send-email-bintian.wang@huawei.com> <1432117752-7074-2-git-send-email-bintian.wang@huawei.com> <555D09F3.7020506@codeaurora.org> <555D57BB.8080702@huawei.com> <555E1D55.1050907@codeaurora.org>
In-Reply-To: <555E1D55.1050907@codeaurora.org>
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List-ID: <linux-clk.vger.kernel.org>

Hello Stephen,

On 2015/5/22 2:00, Stephen Boyd wrote:
> On 05/20/15 20:57, Bintian wrote:
>>
>>>
>>>>
>>>> +
>>>> +static void __init hi6220_clk_sys_init(struct device_node *np)
>>>> +{
>>>> +    struct hisi_clock_data *clk_data;
>>>> +
>>>> +    clk_data = hisi_clk_init(np, HI6220_SYS_NR_CLKS);
>>>> +    if (!clk_data)
>>>> +        return;
>>>> +
>>>> +    hisi_clk_register_gate_sep(hi6220_separated_gate_clks_sys,
>>>> +            ARRAY_SIZE(hi6220_separated_gate_clks_sys), clk_data);
>>>> +
>>>> +    hisi_clk_register_mux(hi6220_mux_clks_sys,
>>>> +            ARRAY_SIZE(hi6220_mux_clks_sys), clk_data);
>>>> +
>>>> +    hi6220_clk_register_divider(hi6220_div_clks_sys,
>>>> +            ARRAY_SIZE(hi6220_div_clks_sys), clk_data);
>>>> +
>>>> +    if (!clk_data_ao)
>>>> +        return;
>>>> +
>>>> +    /* enable high speed clock on UART1 mux */
>>>> +    clk_set_parent(clk_data->clk_data.clks[HI6220_UART1_SRC],
>>>> +            clk_data_ao->clk_data.clks[HI6220_150M]);
>>>
>>> Sorry I missed this one earlier. Can we do this clk_set_parent() through
>>> assigned-parents instead?
>> Uart1 has two clock parents in hi6220, and use "clk_tcxo" by default,
>> we use uart1 to connect BT in HiKey, and switch to "clk_150m" for high
>> speed mode of BT, but pl011 has no code to set clock rate or set clock
>> parents operation, so it's a easy way to do that here.
>
> Is pl011 the uart device? Does it have a node in DT somewhere? If it
> does, then we could put the assigned-parents properties in that node so
> that when the pl011 probes the uart1 clock has its parent set to
> clk_150m. See the "Assigned clock parents and rates" section of
> Documentation/devicetree/bindings/clock/clock-bindings.txt.
>
I will verify this.

If it is OK, I will remove "clk_set_parent" from this patch.

Thanks,

Bintian