linux-kernel - Re: [PATCH 2/5] soundwire: qcom: add support for mmio soundwire devices

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Message-ID: <bbb552ce-4b13-0395-e1bc-0b6c5766f4ae@linaro.org>
Date:   Tue, 9 Jun 2020 10:18:35 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Vinod Koul <vkoul@...nel.org>, Jonathan Marek <jonathan@...ek.ca>
Cc:     alsa-devel@...a-project.org, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Sanyog Kale <sanyog.r.kale@...el.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/5] soundwire: qcom: add support for mmio soundwire
 devices



On 09/06/2020 05:34, Vinod Koul wrote:
> Hi Jonathan,
> 
> On 08-06-20, 16:43, Jonathan Marek wrote:
>> Adds support for qcom soundwire devices with memory mapped IO registers.
> 
> Please use 'SoundWire Master devices' instead :)
> 
>>
>> Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
>> ---
>>   drivers/soundwire/qcom.c | 25 +++++++++++++++++++++++--
>>   1 file changed, 23 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
>> index f38d1fd3679f..628747df1c75 100644
>> --- a/drivers/soundwire/qcom.c
>> +++ b/drivers/soundwire/qcom.c
>> @@ -90,6 +90,7 @@ struct qcom_swrm_ctrl {
>>   	struct sdw_bus bus;
>>   	struct device *dev;
>>   	struct regmap *regmap;
>> +	void __iomem *mmio;
>>   	struct completion *comp;
>>   	struct work_struct slave_work;
>>   	/* read/write lock */
>> @@ -154,6 +155,20 @@ static int qcom_swrm_ahb_reg_write(struct qcom_swrm_ctrl *ctrl,
>>   	return SDW_CMD_OK;
>>   }
>>   
>> +static int qcom_swrm_cpu_reg_read(struct qcom_swrm_ctrl *ctrl, int reg,
>> +				  u32 *val)
>> +{
>> +	*val = readl(ctrl->mmio + reg);
>> +	return SDW_CMD_OK;
>> +}
>> +
>> +static int qcom_swrm_cpu_reg_write(struct qcom_swrm_ctrl *ctrl, int reg,
>> +				   int val)
>> +{
>> +	writel(val, ctrl->mmio + reg);
>> +	return SDW_CMD_OK;
>> +}
> 
> this looks fine but regmap supports mmio also, so I am thinking we
> should remove these and set regmap (mmio/slim)... Srini..?

That is doable, but not going to add great value in this case, unless we 
are having another layer of abstraction. So keeping it as readl/writel 
seems okay to me.

--srini


>