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

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Date:   Tue, 9 Jun 2020 10:19:08 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Jonathan Marek <jonathan@...ek.ca>, alsa-devel@...a-project.org
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Vinod Koul <vkoul@...nel.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 08/06/2020 21:43, Jonathan Marek wrote:
> Adds support for qcom soundwire devices with memory mapped IO registers.
> 
> Signed-off-by: Jonathan Marek <jonathan@...ek.ca>
> ---

In general patch itself looks pretty trivial, but I would like to see 
what 1.5.1 controller provides in terms of error reporting of SoundWire 
slave register reads/writes. On WCD based controller we did not have a 
mechanism to report things like if the read is ignored or not. I was 
hoping that this version of controller would be able to report that.

I will be nice to those patches if that is something which is supported 
in this version.

--srini

>   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;
> +}
> +
>   static int qcom_swrm_cmd_fifo_wr_cmd(struct qcom_swrm_ctrl *ctrl, u8 cmd_data,
>   				     u8 dev_addr, u16 reg_addr)
>   {
> @@ -746,6 +761,7 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>   	struct sdw_master_prop *prop;
>   	struct sdw_bus_params *params;
>   	struct qcom_swrm_ctrl *ctrl;
> +	struct resource *res;
>   	int ret;
>   	u32 val;
>   
> @@ -760,8 +776,13 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>   		if (!ctrl->regmap)
>   			return -EINVAL;
>   	} else {
> -		/* Only WCD based SoundWire controller is supported */
> -		return -ENOTSUPP;
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> +		ctrl->reg_read = qcom_swrm_cpu_reg_read;
> +		ctrl->reg_write = qcom_swrm_cpu_reg_write;
> +		ctrl->mmio = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(ctrl->mmio))
> +			return PTR_ERR(ctrl->mmio);
>   	}
>   
>   	ctrl->irq = of_irq_get(dev->of_node, 0);
>