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

Pierre-Louis Bossart
2020-06-08T21:45:18Z

On 6/8/20 3:43 PM, Jonathan Marek wrote:
> Adds support for qcom soundwire devices with memory mapped IO registers.

'device' is an ambiguous term for SoundWire.

Seems to me this is a SoundWire Master device directly accessed with
mmio registers instead of over a SLIMbus link?

>
> Signed-off-by: Jonathan Marek <jonathan@marek.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;
> +}
> +
> 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;

I would move patch4 before this one, and add the functionality *after*
removing the SLIMbus dependency.

> + 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);

maybe deal with the resource checks before setting callbacks?

There are quite a few drivers who do things this way:

clk/qcom/common.c- res = platform_get_resource(pdev,
IORESOURCE_MEM, 0);
clk/qcom/common.c: base = devm_ioremap_resource(dev, res);
--

> }
>
> ctrl->irq = of_irq_get(dev->of_node, 0);
>