Re: [PATCH v3 6/9] media: cadence: Add operation on reset

Jack Zhu
2023-04-07T06:30:33Z

On 2023/4/4 13:06, Laurent Pinchart wrote:
> Hi Jack,
>
> Thank you for the patch.
>
> On Fri, Mar 31, 2023 at 08:18:23PM +0800, Jack Zhu wrote:
>> Add operation on reset for Cadence MIPI-CSI2 RX Controller.
>>
>> Signed-off-by: Jack Zhu <jack.zhu@starfivetech.com>
>> ---
>> drivers/media/platform/cadence/cdns-csi2rx.c | 30 ++++++++++++++++++++
>> 1 file changed, 30 insertions(+)
>>
>> diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
>> index cc3ebb0d96f6..a1555cedb349 100644
>> --- a/drivers/media/platform/cadence/cdns-csi2rx.c
>> +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
>> @@ -13,6 +13,7 @@
>> #include <linux/of_graph.h>
>> #include <linux/phy/phy.h>
>> #include <linux/platform_device.h>
>> +#include <linux/reset.h>
>> #include <linux/slab.h>
>>
>> #include <media/v4l2-ctrls.h>
>> @@ -68,6 +69,9 @@ struct csi2rx_priv {
>> struct clk *sys_clk;
>> struct clk *p_clk;
>> struct clk *pixel_clk[CSI2RX_STREAMS_MAX];
>> + struct reset_control *sys_rst;
>> + struct reset_control *p_rst;
>> + struct reset_control *pixel_rst[CSI2RX_STREAMS_MAX];
>> struct phy *dphy;
>>
>> u8 lanes[CSI2RX_LANES_MAX];
>> @@ -112,6 +116,7 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>> if (ret)
>> return ret;
>>
>> + reset_control_deassert(csi2rx->p_rst);
>> csi2rx_reset(csi2rx);
>>
>> reg = csi2rx->num_lanes << 8;
>> @@ -154,6 +159,8 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>> if (ret)
>> goto err_disable_pixclk;
>
> The loop after the err_disable_pixclk label should assert the
> pixel_rst[i] reset.
>

OK, I will fix it.

>>
>> + reset_control_deassert(csi2rx->pixel_rst[i]);
>> +
>> writel(CSI2RX_STREAM_CFG_FIFO_MODE_LARGE_BUF,
>> csi2rx->base + CSI2RX_STREAM_CFG_REG(i));
>>
>> @@ -169,6 +176,7 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>> if (ret)
>> goto err_disable_pixclk;
>>
>> + reset_control_deassert(csi2rx->sys_rst);
>> clk_disable_unprepare(csi2rx->p_clk);
>>
>> return 0;
>> @@ -188,14 +196,17 @@ static void csi2rx_stop(struct csi2rx_priv *csi2rx)
>> unsigned int i;
>>
>> clk_prepare_enable(csi2rx->p_clk);
>> + reset_control_assert(csi2rx->sys_rst);
>> clk_disable_unprepare(csi2rx->sys_clk);
>>
>> for (i = 0; i < csi2rx->max_streams; i++) {
>> writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
>>
>> + reset_control_assert(csi2rx->pixel_rst[i]);
>> clk_disable_unprepare(csi2rx->pixel_clk[i]);
>> }
>>
>> + reset_control_assert(csi2rx->p_rst);
>> clk_disable_unprepare(csi2rx->p_clk);
>>
>> if (v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, false))
>> @@ -299,6 +310,17 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
>> return PTR_ERR(csi2rx->p_clk);
>> }
>>
>> + csi2rx->sys_rst =
>> + devm_reset_control_get_optional_exclusive(&pdev->dev,
>> + "sys_rst");
>
> You can write this on two lines:
>
> csi2rx->sys_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
> "sys_rst");

OK, I will modify it.

>> + if (IS_ERR(csi2rx->sys_rst))
>> + return PTR_ERR(csi2rx->sys_rst);
>> +
>> + csi2rx->p_rst =
>> + devm_reset_control_get_optional_exclusive(&pdev->dev, "p_rst");
>
> And here,
>
> csi2rx->p_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
> "p_rst");
>
> would be the same number of lines but more readable in my opinion.
>

OK, I will modify it.

>> + if (IS_ERR(csi2rx->p_rst))
>> + return PTR_ERR(csi2rx->p_rst);
>> +
>> csi2rx->dphy = devm_phy_optional_get(&pdev->dev, "dphy");
>> if (IS_ERR(csi2rx->dphy)) {
>> dev_err(&pdev->dev, "Couldn't get external D-PHY\n");
>> @@ -350,6 +372,7 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
>>
>> for (i = 0; i < csi2rx->max_streams; i++) {
>> char clk_name[16];
>> + char rst_name[16];
>
> You don't need two variables, you can rename clk_name to name, and use
> it for both clk and rst.
>

OK, I will fix it.

> With these small issues addressed you can add my
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> in the next version.
>
OK. Thank you for your review.

>>
>> snprintf(clk_name, sizeof(clk_name), "pixel_if%u_clk", i);
>> csi2rx->pixel_clk[i] = devm_clk_get(&pdev->dev, clk_name);
>> @@ -357,6 +380,13 @@ static int csi2rx_get_resources(struct csi2rx_priv *csi2rx,
>> dev_err(&pdev->dev, "Couldn't get clock %s\n", clk_name);
>> return PTR_ERR(csi2rx->pixel_clk[i]);
>> }
>> +
>> + snprintf(rst_name, sizeof(rst_name), "pixel_if%u_rst", i);
>> + csi2rx->pixel_rst[i] =
>> + devm_reset_control_get_optional_exclusive(&pdev->dev,
>> + rst_name);
>> + if (IS_ERR(csi2rx->pixel_rst[i]))
>> + return PTR_ERR(csi2rx->pixel_rst[i]);
>> }
>>
>> return 0;
>