Hi Niklas,
ah, ups, this was maybe the patch the other one I just reviewed was
based on... sorry, I missed this one :)
On Sat, Feb 16, 2019 at 11:56:38PM +0100, Niklas Söderlund wrote:
> Later versions of the datasheet updates the reset procedure to more
> closely resemble the standby mode. Update the driver to enter and exit
> the standby mode instead of resetting the hardware before and after
> streaming is started and stopped.
>
> While at it break out the full start and stop procedures from
> rcsi2_s_stream() into the existing helper functions.
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> ---
> drivers/media/platform/rcar-vin/rcar-csi2.c | 69 +++++++++++++--------
> 1 file changed, 42 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> index f64528d2be3c95dd..f3099f3e536d808a 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -14,6 +14,7 @@
> #include <linux/of_graph.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> #include <linux/sys_soc.h>
>
> #include <media/v4l2-ctrls.h>
> @@ -350,6 +351,7 @@ struct rcar_csi2 {
> struct device *dev;
> void __iomem *base;
> const struct rcar_csi2_info *info;
> + struct reset_control *rstc;
>
> struct v4l2_subdev subdev;
> struct media_pad pads[NR_OF_RCAR_CSI2_PAD];
> @@ -387,11 +389,19 @@ static void rcsi2_write(struct rcar_csi2 *priv, unsigned int reg, u32 data)
> iowrite32(data, priv->base + reg);
> }
>
> -static void rcsi2_reset(struct rcar_csi2 *priv)
> +static void rcsi2_standby_mode(struct rcar_csi2 *priv, int on)
> {
> - rcsi2_write(priv, SRST_REG, SRST_SRST);
> + if (!on) {
minor thing: if (!on) { "wakeup"; } is confusing. What if you call the
variable "standby" or just "off" ?
> + pm_runtime_get_sync(priv->dev);
> + reset_control_deassert(priv->rstc);
> + return;
> + }
> +
> + rcsi2_write(priv, PHYCNT_REG, 0);
> + rcsi2_write(priv, PHTC_REG, PHTC_TESTCLR);
> + reset_control_assert(priv->rstc);
> usleep_range(100, 150);
> - rcsi2_write(priv, SRST_REG, 0);
> + pm_runtime_put(priv->dev);
> }
>
> static int rcsi2_wait_phy_start(struct rcar_csi2 *priv)
> @@ -462,7 +472,7 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp)
> return mbps;
> }
>
> -static int rcsi2_start(struct rcar_csi2 *priv)
> +static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> {
> const struct rcar_csi2_format *format;
> u32 phycnt, vcdt = 0, vcdt2 = 0;
> @@ -506,7 +516,6 @@ static int rcsi2_start(struct rcar_csi2 *priv)
>
> /* Init */
> rcsi2_write(priv, TREF_REG, TREF_TREF);
> - rcsi2_reset(priv);
> rcsi2_write(priv, PHTC_REG, 0);
>
> /* Configure */
> @@ -564,19 +573,36 @@ static int rcsi2_start(struct rcar_csi2 *priv)
> return 0;
> }
>
> +static int rcsi2_start(struct rcar_csi2 *priv)
> +{
> + int ret;
> +
> + rcsi2_standby_mode(priv, 0);
> +
> + ret = rcsi2_start_receiver(priv);
> + if (ret) {
> + rcsi2_standby_mode(priv, 1);
> + return ret;
> + }
> +
> + ret = v4l2_subdev_call(priv->remote, video, s_stream, 1);
minor thing as well, but I feel this one was better where it was, so
that "rcsi2_start()" only handles the hardware, while s_stream handles
the pipeline. But then _start() and _stop() becomes very short... so
yeah, feel free to keep it the way it is.
> + if (ret) {
> + rcsi2_standby_mode(priv, 1);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static void rcsi2_stop(struct rcar_csi2 *priv)
> {
> - rcsi2_write(priv, PHYCNT_REG, 0);
> -
> - rcsi2_reset(priv);
> -
> - rcsi2_write(priv, PHTC_REG, PHTC_TESTCLR);
> + v4l2_subdev_call(priv->remote, video, s_stream, 0);
> + rcsi2_standby_mode(priv, 1);
> }
>
> static int rcsi2_s_stream(struct v4l2_subdev *sd, int enable)
> {
> struct rcar_csi2 *priv = sd_to_csi2(sd);
> - struct v4l2_subdev *nextsd;
> int ret = 0;
>
> mutex_lock(&priv->lock);
> @@ -586,27 +612,12 @@ static int rcsi2_s_stream(struct v4l2_subdev *sd, int enable)
> goto out;
> }
>
> - nextsd = priv->remote;
> -
> if (enable && priv->stream_count == 0) {
> - pm_runtime_get_sync(priv->dev);
> -
> ret = rcsi2_start(priv);
> - if (ret) {
> - pm_runtime_put(priv->dev);
> + if (ret)
> goto out;
> - }
> -
> - ret = v4l2_subdev_call(nextsd, video, s_stream, 1);
> - if (ret) {
> - rcsi2_stop(priv);
> - pm_runtime_put(priv->dev);
> - goto out;
> - }
> } else if (!enable && priv->stream_count == 1) {
> rcsi2_stop(priv);
> - v4l2_subdev_call(nextsd, video, s_stream, 0);
> - pm_runtime_put(priv->dev);
> }
>
> priv->stream_count += enable ? 1 : -1;
> @@ -936,6 +947,10 @@ static int rcsi2_probe_resources(struct rcar_csi2 *priv,
> if (irq < 0)
> return irq;
>
> + priv->rstc = devm_reset_control_get(&pdev->dev, NULL);
> + if (IS_ERR(priv->rstc))
> + return PTR_ERR(priv->rstc);
> +
I don't see 'resets' listed as a mandatory property of the rcar-csi2
bindings, shouldn't you fallback to software reset if not 'reset'
is specified? True that all mainline users have a reset property specified,
so you could also add 'resets' among the mandatory properties, could
that break out of tree implementations in your opinion?
Thanks
j
> return 0;
> }
>
> --
> 2.20.1
>
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