Hi Tomi,
Thank you for the patch.
On Fri, Mar 13, 2020 at 01:41:21PM +0200, Tomi Valkeinen wrote:
> The stop-state timeout needs to be over 100us as per CSI spec. With the
> CAL fclk of 266 MHZ on DRA76, with the current value the driver uses,
> the timeout is 24us. Too small timeout will cause failure to enable the
> streaming.
>
> Also, the fclk can be different on other SoCs, as is the case with AM65x
> where the fclk is 250 MHz.
>
> This patch fixes the timeout by calculating it correctly based on the
> fclk rate.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> ---
> drivers/media/platform/ti-vpe/cal.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
> index df5a4281838b..e9dd405b8eb1 100644
> --- a/drivers/media/platform/ti-vpe/cal.c
> +++ b/drivers/media/platform/ti-vpe/cal.c
> @@ -6,6 +6,7 @@
> * Benoit Parrot, <bparrot@xxxxxx>
> */
>
> +#include <linux/clk.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/ioctl.h>
> @@ -340,6 +341,7 @@ static const struct cal_data am654_cal_data = {
> * all instances.
> */
> struct cal_dev {
> + struct clk *fclk;
> int irq;
> void __iomem *base;
> struct resource *res;
> @@ -766,6 +768,7 @@ static void csi2_phy_config(struct cal_ctx *ctx);
> static void csi2_phy_init(struct cal_ctx *ctx)
> {
> u32 val;
> + u32 sscounter;
>
> /* Steps
> * 1. Configure D-PHY mode and enable required lanes
> @@ -802,10 +805,13 @@ static void csi2_phy_init(struct cal_ctx *ctx)
> csi2_phy_config(ctx);
>
> /* 3.B. Program Stop States */
> + /* Must be more than 100us */
You may want to expand this comment to explain the calculation
(especially the * 16 * 4).
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> + sscounter = DIV_ROUND_UP(clk_get_rate(ctx->dev->fclk), 10000 * 16 * 4);
> +
> val = reg_read(ctx->dev, CAL_CSI2_TIMING(ctx->csi2_port));
> set_field(&val, 1, CAL_CSI2_TIMING_STOP_STATE_X16_IO1_MASK);
> - set_field(&val, 0, CAL_CSI2_TIMING_STOP_STATE_X4_IO1_MASK);
> - set_field(&val, 407, CAL_CSI2_TIMING_STOP_STATE_COUNTER_IO1_MASK);
> + set_field(&val, 1, CAL_CSI2_TIMING_STOP_STATE_X4_IO1_MASK);
> + set_field(&val, sscounter, CAL_CSI2_TIMING_STOP_STATE_COUNTER_IO1_MASK);
> reg_write(ctx->dev, CAL_CSI2_TIMING(ctx->csi2_port), val);
> ctx_dbg(3, ctx, "CAL_CSI2_TIMING(%d) = 0x%08x Stop States\n",
> ctx->csi2_port,
> @@ -2263,6 +2269,12 @@ static int cal_probe(struct platform_device *pdev)
> /* save pdev pointer */
> dev->pdev = pdev;
>
> + dev->fclk = devm_clk_get(&pdev->dev, "fck");
> + if (IS_ERR(dev->fclk)) {
> + dev_err(&pdev->dev, "cannot get CAL fclk\n");
> + return PTR_ERR(dev->fclk);
> + }
> +
> syscon_camerrx = syscon_regmap_lookup_by_phandle(parent,
> "ti,camerrx-control");
> ret = of_property_read_u32_index(parent, "ti,camerrx-control", 1,
--
Regards,
Laurent Pinchart
