media: ti-vpe: cal: fix stop state timeout

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@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
index 3ee1053..4920487 100644 (file)
--- a/drivers/media/platform/ti-vpe/cal.c
+++ b/drivers/media/platform/ti-vpe/cal.c
@@ -6,6 +6,7 @@
  * Benoit Parrot, <bparrot@ti.com>
  */
 
+#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;
@@ -767,6 +769,7 @@ 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
@@ -803,10 +806,20 @@ static void csi2_phy_init(struct cal_ctx *ctx)
        csi2_phy_config(ctx);
 
        /* 3.B. Program Stop States */
+       /*
+        * The stop-state-counter is based on fclk cycles, and we always use
+        * the x16 and x4 settings, so stop-state-timeout =
+        * fclk-cycle * 16 * 4 * counter.
+        *
+        * Stop-state-timeout must be more than 100us as per CSI2 spec, so we
+        * calculate a timeout that's 100us (rounding up).
+        */
+       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,
@@ -2256,6 +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,