From 5b6b6be2502fa02b23358658a24bc4e6ad52bf52 Mon Sep 17 00:00:00 2001 From: Naushir Patuck Date: Mon, 11 May 2020 13:02:22 +0100 Subject: [PATCH] media: bcm2835: unicam: Set VPU min clock freq to 250Mhz. When streaming with Unicam, the VPU must have a clock frequency of at least 250Mhz. Otherwise, the input fifos could overrun, causing image corruption. Signed-off-by: Naushir Patuck --- drivers/media/platform/bcm2835/bcm2835-unicam.c | 49 ++++++++++++++++++++++--- 1 file changed, 44 insertions(+), 5 deletions(-) diff --git a/drivers/media/platform/bcm2835/bcm2835-unicam.c b/drivers/media/platform/bcm2835/bcm2835-unicam.c index efa8344..1e9c9f5 100644 --- a/drivers/media/platform/bcm2835/bcm2835-unicam.c +++ b/drivers/media/platform/bcm2835/bcm2835-unicam.c @@ -91,6 +91,11 @@ MODULE_PARM_DESC(debug, "Debug level 0-3"); v4l2_err(&(dev)->v4l2_dev, fmt, ##arg) /* + * Unicam must request a minimum of 250Mhz from the VPU clock. + * Otherwise the input FIFOs overrun and cause image corruption. + */ +#define MIN_VPU_CLOCK_RATE (250 * 1000 * 1000) +/* * To protect against a dodgy sensor driver never returning an error from * enum_mbus_code, set a maximum index value to be used. */ @@ -419,8 +424,10 @@ struct unicam_device { void __iomem *base; /* clock gating base address */ void __iomem *clk_gate_base; - /* clock handle */ + /* lp clock handle */ struct clk *clock; + /* vpu clock handle */ + struct clk *vpu_clock; /* V4l2 device */ struct v4l2_device v4l2_dev; struct media_device mdev; @@ -1680,16 +1687,28 @@ static int unicam_start_streaming(struct vb2_queue *vq, unsigned int count) unicam_dbg(1, dev, "Running with %u data lanes\n", dev->active_data_lanes); - ret = clk_set_rate(dev->clock, 100 * 1000 * 1000); + ret = clk_set_min_rate(dev->vpu_clock, MIN_VPU_CLOCK_RATE); + if (ret) { + unicam_err(dev, "failed to set up VPU clock\n"); + goto err_pm_put; + } + + ret = clk_prepare_enable(dev->vpu_clock); if (ret) { - unicam_err(dev, "failed to set up clock\n"); + unicam_err(dev, "Failed to enable VPU clock: %d\n", ret); goto err_pm_put; } + ret = clk_set_rate(dev->clock, 100 * 1000 * 1000); + if (ret) { + unicam_err(dev, "failed to set up CSI clock\n"); + goto err_vpu_clock; + } + ret = clk_prepare_enable(dev->clock); if (ret) { unicam_err(dev, "Failed to enable CSI clock: %d\n", ret); - goto err_pm_put; + goto err_vpu_clock; } for (i = 0; i < ARRAY_SIZE(dev->node); i++) { @@ -1723,6 +1742,11 @@ static int unicam_start_streaming(struct vb2_queue *vq, unsigned int count) err_disable_unicam: unicam_disable(dev); clk_disable_unprepare(dev->clock); +err_vpu_clock: + ret = clk_set_min_rate(dev->vpu_clock, 0); + if (ret) + unicam_err(dev, "failed to reset the VPU clock\n"); + clk_disable_unprepare(dev->vpu_clock); err_pm_put: unicam_runtime_put(dev); err_streaming: @@ -1740,6 +1764,8 @@ static void unicam_stop_streaming(struct vb2_queue *vq) node->streaming = false; if (node->pad_id == IMAGE_PAD) { + int ret; + /* * Stop streaming the sensor and disable the peripheral. * We cannot continue streaming embedded data with the @@ -1749,6 +1775,12 @@ static void unicam_stop_streaming(struct vb2_queue *vq) unicam_err(dev, "stream off failed in subdev\n"); unicam_disable(dev); + + ret = clk_set_min_rate(dev->vpu_clock, 0); + if (ret) + unicam_err(dev, "failed to reset the min VPU clock\n"); + + clk_disable_unprepare(dev->vpu_clock); clk_disable_unprepare(dev->clock); unicam_runtime_put(dev); @@ -2752,11 +2784,18 @@ static int unicam_probe(struct platform_device *pdev) unicam->clock = devm_clk_get(&pdev->dev, "lp"); if (IS_ERR(unicam->clock)) { - unicam_err(unicam, "Failed to get clock\n"); + unicam_err(unicam, "Failed to get lp clock\n"); ret = PTR_ERR(unicam->clock); goto err_unicam_put; } + unicam->vpu_clock = devm_clk_get(&pdev->dev, "vpu"); + if (IS_ERR(unicam->vpu_clock)) { + unicam_err(unicam, "Failed to get vpu clock\n"); + ret = PTR_ERR(unicam->vpu_clock); + goto err_unicam_put; + } + ret = platform_get_irq(pdev, 0); if (ret <= 0) { dev_err(&pdev->dev, "No IRQ resource\n"); -- 2.7.4