[PATCH v4 23/36] media: imx: Add MIPI CSI-2 Receiver subdev driver

Steve Longerbeam
2017-02-16T02:19:25Z

Adds MIPI CSI-2 Receiver subdev driver. This subdev is required
for sensors with a MIPI CSI2 interface.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
---
drivers/staging/media/imx/Makefile | 1 +
drivers/staging/media/imx/imx6-mipi-csi2.c | 573 +++++++++++++++++++++++++++++
2 files changed, 574 insertions(+)
create mode 100644 drivers/staging/media/imx/imx6-mipi-csi2.c

diff --git a/drivers/staging/media/imx/Makefile b/drivers/staging/media/imx/Makefile
index 878a126..3569625 100644
--- a/drivers/staging/media/imx/Makefile
+++ b/drivers/staging/media/imx/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-vdic.o
obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-ic.o

obj-$(CONFIG_VIDEO_IMX_CSI) += imx-media-csi.o
+obj-$(CONFIG_VIDEO_IMX_CSI) += imx6-mipi-csi2.o
diff --git a/drivers/staging/media/imx/imx6-mipi-csi2.c b/drivers/staging/media/imx/imx6-mipi-csi2.c
new file mode 100644
index 0000000..23dca80
--- /dev/null
+++ b/drivers/staging/media/imx/imx6-mipi-csi2.c
@@ -0,0 +1,573 @@
+/*
+ * MIPI CSI-2 Receiver Subdev for Freescale i.MX6 SOC.
+ *
+ * Copyright (c) 2012-2017 Mentor Graphics Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-of.h>
+#include <media/v4l2-subdev.h>
+#include "imx-media.h"
+
+/*
+ * there must be 5 pads: 1 input pad from sensor, and
+ * the 4 virtual channel output pads
+ */
+#define CSI2_SINK_PAD 0
+#define CSI2_NUM_SINK_PADS 1
+#define CSI2_NUM_SRC_PADS 4
+#define CSI2_NUM_PADS 5
+
+struct csi2_dev {
+ struct device *dev;
+ struct v4l2_subdev sd;
+ struct media_pad pad[CSI2_NUM_PADS];
+ struct v4l2_mbus_framefmt format_mbus;
+ struct clk *dphy_clk;
+ struct clk *cfg_clk;
+ struct clk *pix_clk; /* what is this? */
+ void __iomem *base;
+ struct v4l2_of_bus_mipi_csi2 bus;
+ bool on;
+ bool stream_on;
+ bool src_linked;
+ bool sink_linked[CSI2_NUM_SRC_PADS];
+};
+
+#define DEVICE_NAME "imx6-mipi-csi2"
+
+/* Register offsets */
+#define CSI2_VERSION 0x000
+#define CSI2_N_LANES 0x004
+#define CSI2_PHY_SHUTDOWNZ 0x008
+#define CSI2_DPHY_RSTZ 0x00c
+#define CSI2_RESETN 0x010
+#define CSI2_PHY_STATE 0x014
+#define PHY_STOPSTATEDATA_BIT 4
+#define PHY_STOPSTATEDATA(n) BIT(PHY_STOPSTATEDATA_BIT + (n))
+#define PHY_RXCLKACTIVEHS BIT(8)
+#define PHY_RXULPSCLKNOT BIT(9)
+#define PHY_STOPSTATECLK BIT(10)
+#define CSI2_DATA_IDS_1 0x018
+#define CSI2_DATA_IDS_2 0x01c
+#define CSI2_ERR1 0x020
+#define CSI2_ERR2 0x024
+#define CSI2_MSK1 0x028
+#define CSI2_MSK2 0x02c
+#define CSI2_PHY_TST_CTRL0 0x030
+#define PHY_TESTCLR BIT(0)
+#define PHY_TESTCLK BIT(1)
+#define CSI2_PHY_TST_CTRL1 0x034
+#define PHY_TESTEN BIT(16)
+#define CSI2_SFT_RESET 0xf00
+
+static inline struct csi2_dev *sd_to_dev(struct v4l2_subdev *sdev)
+{
+ return container_of(sdev, struct csi2_dev, sd);
+}
+
+static void csi2_enable(struct csi2_dev *csi2, bool enable)
+{
+ if (enable) {
+ writel(0x1, csi2->base + CSI2_PHY_SHUTDOWNZ);
+ writel(0x1, csi2->base + CSI2_DPHY_RSTZ);
+ writel(0x1, csi2->base + CSI2_RESETN);
+ } else {
+ writel(0x0, csi2->base + CSI2_PHY_SHUTDOWNZ);
+ writel(0x0, csi2->base + CSI2_DPHY_RSTZ);
+ writel(0x0, csi2->base + CSI2_RESETN);
+ }
+}
+
+static void csi2_set_lanes(struct csi2_dev *csi2)
+{
+ int lanes = csi2->bus.num_data_lanes;
+
+ writel(lanes - 1, csi2->base + CSI2_N_LANES);
+}
+
+static void dw_mipi_csi2_phy_write(struct csi2_dev *csi2,
+ u32 test_code, u32 test_data)
+{
+ /* Clear PHY test interface */
+ writel(PHY_TESTCLR, csi2->base + CSI2_PHY_TST_CTRL0);
+ writel(0x0, csi2->base + CSI2_PHY_TST_CTRL1);
+ writel(0x0, csi2->base + CSI2_PHY_TST_CTRL0);
+
+ /* Raise test interface strobe signal */
+ writel(PHY_TESTCLK, csi2->base + CSI2_PHY_TST_CTRL0);
+
+ /* Configure address write on falling edge and lower strobe signal */
+ writel(PHY_TESTEN | test_code, csi2->base + CSI2_PHY_TST_CTRL1);
+ writel(0x0, csi2->base + CSI2_PHY_TST_CTRL0);
+
+ /* Configure data write on rising edge and raise strobe signal */
+ writel(test_data, csi2->base + CSI2_PHY_TST_CTRL1);
+ writel(PHY_TESTCLK, csi2->base + CSI2_PHY_TST_CTRL0);
+
+ /* Clear strobe signal */
+ writel(0x0, csi2->base + CSI2_PHY_TST_CTRL0);
+}
+
+static void csi2_dphy_init(struct csi2_dev *csi2)
+{
+ /*
+ * FIXME: 0x14 is derived from a fixed D-PHY reference
+ * clock from the HSI_TX PLL, and a fixed target lane max
+ * bandwidth of 300 Mbps. This value should be derived
+ * from the dphy_clk rate and the desired max lane bandwidth.
+ * See drivers/gpu/drm/rockchip/dw-mipi-dsi.c for more info
+ * on how this value is derived.
+ */
+ dw_mipi_csi2_phy_write(csi2, 0x44, 0x14);
+}
+
+/*
+ * Waits for ultra-low-power state on D-PHY clock lane. This is currently
+ * unused and may not be needed at all, but keep around just in case.
+ */
+static int __maybe_unused csi2_dphy_wait_ulp(struct csi2_dev *csi2)
+{
+ u32 reg;
+ int ret;
+
+ /* wait for ULP on clock lane */
+ ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
+ !(reg & PHY_RXULPSCLKNOT), 0, 500000);
+ if (ret) {
+ v4l2_err(&csi2->sd, "ULP timeout, phy_state = 0x%08x\n", reg);
+ return ret;
+ }
+
+ /* wait until no errors on bus */
+ ret = readl_poll_timeout(csi2->base + CSI2_ERR1, reg,
+ reg == 0x0, 0, 500000);
+ if (ret) {
+ v4l2_err(&csi2->sd, "stable bus timeout, err1 = 0x%08x\n", reg);
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * Waits for low-power LP-11 state (aka STOPSTATE) on data and clock
+ * lanes.
+ */
+static int csi2_dphy_wait_stopstate(struct csi2_dev *csi2)
+{
+ u32 mask, reg;
+ int ret;
+
+ mask = PHY_STOPSTATECLK |
+ ((csi2->bus.num_data_lanes - 1) << PHY_STOPSTATEDATA_BIT);
+
+ ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
+ (reg & mask) == mask, 0, 500000);
+ if (ret) {
+ v4l2_err(&csi2->sd, "LP-11 timeout, phy_state = 0x%08x\n", reg);
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * Wait for active clock on the clock lane.
+ *
+ * FIXME: Currently unused, but it should be! It should be called
+ * from csi2_s_stream() below, at stream ON, but the required sequence
+ * of MIPI CSI-2 startup does not allow for an opportunity for this to
+ * be called. The sequence as specified in the i.MX6 reference manual
+ * is as follows:
+ *
+ * 1. Deassert presetn signal (global reset).
+ * It's not clear what this "global reset" signal is (maybe APB
+ * global reset), but in any case this step corresponds to
+ * csi2_s_power(ON) here.
+ *
+ * 2. Configure MIPI Camera Sensor to put all Tx lanes in PL-11 state.
+ * This must be carried out by the MIPI sensor's s_power(ON) subdev
+ * op.
+ *
+ * 3. D-PHY initialization.
+ * 4. CSI2 Controller programming (Set N_LANES, deassert PHY_SHUTDOWNZ,
+ * deassert PHY_RSTZ, deassert CSI2_RESETN).
+ * 5. Read the PHY status register (PHY_STATE) to confirm that all data and
+ * clock lanes of the D-PHY are in Stop State.
+ * These steps (3,4,5) are carried out by csi2_s_stream(ON) here.
+ *
+ * 6. Configure the MIPI Camera Sensor to start transmitting a clock on the
+ * D-PHY clock lane.
+ * This must be carried out by the MIPI sensor's s_stream(ON) subdev
+ * op.
+ *
+ * 7. CSI2 Controller programming - Read the PHY status register (PHY_STATE)
+ * to confirm that the D-PHY is receiving a clock on the D-PHY clock lane.
+ * This is implemented by this unused function, and _should_ be called
+ * by csi2_s_stream(ON) here, but csi2_s_stream(ON) has been taken up
+ * by steps 3,4,5 above already.
+ *
+ * In summary, a temporary solution would require a hard-coded delay in the
+ * MIPI sensor's s_stream(ON) op, to allow time for a stable clock lane.
+ *
+ * A longer term solution might be to create a new subdev op, perhaps
+ * called prepare_stream, that can be implemented here, and would be
+ * assigned steps 3,4,5. Then csi2_s_stream(ON) would become available
+ * as step 7.
+ */
+static int __maybe_unused csi2_dphy_wait_clock_lane(struct csi2_dev *csi2)
+{
+ u32 reg;
+ int ret;
+
+ ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
+ (reg & PHY_RXCLKACTIVEHS), 0, 500000);
+ if (ret) {
+ v4l2_err(&csi2->sd, "clock lane timeout, phy_state = 0x%08x\n",
+ reg);
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * V4L2 subdev operations.
+ */
+
+/* Startup Sequence Step 1 */
+static int csi2_s_power(struct v4l2_subdev *sd, int on)
+{
+ struct csi2_dev *csi2 = sd_to_dev(sd);
+ int ret;
+
+ if (on && !csi2->on) {
+ dev_dbg(csi2->dev, "power ON\n");
+ ret = clk_prepare_enable(csi2->cfg_clk);
+ if (ret)
+ return ret;
+ ret = clk_prepare_enable(csi2->dphy_clk);
+ if (ret)
+ goto cfg_clk_off;
+ } else if (!on && csi2->on) {
+ dev_dbg(csi2->dev, "power OFF\n");
+ clk_disable_unprepare(csi2->dphy_clk);
+ clk_disable_unprepare(csi2->cfg_clk);
+ }
+
+ csi2->on = on;
+
+ return 0;
+
+cfg_clk_off:
+ clk_disable_unprepare(csi2->cfg_clk);
+ return ret;
+}
+
+/* Startup Sequence Steps 3, 4, 5 */
+static int csi2_s_stream(struct v4l2_subdev *sd, int enable)
+{
+ struct csi2_dev *csi2 = sd_to_dev(sd);
+ int i, ret = 0;
+
+ if (!csi2->src_linked)
+ return -EPIPE;
+ for (i = 0; i < CSI2_NUM_SRC_PADS; i++) {
+ if (csi2->sink_linked[i])
+ break;
+ }
+ if (i >= CSI2_NUM_SRC_PADS)
+ return -EPIPE;
+
+ if (enable && !csi2->stream_on) {
+ dev_dbg(csi2->dev, "stream ON\n");
+
+ ret = clk_prepare_enable(csi2->pix_clk);
+ if (ret)
+ return ret;
+
+ /* Step 3 */
+ csi2_dphy_init(csi2);
+ /* Step 4 */
+ csi2_set_lanes(csi2);
+ csi2_enable(csi2, true);
+
+ /* Step 5 */
+ ret = csi2_dphy_wait_stopstate(csi2);
+ if (ret) {
+ csi2_enable(csi2, false);
+ clk_disable_unprepare(csi2->pix_clk);
+ return ret;
+ }
+ } else if (!enable && csi2->stream_on) {
+ dev_dbg(csi2->dev, "stream OFF\n");
+ csi2_enable(csi2, false);
+ clk_disable_unprepare(csi2->pix_clk);
+ }
+
+ csi2->stream_on = enable;
+ return 0;
+}
+
+static int csi2_link_setup(struct media_entity *entity,
+ const struct media_pad *local,
+ const struct media_pad *remote, u32 flags)
+{
+ struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
+ struct csi2_dev *csi2 = sd_to_dev(sd);
+ struct v4l2_subdev *remote_sd;
+
+ dev_dbg(csi2->dev, "link setup %s -> %s", remote->entity->name,
+ local->entity->name);
+
+ remote_sd = media_entity_to_v4l2_subdev(remote->entity);
+
+ if (local->flags & MEDIA_PAD_FL_SOURCE) {
+ if (flags & MEDIA_LNK_FL_ENABLED) {
+ if (csi2->sink_linked[local->index])
+ return -EBUSY;
+ csi2->sink_linked[local->index] = true;
+ } else {
+ csi2->sink_linked[local->index] = false;
+ }
+ } else {
+ if (flags & MEDIA_LNK_FL_ENABLED) {
+ if (csi2->src_linked)
+ return -EBUSY;
+ csi2->src_linked = true;
+ } else {
+ csi2->src_linked = false;
+ }
+ }
+
+ return 0;
+}
+
+static int csi2_get_fmt(struct v4l2_subdev *sd,
+ struct v4l2_subdev_pad_config *cfg,
+ struct v4l2_subdev_format *sdformat)
+{
+ struct csi2_dev *csi2 = sd_to_dev(sd);
+ struct v4l2_mbus_framefmt *fmt;
+
+ if (sdformat->which == V4L2_SUBDEV_FORMAT_TRY)
+ fmt = v4l2_subdev_get_try_format(&csi2->sd, cfg,
+ sdformat->pad);
+ else
+ fmt = &csi2->format_mbus;
+
+ sdformat->format = *fmt;
+
+ return 0;
+}
+
+static int csi2_set_fmt(struct v4l2_subdev *sd,
+ struct v4l2_subdev_pad_config *cfg,
+ struct v4l2_subdev_format *sdformat)
+{
+ struct csi2_dev *csi2 = sd_to_dev(sd);
+
+ if (sdformat->pad >= CSI2_NUM_PADS)
+ return -EINVAL;
+
+ if (csi2->stream_on)
+ return -EBUSY;
+
+ /* Output pads mirror active input pad, no limits on input pads */
+ if (sdformat->pad != CSI2_SINK_PAD)
+ sdformat->format = csi2->format_mbus;
+
+ if (sdformat->which == V4L2_SUBDEV_FORMAT_TRY)
+ cfg->try_fmt = sdformat->format;
+ else
+ csi2->format_mbus = sdformat->format;
+
+ return 0;
+}
+
+/*
+ * retrieve our pads parsed from the OF graph by the media device
+ */
+static int csi2_registered(struct v4l2_subdev *sd)
+{
+ struct csi2_dev *csi2 = sd_to_dev(sd);
+ int i, ret;
+
+ for (i = 0; i < CSI2_NUM_PADS; i++) {
+ csi2->pad[i].flags = (i == CSI2_SINK_PAD) ?
+ MEDIA_PAD_FL_SINK : MEDIA_PAD_FL_SOURCE;
+ }
+
+ /* set a default mbus format */
+ ret = imx_media_init_mbus_fmt(&csi2->format_mbus,
+ 640, 480, 0, V4L2_FIELD_NONE, NULL);
+ if (ret)
+ return ret;
+
+ return media_entity_pads_init(&sd->entity, CSI2_NUM_PADS, csi2->pad);
+}
+
+static struct media_entity_operations csi2_entity_ops = {
+ .link_setup = csi2_link_setup,
+ .link_validate = v4l2_subdev_link_validate,
+};
+
+static struct v4l2_subdev_core_ops csi2_core_ops = {
+ .s_power = csi2_s_power,
+};
+
+static struct v4l2_subdev_video_ops csi2_video_ops = {
+ .s_stream = csi2_s_stream,
+};
+
+static struct v4l2_subdev_pad_ops csi2_pad_ops = {
+ .get_fmt = csi2_get_fmt,
+ .set_fmt = csi2_set_fmt,
+};
+
+static struct v4l2_subdev_ops csi2_subdev_ops = {
+ .core = &csi2_core_ops,
+ .video = &csi2_video_ops,
+ .pad = &csi2_pad_ops,
+};
+
+static struct v4l2_subdev_internal_ops csi2_internal_ops = {
+ .registered = csi2_registered,
+};
+
+static int csi2_parse_endpoints(struct csi2_dev *csi2)
+{
+ struct device_node *node = csi2->dev->of_node;
+ struct device_node *epnode;
+ struct v4l2_of_endpoint ep;
+
+ epnode = of_graph_get_endpoint_by_regs(node, 0, -1);
+ if (!epnode) {
+ v4l2_err(&csi2->sd, "failed to get sink endpoint node\n");
+ return -EINVAL;
+ }
+
+ v4l2_of_parse_endpoint(epnode, &ep);
+ of_node_put(epnode);
+
+ if (ep.bus_type != V4L2_MBUS_CSI2) {
+ v4l2_err(&csi2->sd, "invalid bus type, must be MIPI CSI2\n");
+ return -EINVAL;
+ }
+
+ csi2->bus = ep.bus.mipi_csi2;
+
+ dev_dbg(csi2->dev, "data lanes: %d\n", csi2->bus.num_data_lanes);
+ dev_dbg(csi2->dev, "flags: 0x%08x\n", csi2->bus.flags);
+ return 0;
+}
+
+static int csi2_probe(struct platform_device *pdev)
+{
+ struct csi2_dev *csi2;
+ struct resource *res;
+ int ret;
+
+ csi2 = devm_kzalloc(&pdev->dev, sizeof(*csi2), GFP_KERNEL);
+ if (!csi2)
+ return -ENOMEM;
+
+ csi2->dev = &pdev->dev;
+
+ v4l2_subdev_init(&csi2->sd, &csi2_subdev_ops);
+ v4l2_set_subdevdata(&csi2->sd, &pdev->dev);
+ csi2->sd.internal_ops = &csi2_internal_ops;
+ csi2->sd.entity.ops = &csi2_entity_ops;
+ csi2->sd.dev = &pdev->dev;
+ csi2->sd.owner = THIS_MODULE;
+ csi2->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
+ strcpy(csi2->sd.name, DEVICE_NAME);
+ csi2->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+ csi2->sd.grp_id = IMX_MEDIA_GRP_ID_CSI2;
+
+ ret = csi2_parse_endpoints(csi2);
+ if (ret)
+ return ret;
+
+ csi2->cfg_clk = devm_clk_get(&pdev->dev, "cfg");
+ if (IS_ERR(csi2->cfg_clk)) {
+ v4l2_err(&csi2->sd, "failed to get cfg clock\n");
+ ret = PTR_ERR(csi2->cfg_clk);
+ return ret;
+ }
+
+ csi2->dphy_clk = devm_clk_get(&pdev->dev, "dphy");
+ if (IS_ERR(csi2->dphy_clk)) {
+ v4l2_err(&csi2->sd, "failed to get dphy clock\n");
+ ret = PTR_ERR(csi2->dphy_clk);
+ return ret;
+ }
+
+ csi2->pix_clk = devm_clk_get(&pdev->dev, "pix");
+ if (IS_ERR(csi2->pix_clk)) {
+ v4l2_err(&csi2->sd, "failed to get pixel clock\n");
+ ret = PTR_ERR(csi2->pix_clk);
+ return ret;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ v4l2_err(&csi2->sd, "failed to get platform resources\n");
+ return -ENODEV;
+ }
+
+ csi2->base = devm_ioremap(&pdev->dev, res->start, PAGE_SIZE);
+ if (!csi2->base) {
+ v4l2_err(&csi2->sd, "failed to map CSI-2 registers\n");
+ return -ENOMEM;
+ }
+
+ platform_set_drvdata(pdev, &csi2->sd);
+
+ return v4l2_async_register_subdev(&csi2->sd);
+}
+
+static int csi2_remove(struct platform_device *pdev)
+{
+ struct v4l2_subdev *sd = platform_get_drvdata(pdev);
+
+ csi2_s_power(sd, 0);
+
+ v4l2_async_unregister_subdev(sd);
+ media_entity_cleanup(&sd->entity);
+
+ return 0;
+}
+
+static const struct of_device_id csi2_dt_ids[] = {
+ { .compatible = "fsl,imx6-mipi-csi2", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, csi2_dt_ids);
+
+static struct platform_driver csi2_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = csi2_dt_ids,
+ },
+ .probe = csi2_probe,
+ .remove = csi2_remove,
+};
+
+module_platform_driver(csi2_driver);
+
+MODULE_DESCRIPTION("i.MX5/6 MIPI CSI-2 Receiver driver");
+MODULE_AUTHOR("Steve Longerbeam <steve_longerbeam@mentor.com>");
+MODULE_LICENSE("GPL");
--
2.7.4