Re: [PATCH v4 23/36] media: imx: Add MIPI CSI-2 Receiver subdev driver
From: Philipp Zabel
Date: Fri Feb 17 2017 - 09:17:46 EST
On Fri, 2017-02-17 at 11:47 +0100, Philipp Zabel wrote:
> On Wed, 2017-02-15 at 18:19 -0800, Steve Longerbeam wrote:
> > 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@xxxxxxxxxx>
> > ---
> > 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
>
> If the table in https://community.nxp.com/docs/DOC-94312 is correct,
> this should be 850 Mbps. Where does this 300 Mbps value come from?
I got it, the dptdin_map value for 300 Mbps is 0x14 in the Rockchip DSI
driver. But that value is written to the register as HSFREQRANGE_SEL(x):
#define HSFREQRANGE_SEL(val) (((val) & 0x3f) << 1)
which is 0x28. Further, the Rockchip D-PHY probably is another version,
as its max_mbps goes up to 1500.
regards
Philipp