/************************************************************************
 *　                      I.MX6 ov5640 camera
 * 说明：
 *     记录ov5640摄像头的设备注册方式。
 *
 *                                      2016-6-8 深圳 南山平山村 曾剑锋
 ***********************************************************************/

一、设备注册：
    cat arch/arm/mach-mx6/board-mx6q_sabresd.c
        ......
        static void mx6q_csi0_io_init(void)
        {
            if (cpu_is_mx6q())
                mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_csi0_sensor_pads,
                    ARRAY_SIZE(mx6q_sabresd_csi0_sensor_pads));
            else if (cpu_is_mx6dl())
                mxc_iomux_v3_setup_multiple_pads(mx6dl_sabresd_csi0_sensor_pads,
                    ARRAY_SIZE(mx6dl_sabresd_csi0_sensor_pads));

            /* Camera reset */
            gpio_request(SABRESD_CSI0_RST, "cam-reset");
            gpio_direction_output(SABRESD_CSI0_RST, 1);

            /* Camera power down */
            gpio_request(SABRESD_CSI0_PWN, "cam-pwdn");
            gpio_direction_output(SABRESD_CSI0_PWN, 1);
            msleep(5);
            gpio_set_value(SABRESD_CSI0_PWN, 0);
            msleep(5);
            gpio_set_value(SABRESD_CSI0_RST, 0);
            msleep(1);
            gpio_set_value(SABRESD_CSI0_RST, 1);
            msleep(5);
            gpio_set_value(SABRESD_CSI0_PWN, 1);

            /* For MX6Q:
             * GPR1 bit19 and bit20 meaning:
             * Bit19:       0 - Enable mipi to IPU1 CSI0
             *                      virtual channel is fixed to 0
             *              1 - Enable parallel interface to IPU1 CSI0
             * Bit20:       0 - Enable mipi to IPU2 CSI1
             *                      virtual channel is fixed to 3
             *              1 - Enable parallel interface to IPU2 CSI1
             * IPU1 CSI1 directly connect to mipi csi2,
             *      virtual channel is fixed to 1
             * IPU2 CSI0 directly connect to mipi csi2,
             *      virtual channel is fixed to 2
             *
             * For MX6DL:
             * GPR13 bit 0-2 IPU_CSI0_MUX
             *   000 MIPI_CSI0
             *   100 IPU CSI0
             */
            if (cpu_is_mx6q())
                mxc_iomux_set_gpr_register(1, 19, 1, 1);
            else if (cpu_is_mx6dl())
                mxc_iomux_set_gpr_register(13, 0, 3, 4);
        }
        ......
        static void mx6q_mipi_sensor_io_init(void)
        {
            if (cpu_is_mx6q())
                mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_mipi_sensor_pads,
                    ARRAY_SIZE(mx6q_sabresd_mipi_sensor_pads));
            else if (cpu_is_mx6dl())
                mxc_iomux_v3_setup_multiple_pads(mx6dl_sabresd_mipi_sensor_pads,
                    ARRAY_SIZE(mx6dl_sabresd_mipi_sensor_pads));

            /* Camera reset */
            gpio_request(SABRESD_MIPICSI_RST, "cam-reset");
            gpio_direction_output(SABRESD_MIPICSI_RST, 1);

            /* Camera power down */
            gpio_request(SABRESD_MIPICSI_PWN, "cam-pwdn");
            gpio_direction_output(SABRESD_MIPICSI_PWN, 1);
            msleep(5);
            gpio_set_value(SABRESD_MIPICSI_PWN, 0);
            msleep(5);
            gpio_set_value(SABRESD_MIPICSI_RST, 0);
            msleep(1);
            gpio_set_value(SABRESD_MIPICSI_RST, 1);
            msleep(5);
            gpio_set_value(SABRESD_MIPICSI_PWN, 1);

            /*for mx6dl, mipi virtual channel 1 connect to csi 1*/
            if (cpu_is_mx6dl())
                mxc_iomux_set_gpr_register(13, 3, 3, 1);
        }
        ......
        static struct fsl_mxc_camera_platform_data mipi_csi2_data = {
            .mclk = 24000000,
            .mclk_source = 0,
            .csi = 1,
            .io_init = mx6q_mipi_sensor_io_init,
            .pwdn = mx6q_mipi_powerdown,
        };
        ......
        static struct fsl_mxc_camera_platform_data camera_data = {
            .mclk = 24000000,
            .mclk_source = 0,
            .csi = 0,
            .io_init = mx6q_csi0_io_init,
            .pwdn = mx6q_csi0_cam_powerdown,
        };
        ......
        static struct i2c_board_info mxc_i2c0_board_info[] __initdata = {
            ......
            {
                I2C_BOARD_INFO("ov564x", 0x3c),
                .platform_data = (void *)&camera_data,
            },
            ......
        }
        ......
        static struct i2c_board_info mxc_i2c2_board_info[] __initdata = {
            ......
            {
                I2C_BOARD_INFO("ov5640_mipi", 0x3c),
                .platform_data = (void *)&mipi_csi2_data,
            },
            ......
        }
        ......
            
二、dmesg信息查看：
    root@android:/ # dmesg | grep 5640
    <6>camera ov5640 is found
    <6>camera ov5640_mipi is found
    root@android:/ #