Camera | 12.瑞芯微攝像頭自動焦距馬達(dá)驅(qū)動移植

本為你主要講解如何讓攝像頭ov13850支持自動對焦功能。攝像頭的對角主要通過VCM馬達(dá)驅(qū)動芯片DW9714來實(shí)現(xiàn)的。

一、環(huán)境

soc??:?rk3568???
board:?EVB1-DDR4-V10
軟??件：Android?11
Linux：4.19.232
Camera:ov13850

二、DW9714

1.DW9714簡介

DW9714專為自動對焦和光學(xué)變焦照相手機(jī)、數(shù)碼相機(jī)和攝像機(jī)應(yīng)用而設(shè)計(jì)，

由韓國動運(yùn)國際有限公司（Dongwoon ）設(shè)計(jì)生產(chǎn)。

工作電壓可達(dá)3.6V。

DAC通過I2C串行接口控制，該接口以高達(dá)400kHz的時(shí)鐘速率操作DAC。

DW9714集成了上電復(fù)位電路、掉電功能和精確匹配的檢測電阻。

上電復(fù)位電路確保當(dāng)電源上電時(shí)，DAC輸出為0V，直到發(fā)生有效的寫位值。它具有斷電功能，可將器件的電流消耗降至最大1uA。

2. 特征

用于自動對焦的VCM驅(qū)動程序關(guān)機(jī)功能：XSD=低電平有效VCM的10位分辨率電流吸收為120mAI2C串行接口（可用于1.8V輸入電平）集成電流檢測電阻保證所有代碼的單調(diào)性低至0.5uA（典型值）上電復(fù)位掉電功能2.3V至3.6V操作

3. 模塊圖

4. 引腳

5. 參考電路

6. i2c時(shí)序

由以下時(shí)序可以看到，vcm9714利用I2C接口通信時(shí)，每次讀/寫，直接傳輸2個(gè)字節(jié)的數(shù)據(jù)，通信之前，不需要發(fā)送內(nèi)部寄存器地址。

7. 寄存器格式

三、驅(qū)動移植

vcm9714與rk3568連接圖：

設(shè)備樹：

@arch/arm64/boot/dts/rockchip/rk3568-evb1-ddr4-v10.dtsi
560?????dw9714:?dw9714@c?{
561?????????compatible?=?"dongwoon,dw9714";
562?????????status?=?"okay";
563?????????reg?=?<0x0c>;
564?????????rockchip,camera-module-index?=?<0>;
565?????????rockchip,vcm-start-current?=?<10>;
566?????????rockchip,vcm-rated-current?=?<85>;
567?????????rockchip,vcm-step-mode?=?<5>;
568?????????rockchip,camera-module-facing?=?"back";
569?????};
570?
571?????ov13850:?ov13850@10?{
???……
584?????????lens-focus?=?<&dw9714>;
???……??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
591?????};

其中，下面這兩個(gè)屬性，必須要和對應(yīng)的的攝像頭ov13850信息保持一致

rockchip,camera-module-index?=?<0>;
rockchip,camera-module-facing?=?"back";

攝像頭支持的馬達(dá)驅(qū)動信息通過以下屬性關(guān)聯(lián)

lens-focus?=?<&dw9714>;

Makefile

@kerneldriversmediai2cMakefile
obj-$(CONFIG_VIDEO_DW9714)??+=?dw9714.o

Kconfig

@kerneldriversmediai2cKconfig
config?VIDEO_DW9714
?tristate?"DW9714?lens?voice?coil?support"
?depends?on?I2C?&&?VIDEO_V4L2?&&?MEDIA_CONTROLLER
?depends?on?VIDEO_V4L2_SUBDEV_API
?---help---
???This?is?a?driver?for?the?DW9714?camera?lens?voice?coil.
???DW9714?is?a?10?bit?DAC?with?120mA?output?current?sink
???capability.?This?is?designed?for?linear?control?of
???voice?coil?motors,?controlled?via?I2C?serial?interface.

支持該驅(qū)動：

@?arch/arm64/configs/rockchip_defconfig?
572?CONFIG_VIDEO_DW9714=y??

驅(qū)動：

rk_android11.0_sdk_220718kerneldriversmediai2cdw9714.c

四、調(diào)試信息

1. 啟動的驅(qū)動log

?[????0.800799]?vm149c?4-000c:?probing...
?[????0.800820]?vm149c?4-000c:?driver?version:?00.01.00
?[????0.800834]?vm149c?4-000c:?could?not?get?module?rockchip,vcm-max-current?from?dts!
?[????0.800847]?vm149c?4-000c:?could?not?get?module?rockchip,vcm-start-current?from?dts!
?[????0.800860]?vm149c?4-000c:?could?not?get?module?rockchip,vcm-rated-current?from?dts!
?[????0.800872]?vm149c?4-000c:?could?not?get?module?rockchip,vcm-step-mode?from?dts!
?[????0.800907]?vm149c?4-000c:?probing?successful?

2. 查看拓?fù)浣Y(jié)構(gòu)

media-ctl?-p

……………
?-?entity?74:?m00_b_ov13850?4-0010?(1?pad,?1?link)
?????type?V4L2?subdev?subtype?Sensor
?????device?node?name?/dev/v4l-subdev4
???pad0:?Source
?????[fmt:SBGGR10/4224x3136]
?????->?"rockchip-csi2-dphy0":0?[]

?-?entity?78:?m00_b_gpio-flash?(0?pad,?0?link)
?????type?V4L2?subdev?subtype?Flash
?????device?node?name?/dev/v4l-subdev5

?-?entity?79:?m00_b_dw9714?4-000c?(0?pad,?0?link)
?????type?V4L2?subdev?subtype?Lens
?????device?node?name?/dev/v4l-subdev6

五、驅(qū)動分析

vcm9714驅(qū)動比較簡單，基于i2c總線，

核心就是要注冊基于v4l2的subdev，

提供給用戶層調(diào)用的核心回調(diào)函數(shù)如下：

獲取并設(shè)置當(dāng)前馬達(dá)的pos

static?const?struct?v4l2_ctrl_ops?dw9714_vcm_ctrl_ops?=?{
?.g_volatile_ctrl?=?dw9714_get_ctrl,
?.s_ctrl?=?dw9714_set_ctrl,
};
static?int?dw9714_init_controls(struct?dw9714_device?*dev_vcm)
{
?struct?v4l2_ctrl_handler?*hdl?=?&dev_vcm->ctrls_vcm;
?const?struct?v4l2_ctrl_ops?*ops?=?&dw9714_vcm_ctrl_ops;

?v4l2_ctrl_handler_init(hdl,?1);

?v4l2_ctrl_new_std(hdl,?ops,?V4L2_CID_FOCUS_ABSOLUTE,
?????0,?VCMDRV_MAX_LOG,?1,?VCMDRV_MAX_LOG);
?……
}

static?const?struct?v4l2_subdev_core_ops?dw9714_core_ops?=?{
?.ioctl?=?dw9714_ioctl,
};

static?const?struct?v4l2_subdev_ops?dw9714_ops?=?{
?.core?=?&dw9714_core_ops,
};

static?int?dw9714_probe(struct?i2c_client?*client,
???const?struct?i2c_device_id?*id)
{
?v4l2_i2c_subdev_init(&dw9714_dev->sd,?client,?&dw9714_ops);
}?

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