STM32MP157 Linux系统移植开发篇17：Linux内核摄像头驱动移植

STMCU小助手 · 2022-09-29T10:36:04+00:00

1.实验原理 4 P# X; O' l2 Q+ D# W" o" M8 DDCMI(Digital Camera Interface)，DCMI是一个同步并行接口，能够从外部8bit、10bit、12bit或14bit的CMOS摄像头接收高速数据流，支持不同的数据格式：YCbCr4:2:2/RGB565渐进式视频和压缩数据（JPEG）。 % p p6 c+ [1 q, v0 N% ?( M' F3 W8 x' |2 {/ A- G 5 d: T: Z: q( G7 k 5 M { e& l3 O+ F3 U9 u, YFS-MP1A可以外接8bit的COM Camera，接口定义如下:& |& F: U$ b' h4 ^+ ] . B3 ?) B1 }; } W " Q o. \9 Q9 W/ B/ U9 O4 n3 w$ d0 ? . Z# `9 f1 {$ T U接口与MPU管脚对应关系如下： & `% x* @" Y* m4 j 0 t& h0 i3 f. k1 F0 @* G 4 ~! ~; l6 g* v2 R: E6 Z 1 j4 B1 V+ _' B0 d! ]( Y- j a. }* D/ e0 `7 ^% \; E# c 1 Z8 P. B! ] N1 \2 Z& z7 h1 }0 g. y 0 l0 @( J# t. t/ {- t0 H : e. Y1 q: x3 ]- U0 d& N 9 e( c2 K3 Q" x 5 i i% D. U3 t9 i3 G) ^ @( i" v* }; E3 \ - j1 H& Y; H5 n! X/ O( L8 d' s + C1 V5 P7 S0 K0 t ; i) N/ B @+ y, O" Y3 z 内核中ST对STM32MP15x系列芯片的设备树资源了做了定义，可参见：" I$ P5 ^2 t: L8 o5 N! q- H5 W ' t6 M" `% D3 ~: i. Varch/arm/boot/dts/stm32mp151.dtsi , m4 ]5 f6 V; I/ p u+ x' @( b% q( s2 Y; x7 G: H stm32mp151中dcmi定义如下：4 z( b+ p8 l0 m4 V 5 K1 u, i) a: w. F dcmi: dcmi@4c006000 { 1 m$ n" R, F' {- W0 u% _& ~2 v; K B8 l9 Y compatible = "st,stm32-dcmi"; 6 v$ S4 w1 Q; u( E8 V( D0 ?6 ~2 y% ^2 ~0 a! g3 R reg = ;1 k* g# A/ q/ J ( p9 O5 Z1 D+ S# V interrupts = ;1 R3 y1 o1 w" E `3 }( r 5 ^8 m( y r/ c, F resets = ; & y ]- C, j8 O, y) y ' N% r1 \: p/ o; ?8 Eclocks = ; 7 R3 F7 T" y: Z0 K. p+ @, F! D! e9 R2 y4 t4 w3 e: }( L- G clock-names = "mclk";6 X0 Y, }2 A6 @) ~ $ h/ U# a8 ]" i2 L' Qdmas = ; " q ^5 P+ M- A" H6 X6 ]4 V' i0 R! B6 |' b) W) j6 H/ L dma-names = "tx"; $ a3 @( i1 a7 E& a2 f0 W # d9 ]- t- W' Sstatus = "disabled"; ~8 ?+ f' J3 g% ~$ D5 v- m" f6 I9 |6 B/ J- N }; : {2 J) c$ J: T ( V# `9 _9 f# _- V. c1 x- ?$ x上述代码只对dcmi做了基本的初始化，并没有针对不同的硬件设计做适配，所以需结合硬件补全设备树节点信息。: [8 ^& d9 }! f; b1 r1 Q% { " v9 v% o5 K* d) W8 C3 Y 参考帮助文档及内核中其它STM32MP157设备树中对于dcmi的定义，修改dcmi内容如下：7 R! G8 @5 o/ Y8 M1 r- O 8 _, d" Y8 v( a1 y &dcmi {1 T8 ?. Z" _( D7 x1 s , Y7 I- a1 ~0 e" l. i1 Fstatus = "okay";2 @% w( Z9 }1 \& C/ n X * F/ G4 s; o* J. T% F" ]8 }; [2 _5 I" b: A" npinctrl-names = "default", "sleep"; $ X* p2 Q$ }1 Q' O$ R: ]2 r # x& [) }1 U4 X: v& B3 v* n Xpinctrl-0 = ; 4 U! y: X/ R O. m; v) P/ k5 \9 A7 n" A, d/ X; A. e/ L pinctrl-1 = ; ) N: Z4 i/ {; T. O5 I- z9 D1 E* r$ S/ | port { # W) l- b$ ? D8 z5 i 6 U8 A# g H3 m! sdcmi_0: endpoint {* C ^( `5 P! P) e/ f& l0 Y5 N1 L & o' Z5 ?5 J' u* ^5 nremote-endpoint = ; 6 d8 o2 \3 @. B6 ]# R+ p / D! I, Y+ P) Ubus-width = ; 5 \7 e7 z5 N' e$ Q4 S. \3 w. M6 S hsync-active = ;) l9 C& f/ u( v S N/ L 7 p+ `' P; @, h! g- Avsync-active = ; % w K. J1 B! B* M- W' a/ r- U* d" U {6 _ pclk-sample = ;; u4 y6 }8 m4 }7 [$ k3 i( G+ s ' V2 T0 U/ r i- ^, m' g7 c pclk-max-frequency = ; $ z& L/ j" B1 u. W$ R 3 I, }/ k* x/ K+ B}; ) o2 s' i" K. a' e( k3 R* h" u+ b };" ]9 v. ^3 `3 `- H+ G) R 8 [& h) H f/ Z% |% k( M };7 ?% o; Y% V2 F* q ' h6 H, i3 N$ J R; _由于stm32mp15-pinctrl.dtsi中对于DCMI管脚的定义与FS-MP1A实际使用管脚一致，所以无需修改$ M; w1 \) j* p( l5 n: X- D7 v ' j+ I7 m1 C" ]: \1.CMOS Camera设备树节点( u: j' b$ K" j1 m1 b" ` FS-MP1A支持多款COMS Camera，本节以ov5640为例： # |2 t, L7 E: `2 S0 R5 t* ], f & w2 d: Z' `- f5 W) C$ o参考帮助文档及内核中其它STM32MP157设备树中对于ov5640的定义，修改dcmi内容如下：9 d. A, s# M* h. [ 2 ~* `9 m0 B# K1 ?2 G- l2 b% J( Eov5640: camera@3c { 0 e l% d" Z) |7 d0 m" Y0 g% d5 |9 _8 I. u4 e) I0 T$ B3 l compatible = "ovti,ov5640"; 0 C9 e; s9 y" V! r, K; `; A e: p% s" f* ~; @" l6 Z! X reg = ; / _. U, x# g3 E$ A5 e # d1 r9 K! h. ]. f4 aclocks = ;3 U. w6 c" r! D3 F5 g; h ' `9 D# S! |3 C& w0 t w5 rclock-names = "xclk"; 1 ?& L/ |) t0 J6 z $ k7 i# B3 [. `' |& t- O3 m2 tDOVDD-supply = ; . p7 _9 M8 K2 j2 B& _5 V( s" z" ]9 i( `9 I powerdown-gpios = ; & L; K9 E: F& s# d- i& H' z4 p , `3 m, D+ B1 M/ }1 `reset-gpios = ;6 ]$ W2 ]$ e. J/ Q1 ]* m K 8 K5 s2 B5 O5 w* n. S9 l# wrotation = ;3 L, ?; p: | j ' ?: \, s( x: i6 k' s* ?1 e. Astatus = "okay";+ G& S; y/ o5 f' G, R ( \! s, P& S! ` port {( Q7 ?+ o2 a- u4 S( q) F+ Y. }" `2 H ' q( H1 i3 C1 V- kov5640_0: endpoint {4 e* B. D3 R6 B: i* m9 m + x: M- w/ v% cremote-endpoint = ; ' O! l# P, M' A7 F4 B: i6 m % a* U# Z- h& ~1 q. s1 gbus-width = ;$ S0 n+ p% i! D! o1 W 2 Y2 F. Z' ~! J5 L7 L; F data-shift = ; /* lines 9:2 are used */! U% c' T, Q! z( \. v - X4 b; t, I$ W. W1 f' qhsync-active = ;# ]8 ]! Y% @' x* {/ @# ?7 ] 0 N! \/ L0 X* `' u5 O, W vsync-active = ; 2 s3 T/ k6 Y8 N: i 6 C* z8 a% T& y3 Jpclk-sample = ; & A/ q. S w4 @4 x4 E6 j8 J+ r7 _9 b- ^5 E/ t" V6 w pclk-max-frequency = ;5 o) U+ Y. s5 w) l' ~$ } ) s& |$ |7 [- J0 I5 K% X/ {' c0 m };$ d9 Y3 O. I0 P6 G6 I+ Y 5 B, m, H3 k& u' m) B7 w }; # S: N4 `9 S1 w: A5 L; H0 h " l. x( H- P$ b5 f- e0 S @- X};0 }1 E' w6 i6 W0 A6 R; p - w' j* v7 g- A8 i+ U6 ^1 |2.2.8V电源定义0 J% l) C: G$ |' f0 ~ 前文已经说过如何添加电源节点，本节不再重复，在根节点添加&v2v8节点，内容如下：, g! s( ~& i" L 1 C! _/ |3 l5 r6 J. B9 @6 @v2v8_audio: regulator-v2v8 {' D* {2 @& ^& U6 p O, H! i; u5 } ! J3 X. x# K' f% l0 ~3 bcompatible = "regulator-fixed";- G: p3 _- E$ {. m " t c# T: Y8 f: wregulator-name = "v2v8";! v( W! _( F6 s0 c+ @- L# s2 {: p+ ` 9 n# @) k$ l. k( x8 F qregulator-min-microvolt = ;/ \* Q* R9 j) F2 B4 \1 X 1 ^: B: {' d9 l$ y regulator-max-microvolt = ;! q1 {" R- f6 c# `- ?( G5 A' Z 6 s3 N- w& p- X$ C6 {regulator-always-on; 6 M2 y2 p# e0 s: f" t& R; k) a& b2 J+ s regulator-boot-on; 0 y7 C8 V$ w" u. s 1 K6 n9 U7 ]+ U% z `8 f2 w) w};, M8 a- m* p7 Z. P) H 4 d$ h( E+ {( ^" Z# {% q 3.24M时钟定义 l& Z2 C+ ?/ d, L0 S 参考文档：0 Q5 ?7 k. w% T! J; J - j, ~( P' U+ L3 D) o& K Documentation/devicetree/bindings/clock/fixed-clock.yaml r* j$ p" C! q6 h# k 9 u9 Z5 F9 D9 f7 `( u 参考帮助文档或内核中其他设备树文件，对于时钟的定义，增加内容如下： 5 _' j2 }5 D% H7 d7 Q8 N1 \ 4 V( {5 b0 N" f! u* m {) Q0 nclocks {: b4 E& J8 K0 }$ \0 C) B3 y$ P . i( a3 s. p9 p7 ]- _3 bclk_ext_camera: clk-ext-camera { : G; Y: p1 H3 d1 X9 w- r: e 7 C% l7 |" c4 N3 p6 x" H- E#clock-cells = ; : p5 v0 v* K" L% d/ h# g( R/ ]/ Y' i* p1 u( d I compatible = "fixed-clock";: W& A2 n# _$ X- K ' W. I( }5 X+ U+ Fclock-frequency = ;2 l- V- |1 X4 v" \6 O6 h+ R ] ( R$ Z9 K3 p3 R! d9 w: F }; " W1 ]$ N: Q* W, T1 } c3 c; \: F; r, S5 R}; 1 v: t& \5 w8 K; z8 A* l$ F, M7 t- e1 c2 e 2.实验目的# t4 s* T% }- U' ^ 熟悉基于Linux操作系统下的摄像头设备驱动移植配置过程。 4 T6 y( r' x6 j, A% {* b3 {& F ) R$ M) D' E+ j- H8 v3.实验平台 ; g7 Y2 q3 T8 z5 Z' F$ ]2 R华清远见开发环境，FS-MP1A平台；) _' k. h: T% D+ I, l! E ) K! G: n# P6 \3 e# A( m: Q2 y# E, V 4.实验步骤% M' W" O5 I; X. H; T" L 导入交叉编译工具链+ t0 j$ Z5 a' g7 L3 I7 y; F) v- Z linux@ubuntu source /opt/st/stm32mp1/3.1-openstlinux-5.4-dunfell-mp1-20-06-24/environment-setup-cortexa7t2hf-neon-vfpv4-ostl-linux-gnueabi) ^8 U- F3 f" l# U0 k0 U" O; [6 g + W4 R8 Y9 D4 j2 x" J+ Z! e3 j 1.增加DCMI设备树节点 9 O W% `: O# {修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件，在文件末尾添加如下内容：# h3 ~ S4 ~8 l. ?* J, ^+ N; k" D 0 j. T2 i x, b; s( N- o' y3 B1 V&dcmi { - ?3 V- X/ } x4 }5 f! m5 L; X* d" [' z4 n6 w6 f& U status = "okay"; 3 r k* z0 z$ G& s" Q4 t & i4 F( g; n8 H* F# B% Cpinctrl-names = "default", "sleep"; + N8 @ C5 `& d6 E& H; V$ D# j. X; A4 | pinctrl-0 = ;2 w+ v: I" \ [/ H9 k! d # s# B" N& v! F4 B) xpinctrl-1 = ; 9 U$ z* @; ^" T* r r8 r# T) Y/ V: N0 O/ y: j% A2 e port { - L) z, [+ i+ F. u" a$ I+ D & |% o. r- h5 t' {# r5 xdcmi_0: endpoint { : G5 \$ d' P) V+ [% l' Z 5 [) B/ C% H% U& h( k8 T2 Lremote-endpoint = ;8 z5 \! u- _/ ] ( |5 E/ E9 s+ x bus-width = ;7 L7 W+ e# D( P f% `- W7 U" e2 i& t hsync-active = ;, O7 W/ ]% U* Z: u1 x `# h( o" l4 F# ~ 8 H$ [. }0 t, { p- ~" u: n: M' cvsync-active = ;; L9 V5 d0 o- ]8 M * V. H. \+ g6 G! l2 ]* D" j pclk-sample = ; 3 G9 x5 c a, T) l8 x" G4 k1 _ ( a, @8 N1 q" `pclk-max-frequency = ;. y; e0 D: i/ U9 P4 ^* _ 9 p$ N% \( t* O5 C };# i, `# @, p5 g6 P! m- E* l0 `: q% Q + ]- _2 ]" A' y3 _4 ]2 u, p/ k};4 v* A, T" W. S# H0 D( z- y7 G: g ~- h; e% R/ t};) b0 [9 m1 ~5 i& v0 w# S* O2 p 5 p! J4 e9 Y1 z( c4 N1 n% E2.增加OV5640节点 . [( @4 ]7 [# Q. d+ j3 D3 s修改arch/arm/dts/stm32mp15xx-fsmp1x.dtsi文件，在I2C5节点中添加OV5640设备信息，红色字体为增加内容： 4 A4 R9 [8 ^) d( S1 r5 z 2 k4 S. w7 F1 M1 x; y&i2c5 {* A9 Y# Y* ]; G' M( S; ? 6 B4 s9 Y( a: _8 Y9 ?- ^9 ]3 Spinctrl-names = "default", "sleep"; . i3 n, t. b, W) _& E: l5 @6 i& b" }% r* k( s! R+ K& ^ pinctrl-0 = ;0 {/ F- T( R& o/ C3 r0 M9 c7 x * i+ P/ M: x% ]/ r…… 4 @; T. O0 _$ c6 q- Z N# T8 k- I& @ E* U ov5640: camera@3c { 8 |1 o' A1 d& t4 d4 y6 }- P% e % T/ W- X& K% S# M" s, ]3 p( R5 jcompatible = "ovti,ov5640"; ) K$ g3 R1 d& x1 W; P5 B$ B+ h % z& D g5 o- B2 P3 Hreg = ; N5 [6 u' i9 |2 k( B- D : t4 g4 |7 v8 U' \* tclocks = ; 0 i$ A) A$ U+ e! F1 z" g# G4 b2 m }! ^) D clock-names = "xclk"; + A& j' A V; ^- g+ G- o X& ~8 q# a, n# f/ n DOVDD-supply = ;( Y2 i; T- @6 Q9 G # G9 r0 U: J" N# Cpowerdown-gpios = ; , x/ r2 {- K9 G9 p. B1 S y4 A/ y$ s2 i% X reset-gpios = ;: H% `) R/ N" I9 Y5 h$ A2 A, b 8 m! P) o$ e' l/ g: H, z* ^2 B9 Xrotation = ; ( g0 V4 e6 o" z& Q& t* H2 x& P6 m2 b0 P) ]; s! X status = "okay";9 u M$ `: W- n1 g . F4 ^! S; W( ^& s2 n, lport {) F0 l/ g+ ~( ]$ z" ^6 I; W 5 ^( D. x& { |; uov5640_0: endpoint { 2 |" s8 I2 J7 {6 ?8 I* q- N! f: P1 y* x7 W- ?. j- V- j remote-endpoint = ; 1 B b% \# r3 M7 R s0 I7 m * n7 N3 l" ?: i% ^! ]/ gbus-width = ;" [* z7 u4 L4 y # `9 M( Y+ P7 f+ Sdata-shift = ; /* lines 9:2 are used */ 8 L: `0 L) V3 D ( t @$ g; j* ahsync-active = ; 1 d# @9 [5 S& x9 |. u1 L; B0 q. ~3 y1 e) X6 o vsync-active = ;5 |0 }3 ?: D5 Z$ `% u+ z! P' W ' }" @7 Q! W$ z6 W pclk-sample = ;6 F6 _ w, V1 i2 R1 X 2 |; o: p/ H" Npclk-max-frequency = ;6 N5 T) r4 ~0 F8 d; y9 v 4 T$ d3 [6 S3 s3 D4 T/ q) H }; $ B: T7 ]' y! \8 q4 G6 p! u( p 3 u( ~/ N* X! U+ ?- H0 j};( s! |5 O) Z8 C" D" k- | + g6 ?# l7 @) w/ O* N};, Q7 K. [5 f7 h j# _. I , l& K3 _" E+ E# @; l# U }; , q6 _) Z4 @8 i4 t X" l& f+ L/ l J6 R( g* ~* F. D9 { B) q9 p 3.增加2.8V电源和24M时钟 ; K& R5 z9 w2 I( _修改arch/arm/dts/stm32mp15xx-fsmp1x.dtsi文件，在根节点最后添加2.8V电源和24M时钟，红色字体为增加内容：# X9 l! `2 k& h% P' u$ N/ K9 @' ? 9 V% _& a; m0 R7 K' [' @) t, M Q! l. Y / { 7 |7 p: Y+ h; t4 @2 s; `# l ) B3 O: N/ W( Wmemory@c0000000 { ' A. T+ D+ \% w. E6 o8 I5 ^& o, S 7 s* j0 @, t& y. Gdevice_type = "memory"; 5 l' b# {% Q: l1 Q$ N$ s1 y$ w* j# q2 I reg = ;: G# d2 S' O; g+ z; S$ _ + U. i' |0 t: f4 E2 X. k9 ~ }; ) |. X6 @) o" G ; U, _! y T3 @……- V) h& N1 K( X/ g 3 m: H0 V, q9 B+ v+ H1 G v2v8: regulator-2p8v {' j, h- g/ E4 ~! L5 @, w5 Q) o' Y * v, f! D$ `* [, y compatible = "regulator-fixed"; / ~) |, A! i" V6 Z- O; o 9 u: M5 G, @/ d" c3 M. `9 Hregulator-name = "v2v8"; h4 t$ B' `. G+ Y8 d. N4 \9 E) J5 _( Q% T# }4 A8 J. d regulator-min-microvolt = ;" l0 _& ]. _$ R/ x4 H ' O0 n0 r; a e, yregulator-max-microvolt = ; ! Q9 i) V3 Q) D7 I1 P( x- O- {. B5 n) S% C# U8 L3 w% N regulator-always-on; $ C. \* R3 w# w" S% U . \. L8 O7 S0 S8 S: x0 m/ Q4 gregulator-boot-on; 0 u" H! R. l3 F1 B7 `( l4 v2 c( t( s2 U) ~# T! E5 { }; % @& J2 B6 {+ T8 h l& w' W7 f+ E0 B, u. k$ [clocks {" x' A; `& o( O+ a3 p; {, Z# ? 7 m3 D0 Y' |' ^6 ^* t clk_ext_camera: clk-ext-camera {. C9 [0 L- a3 `) N% y# M2 i5 w2 M $ q* i; o7 ?: N! w; z: c: n#clock-cells = ;3 C0 ^( p) O& I2 @ $ v6 P. ?9 Q8 @8 O _ compatible = "fixed-clock";. q. ~2 N% T8 V$ Y, n* H / C( ~. M. E7 Z1 U! Hclock-frequency = ; ! Y5 f; ~9 o( `5 h ) @7 p( w2 y$ |& r}; * P7 @ W$ P5 ^9 P; F) }9 H# k : m% V! _; b2 m0 a/ _, _: A5 A! n- H}; - s% T& W; Q }+ c( f# n & U! I0 {4 T5 `/ ~8 d3 Z}; 3 d: y; v, E: d4 W- Q% ^! K$ M; |- {6 C' c, F: [ D" ]7 N 4.配置内核 ' D+ H# L6 J5 X4 A" p, D8 Z配置内核支持ov5640，并列出主要选项，如下 ( m1 d$ y# s/ v . N/ C F& R% N( flinux@ubuntu make menuconfig9 R8 c- K5 j# \ 1 @( [# @& L/ j3 _6 Q: X Device Drivers --->+ ?, i! [& b* ?% X( C / L, }- F2 l( X2 v7 h ]) l Multimedia support ---> ' @7 u# e4 X0 G0 T. g2 _$ B% ~ V4L platform devices ---> 5 z* n, k: O4 l r7 \: _0 w4 S' G) I% J- U. q' F$ h- G STM32 Digital Camera Memory Interface (DCMI) support6 w: T' z" |7 X3 Z$ |1 k + b( J2 m' t1 l. m: `4 C% zI2C Encoders, decoders, sensors and other helper chips ---> ) \4 n [# b4 e) k- ?3 b. ?( f, @ % g P6 C; n3 j# q! O' H) _ OmniVision OV5640 sensor support# C3 z! c* p- D y+ t w5 e/ X 5.编译内核及设备树linux@ubuntu make -j4 uImage dtbs LOADADDR=0xC20000406.重启测试" m" u, G0 e0 `2 \6 L 将编译好的设备树和内核镜像拷贝到/tftpboot目录下，通过tftp引导内核，系统启动后启动信息中包含如下信息：& A' m0 r/ O9 ~ 8 r5 k) V2 Q5 s) u3 f( x " z* I" N/ C: V0 T( ] + @1 T- x7 f2 {2 ?在屏幕的界面上选择“Camera preview”应用进入摄像头预览程序，启动界面后即可看到摄像头实时采集的图像。 5 S" z$ q' w k# @ 4 j6 \# O7 r# o' b4 C; p6 O 7 W! |% a' X! O l% B 1 }9 c8 t/ l' w5 T4 T———————————————— ' F* R# k' ^# v3 T; j, y/ l1 n# [1 m版权声明：华清远见IT开放实验室6 {5 {) |7 ]% H0 q, ` . R7 t8 | Y' N4 I6 o4 g 8 F+ y: o' H4 |9 a

STM32MP157 Linux系统移植开发篇17：Linux内核摄像头驱动移植

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STMCU小助手发布时间：2022-9-29 18:36

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文章简介:	STM32MP157 Linux系统移植开发篇17：Linux内核摄像头驱动移植

1.实验原理
DCMI(Digital Camera Interface)，DCMI是一个同步并行接口，能够从外部8bit、10bit、12bit或14bit的CMOS摄像头接收高速数据流，支持不同的数据格式：YCbCr4:2:2/RGB565渐进式视频和压缩数据（JPEG）。

FS-MP1A可以外接8bit的COM Camera，接口定义如下:

接口与MPU管脚对应关系如下：

内核中ST对STM32MP15x系列芯片的设备树资源了做了定义，可参见：

arch/arm/boot/dts/stm32mp151.dtsi

stm32mp151中dcmi定义如下：

dcmi: dcmi@4c006000 {

compatible = "st,stm32-dcmi";

reg = <0x4c006000 0x400>;

interrupts = <GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>;

resets = <&rcc CAMITF_R>;

clocks = <&rcc DCMI>;

clock-names = "mclk";

dmas = <&dmamux1 75 0x400 0xe0000001>;

dma-names = "tx";

status = "disabled";

};

上述代码只对dcmi做了基本的初始化，并没有针对不同的硬件设计做适配，所以需结合硬件补全设备树节点信息。

参考帮助文档及内核中其它STM32MP157设备树中对于dcmi的定义，修改dcmi内容如下：

&dcmi {

status = "okay";

pinctrl-names = "default", "sleep";

pinctrl-0 = <&dcmi_pins_a>;

pinctrl-1 = <&dcmi_sleep_pins_a>;

port {

dcmi_0: endpoint {

remote-endpoint = <&ov5640_0>;

bus-width = <8>;

hsync-active = <0>;

vsync-active = <0>;

pclk-sample = <1>;

pclk-max-frequency = <77000000>;

};

};

};

由于stm32mp15-pinctrl.dtsi中对于DCMI管脚的定义与FS-MP1A实际使用管脚一致，所以无需修改

1.CMOS Camera设备树节点
FS-MP1A支持多款COMS Camera，本节以ov5640为例：

参考帮助文档及内核中其它STM32MP157设备树中对于ov5640的定义，修改dcmi内容如下：

ov5640: camera@3c {

compatible = "ovti,ov5640";

reg = <0x3c>;

clocks = <&clk_ext_camera>;

clock-names = "xclk";

DOVDD-supply = <&v2v8>;

powerdown-gpios = <&gpioa 4 (GPIO_ACTIVE_HIGH | GPIO_PUSH_PULL)>;

reset-gpios = <&gpioa 3 (GPIO_ACTIVE_LOW | GPIO_PUSH_PULL)>;

rotation = <180>;

status = "okay";

port {

ov5640_0: endpoint {

remote-endpoint = <&dcmi_0>;

bus-width = <8>;

data-shift = <2>; /* lines 9:2 are used */

hsync-active = <0>;

vsync-active = <0>;

pclk-sample = <1>;

pclk-max-frequency = <77000000>;

};

};

};

2.2.8V电源定义
前文已经说过如何添加电源节点，本节不再重复，在根节点添加&v2v8节点，内容如下：

v2v8_audio: regulator-v2v8 {

compatible = "regulator-fixed";

regulator-name = "v2v8";

regulator-min-microvolt = <2800000>;

regulator-max-microvolt = <2800000>;

regulator-always-on;

regulator-boot-on;

};

3.24M时钟定义
参考文档：

Documentation/devicetree/bindings/clock/fixed-clock.yaml

参考帮助文档或内核中其他设备树文件，对于时钟的定义，增加内容如下：

clocks {

clk_ext_camera: clk-ext-camera {

#clock-cells = <0>;

compatible = "fixed-clock";

clock-frequency = <24000000>;

};

};
8 A* l$ F, M7 t- e1 c2 e
2.实验目的
熟悉基于Linux操作系统下的摄像头设备驱动移植配置过程。

3.实验平台
华清远见开发环境，FS-MP1A平台；

4.实验步骤
导入交叉编译工具链
linux@ubuntu

source /opt/st/stm32mp1/3.1-openstlinux-5.4-dunfell-mp1-20-06-24/environment-setup-cortexa7t2hf-neon-vfpv4-ostl-linux-gnueabi

1.增加DCMI设备树节点
修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件，在文件末尾添加如下内容：

&dcmi {

status = "okay";

pinctrl-names = "default", "sleep";

pinctrl-0 = <&dcmi_pins_a>;

pinctrl-1 = <&dcmi_sleep_pins_a>;

port {

dcmi_0: endpoint {

remote-endpoint = <&ov5640_0>;

bus-width = <8>;

hsync-active = <0>;

vsync-active = <0>;

pclk-sample = <1>;

pclk-max-frequency = <77000000>;

};

};

};

2.增加OV5640节点
修改arch/arm/dts/stm32mp15xx-fsmp1x.dtsi文件，在I2C5节点中添加OV5640设备信息，红色字体为增加内容：

&i2c5 {

pinctrl-names = "default", "sleep";

pinctrl-0 = <&i2c5_pins_a>;

……

ov5640: camera@3c {

compatible = "ovti,ov5640";

reg = <0x3c>;

clocks = <&clk_ext_camera>;

clock-names = "xclk";

DOVDD-supply = <&v2v8>;

powerdown-gpios = <&gpioa 4 (GPIO_ACTIVE_HIGH | GPIO_PUSH_PULL)>;

reset-gpios = <&gpioa 3 (GPIO_ACTIVE_LOW | GPIO_PUSH_PULL)>;

rotation = <180>;

status = "okay";

port {

ov5640_0: endpoint {

remote-endpoint = <&dcmi_0>;

bus-width = <8>;

data-shift = <2>; /* lines 9:2 are used */

hsync-active = <0>;

vsync-active = <0>;

pclk-sample = <1>;

pclk-max-frequency = <77000000>;

};

};

};

};

3.增加2.8V电源和24M时钟
修改arch/arm/dts/stm32mp15xx-fsmp1x.dtsi文件，在根节点最后添加2.8V电源和24M时钟，红色字体为增加内容：

/ {

memory@c0000000 {

device_type = "memory";

reg = <0xc0000000 0x20000000>;

};

……

v2v8: regulator-2p8v {

compatible = "regulator-fixed";

regulator-name = "v2v8";

regulator-min-microvolt = <2800000>;

regulator-max-microvolt = <2800000>;

regulator-always-on;

regulator-boot-on;

};

clocks {

clk_ext_camera: clk-ext-camera {

#clock-cells = <0>;

compatible = "fixed-clock";

clock-frequency = <24000000>;

};

};

};

4.配置内核
配置内核支持ov5640，并列出主要选项，如下

linux@ubuntu

make menuconfig

Device Drivers --->

<*> Multimedia support --->
V4L platform devices --->

<*> STM32 Digital Camera Memory Interface (DCMI) support

I2C Encoders, decoders, sensors and other helper chips --->

<*> OmniVision OV5640 sensor support
5.编译内核及设备树linux@ubuntu

make -j4 uImage dtbs LOADADDR=0xC20000406.重启测试
将编译好的设备树和内核镜像拷贝到/tftpboot目录下，通过tftp引导内核，系统启动后启动信息中包含如下信息：