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GPIO模拟I2C

分类： LINUX

2017-11-08 23:14:34

原文地址：GPIO模拟I2C 作者：caijicheng2006


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  1. nmi_gpio_i2c.h

  3. int nmi_i2c_init(void);

  5. void nmi_i2c_deinit(void);

  7. int nmi_i2c_read(unsigned char, unsigned char *, unsigned long);

  9. int nmi_i2c_write(unsigned char, unsigned char *, unsigned long);

  11. nmi_gpio_i2c.c
  12. /******************************************************************************

  14. **

  16. **    Copyright (c) Newport Media Inc. All rights reserved.

  18. **

  20. **     Module Name: nmidrv_i2c.c

  22. **    

  24. **        This module implements the i2c interface NMI ATV

  26. **

  28. **

  30. *******************************************************************************/

  32. #include <linux/kernel.h>

  34. #include <linux/init.h>

  36. //#include <linux/android_pmem.h>

  38. #include <mach/hardware.h>

  40. #include <asm/mach-types.h>

  42. #include <asm/mach/arch.h>

  44. #include <asm/mach/map.h>

  46. #include <mach/board.h>

  48. #include <mach/hardware.h>

  50. #include <asm/io.h>

  52. #include <asm/delay.h>

  54. #include <mach/gpio.h>

  56. #include <linux/clk.h>

  58. #include <mach/mfp.h>

  60. #include <linux/i2c.h>

  62. #include <linux/i2c-gpio.h>

  64. #include "nmi_gpio_i2c.h"

  66. #include "nm5625_kernel.h"

  68. #include <linux/delay.h>







  76. #define NMI_SDA_PIN    81

  78. #define NMI_SCL_PIN    80



  82. static unsigned long I2C_func_cfg[] /*__initdata*/ = {

  84.     MFP_CFG_X(SDA, GPIO, DS3, F_PULL_UP, F_PULL_UP, IO_OE),

  86.         MFP_CFG_X(SCL, GPIO, DS3, F_PULL_UP, F_PULL_UP, IO_OE),

  88. };



  92. static unsigned long I2C_std_func_cfg[] = {
  93.     MFP_CFG_X(SDA, AF0, DS3, F_PULL_UP, F_PULL_UP, IO_NONE),

  95.         MFP_CFG_X(SCL, AF0, DS3, F_PULL_UP, F_PULL_UP, IO_NONE),
  96. };



  100. /******************************************************************************

  102. **

  104. **    I2c Defines

  106. **

  108. *******************************************************************************/

  110. //#undef _DRIVE_ //this mode is nmi600 Recommend mode. please don't change it.

  112. #define _DRIVE_

  114. #define I2C_DELAY_UNIT 2



  118. /*#define set_sda_output() mt_set_gpio_dir(NMI_SDA_PIN,1); \

  120.                                                        mt_set_gpio_out(NMI_SDA_PIN,0)

  122. #define set_sda_input() mt_set_gpio_dir(NMI_SDA_PIN,0)

  124. #define set_scl_output() mt_set_gpio_dir(NMI_SCL_PIN,1); \

  126.                                                         mt_set_gpio_out(NMI_SCL_PIN,0)

  128. #define set_scl_input() mt_set_gpio_dir(NMI_SCL_PIN,0)*/



  132. #define set_sda_output()                gpio_direction_output(NMI_SDA_PIN,0)

  134. #define set_sda_input()                    gpio_direction_input(NMI_SDA_PIN)        

  136. #define set_scl_output()                gpio_direction_output(NMI_SCL_PIN,0)

  138. #define set_scl_input()                    gpio_direction_input(NMI_SCL_PIN)



  142. #ifdef _DRIVE_

  144. #define set_i2c_scl_PIN             gpio_direction_output(NMI_SCL_PIN,1)    

  146. #define clr_i2c_scl_PIN             gpio_direction_output(NMI_SCL_PIN,0)

  148. #define set_i2c_sda_PIN             gpio_direction_output(NMI_SDA_PIN,1)

  150. #define clr_i2c_sda_PIN          gpio_direction_output(NMI_SDA_PIN,0)

  152. #else

  154. /*#define set_i2c_scl_PIN             mt_set_gpio_out(NMI_SCL_PIN,1)    

  156. #define clr_i2c_scl_PIN             mt_set_gpio_out(NMI_SCL_PIN,0)

  158. #define set_i2c_sda_PIN             mt_set_gpio_out(NMI_SDA_PIN,0)

  160. #define clr_i2c_sda_PIN          mt_set_gpio_out(NMI_SDA_PIN,1)*/

  162. #endif



  166. //#define get_i2c_sda_PIN             gpio_direction_input(NMI_SDA_PIN);gpio_get_value(NMI_SDA_PIN)

  168. //#define get_i2c_scl_PIN          gpio_direction_input(NMI_SCL_PIN);gpio_get_value(NMI_SCL_PIN)

  170. #define get_i2c_sda_PIN                gpio_get_value(NMI_SDA_PIN)

  172. #define get_i2c_scl_PIN                gpio_get_value(NMI_SCL_PIN)





  178. /******************************************************************************

  180. **

  182. **    I2c Platform Functions

  184. **

  186. *******************************************************************************/



  190. static void i2c_delay(unsigned int time)

  192. {

  194. #if 0

  196.     while(time--) {    

  198.         ;

  200.     }

  202. #else

  204.     udelay(time);

  206. #endif

  208. }



  212. static void i2c_begin(void)

  214. {

  216. #ifdef _DRIVE_



  220.     /* set SDA to high */

  222.     set_i2c_sda_PIN;

  224.     i2c_delay(I2C_DELAY_UNIT << 0);

  226.     

  228.     /* set SCL to high */

  230.     set_i2c_scl_PIN;

  232.     i2c_delay(I2C_DELAY_UNIT << 0);



  236.     /* set SDA to low */

  238.     clr_i2c_sda_PIN;

  240.     i2c_delay(I2C_DELAY_UNIT << 0);



  244.     /* set SCL to low */

  246.     clr_i2c_scl_PIN;        

  248.     i2c_delay(I2C_DELAY_UNIT << 0);



  252. #else



  256.     /* set SDA to high */

  258.     set_sda_input();

  260.     i2c_delay(I2C_DELAY_UNIT << 0);



  264.     /* set SCL to high */

  266.     set_scl_input();

  268.     i2c_delay(I2C_DELAY_UNIT << 0);



  272.     /* set SDA to low */

  274.     set_sda_output();

  276.     i2c_delay(I2C_DELAY_UNIT << 0);



  280.     /* set SCL to low */

  282.     set_scl_output();        

  284.     i2c_delay(I2C_DELAY_UNIT << 0);

  286. #endif



  290. }



  294. static void i2c_end(void)

  296. {

  298. #ifdef _DRIVE_

  300.     /* set SDA to low */

  302.     clr_i2c_sda_PIN;    

  304.     i2c_delay(I2C_DELAY_UNIT << 2);



  308.     /* set SCL to high */

  310.     set_i2c_scl_PIN;

  312.     i2c_delay(I2C_DELAY_UNIT << 0);



  316.     /* set SDA to high */

  318.     set_i2c_sda_PIN;        

  320.     i2c_delay(I2C_DELAY_UNIT << 0);



  324. #else

  326.     set_sda_output();

  328.     i2c_delay(I2C_DELAY_UNIT << 2);

  330.     set_scl_input();

  332.     i2c_delay(I2C_DELAY_UNIT << 3);

  334.     set_sda_input();

  336.     i2c_delay(I2C_DELAY_UNIT << 4);

  338. #endif

  340. }



  344. static void i2c_write_ask(unsigned char flag)

  346. {

  348. #ifdef _DRIVE_

  350.     /* set SDA to high to ack */

  352.     if(flag)

  354.         set_i2c_sda_PIN;

  356.     else

  358.         clr_i2c_sda_PIN;

  360.     i2c_delay(I2C_DELAY_UNIT << 0);



  364.     /* toggle clock */

  366.     set_i2c_scl_PIN;

  368.     i2c_delay(I2C_DELAY_UNIT << 0);

  370.     clr_i2c_scl_PIN;

  372.     i2c_delay(I2C_DELAY_UNIT << 0);



  376.     /* set SDA to 1 */

  378.     set_i2c_sda_PIN;

  380.     i2c_delay(I2C_DELAY_UNIT << 0);



  384. #else



  388.        //set_sda_output();



  392.     if(flag)

  394.         set_sda_input();

  396.     //else

  398.         //set_sda_output();

  400.     

  402.     i2c_delay(I2C_DELAY_UNIT << 0);

  404.     set_scl_input();

  406.     i2c_delay(I2C_DELAY_UNIT << 0);

  408.     set_scl_output();

  410.     i2c_delay(I2C_DELAY_UNIT << 0);

  412.     set_sda_input();

  414.     i2c_delay(I2C_DELAY_UNIT << 0);

  416. #endif

  418. }



  422. static unsigned char i2c_read_ack(void)

  424. {

  426.     unsigned char ret;



  430. #ifdef _DRIVE_

  432.     /* set SDA to input */

  434.     set_sda_input();

  436.     /* delay */

  438.     i2c_delay(I2C_DELAY_UNIT << 0);

  440.     

  442.     /* read */

  444.     //gpio_direction_input(NMI_SDA_PIN);

  446.     if (!get_i2c_sda_PIN) {

  448.         ret = 1;

  450.     } else {

  452.         ret = 0;

  454.         dPrint(N_ERR,"[MTKI2C] 1. i2c_read_ack (Error.. No Ack received)\n");

  456.         i2c_delay(I2C_DELAY_UNIT << 0);

  458.         if (!get_i2c_sda_PIN) {

  460.             ret = 1;

  462.             dPrint(N_ERR,"[MTKI2C] 2.i2c_read_ack (Correct after additional delay.)\n");    

  464.         } else {

  466.             ret = 0;

  468.             dPrint(N_ERR,"[MTKI2C] 2.i2c_read_ack (Error.. No Ack received)\n");

  470.         }

  472.     }



  476.     /* set SCL high */

  478.     set_i2c_scl_PIN;

  480.     i2c_delay(I2C_DELAY_UNIT << 0);



  484.     /* set SCL low */

  486.     clr_i2c_scl_PIN;

  488.     i2c_delay(I2C_DELAY_UNIT << 0);



  492.     /* set SDA back to output */

  494.     set_sda_output();



  498. #else



  502.     set_sda_input();

  504.     i2c_delay(I2C_DELAY_UNIT << 0);

  506.     

  508.     //gpio_direction_input(NMI_SDA_PIN);

  510.     if (!get_i2c_sda_PIN) {

  512.         ret = 1;

  514.     } else {

  516.         ret = 0;

  518.         dPrint(N_ERR,"[MTKI2C] 1. i2c_read_ack (Error.. No Ack received)\n");

  520.         i2c_delay(I2C_DELAY_UNIT << 0);

  522.         if (!get_i2c_sda_PIN) {

  524.             ret = 1;

  526.             dPrint(N_ERR,"[MTKI2C] 2.i2c_read_ack (Correct after additional delay.)\n");    

  528.         } else {

  530.             ret = 0;

  532.             dPrint(N_ERR,"[MTKI2C] 2.i2c_read_ack (Error.. No Ack received)\n");

  534.         }

  536.     }

  538.     

  540.     set_scl_input();

  542.     i2c_delay(I2C_DELAY_UNIT << 0);

  544.     set_scl_output();

  546.     i2c_delay(I2C_DELAY_UNIT << 0);

  548.     

  550. #endif

  552.     return ret;

  554. }



  558. static unsigned char i2c_read_byte(void)

  560. {

  562.     unsigned char i;

  564.     unsigned char ret = 0;



  568. #ifdef _DRIVE_



  572.     /* set SDA input */

  574.     set_sda_input();

  576.     

  578.     /* loop */

  580.     for (i = 0; i < 8; i++) {            

  582.         /* delay */

  584.         i2c_delay(I2C_DELAY_UNIT << 0);



  588.         /* set SCL high */

  590.         set_i2c_scl_PIN;

  592.         /* delay */

  594.         i2c_delay(I2C_DELAY_UNIT << 0);



  598.         /* read SDA */

  600.         ret    = ret<<1;

  602.         //gpio_direction_input(NMI_SDA_PIN);

  604.         if (get_i2c_sda_PIN)

  606.             ret |= 1;

  608.         /* delay */

  610.         i2c_delay(I2C_DELAY_UNIT << 0);



  614.         /* set SCL low */

  616.         clr_i2c_scl_PIN;

  618.         /* delay */

  620.         i2c_delay(I2C_DELAY_UNIT << 0);



  624.         /* if end, set SDA output */

  626.         if (i == 7) {

  628.             set_sda_output();

  630.           }

  632.         /* delay */

  634.          i2c_delay(I2C_DELAY_UNIT << 0);

  636.     }    



  640. #else

  642.     int retry,retry_val = 10000000;



  646.     ret    = 0;



  650.     set_sda_input();

  652.     for (i = 0; i < 8; i++) {            

  654.         i2c_delay(I2C_DELAY_UNIT << 0);



  658.         set_scl_input();    



  662.         i2c_delay(I2C_DELAY_UNIT << 0);

  664.         ret    = ret<<1;

  666.         if (get_i2c_sda_PIN)

  668.             ret |= 1;

  670.         i2c_delay(I2C_DELAY_UNIT << 0);



  674.         retry = retry_val;

  676.         while (retry >= 0)

  678.         {

  680.             if (get_i2c_scl_PIN)

  682.                 break;

  684.             else

  686.             {

  688.                 i2c_delay(I2C_DELAY_UNIT << 0);

  690.                 retry--;

  692.             }

  694.         }



  698.         //if (retry != retry_val)

  700.         if (retry < (retry_val-10000))

  702.         {

  704.             //NMI_ERROR("[MTKI2C] i2c_read_byte: retry = %d\n",retry);

  706.         }



  710.         set_scl_output();

  712.               i2c_delay(I2C_DELAY_UNIT << 0);



  716.         if (i==7){

  718.         set_sda_output();

  720.               }

  722.              i2c_delay(I2C_DELAY_UNIT << 0);

  724.     }        



  728. #endif    



  732.     return ret;

  734. }



  738. static unsigned char i2c_write_byte(unsigned char data)

  740. {

  742.     unsigned char i;



  746. #ifdef _DRIVE_

  748.     /* loop */

  750.     for    (i = 0; i < 8; i++) {

  752.         /* set SDA high or low depend on the data bit */

  754.         if (data & 0x80)

  756.             set_i2c_sda_PIN;

  758.         else

  760.             clr_i2c_sda_PIN;

  762.         /* delay */

  764.         i2c_delay(I2C_DELAY_UNIT << 0);



  768.         data <<= 1;



  772.         /* set SCL high */

  774.         set_i2c_scl_PIN;

  776.         /* delay */

  778.         i2c_delay(I2C_DELAY_UNIT << 0);



  782.         /* set SCL low */

  784.         clr_i2c_scl_PIN;

  786.         /* delay */

  788.         i2c_delay(I2C_DELAY_UNIT << 0);

  790.     }

  792. #else

  794.     int retry, retry_val = 10000000;



  798.     //set_sda_output();



  802.     for    (i = 0; i < 8; i++) {

  804.         if (data & 0x80)

  806.             set_sda_input();

  808.         else

  810.             set_sda_output();



  814.         data <<= 1;



  818.         i2c_delay(I2C_DELAY_UNIT << 0);

  820.         set_scl_input();

  822.         i2c_delay(I2C_DELAY_UNIT << 0);

  824.         retry = retry_val;

  826.         while (retry >= 0)

  828.         {

  830.             if (get_i2c_scl_PIN)

  832.                 break;

  834.             else

  836.             {

  838.                 i2c_delay(I2C_DELAY_UNIT << 0);

  840.                 retry--;

  842.             }

  844.         }



  848.         //if (retry != retry_val)

  850.         if (retry < (retry_val-10000))

  852.         {

  854.             dPrint(N_TRACE,"i2c write_byte: retry = %d\n",retry);

  856.         }

  858.         set_scl_output();        

  860.         i2c_delay(I2C_DELAY_UNIT << 0);

  862.     }

  864.     

  866. #endif

  868.     

  870.     return i2c_read_ack();

  872. }



  876. /******************************************************************************

  878. **

  880. **    I2c Global Functions

  882. **

  884. *******************************************************************************/



  888. int nmi_i2c_init(void)

  890. {

  892.     dPrint(N_TRACE,"nmi_i2c_init: enter...\n");



  896.     sprd_mfp_config(I2C_func_cfg, ARRAY_SIZE(I2C_func_cfg));

  898.     gpio_request(NMI_SCL_PIN,"scl");

  900.     gpio_request(NMI_SDA_PIN,"sda");

  902.     gpio_direction_output(NMI_SCL_PIN,1);

  904.     gpio_direction_output(NMI_SDA_PIN,1);

  906. /*#if 0

  908.        //disable all inside pull( pullup & pulldown)

  910.     NMI_SET_GPIO_PULL_DISABLE(NMI_SDA_PIN);

  912.     NMI_SET_GPIO_PULL_DISABLE(NMI_SCL_PIN);

  914.     //set gpio mode

  916.     NMI_SET_GPIO_MODE_ENABLE(NMI_SDA_PIN);

  918.     NMI_SET_GPIO_MODE_ENABLE(NMI_SCL_PIN);



  922. #ifdef _DRIVE_

  924.     //set output mode

  926.     NMI_SET_GPIO_DIR( NMI_SDA_PIN,1);

  928.     NMI_SET_GPIO_DIR( NMI_SCL_PIN,1);

  930.       //set gpio high

  932.     NMI_SET_GPIO_LEVEL( NMI_SDA_PIN,1);

  934.     NMI_SET_GPIO_LEVEL( NMI_SCL_PIN,1);

  936. #else

  938.     //set input mode

  940.     NMI_SET_GPIO_DIR( NMI_SDA_PIN,0);

  942.     NMI_SET_GPIO_DIR( NMI_SCL_PIN,0);

  944. #endif

  946. #else

  948.     //config scl

  950.     mt_set_gpio_mode(NMI_SCL_PIN,GPIO_MODE_00);

  952.     mt_set_gpio_dir(NMI_SCL_PIN, GPIO_DIR_OUT);

  954.     mt_set_gpio_pull_enable(NMI_SCL_PIN,true);

  956.     mt_set_gpio_pull_select(NMI_SCL_PIN, GPIO_PULL_UP);

  958.     mt_set_gpio_out(NMI_SCL_PIN, GPIO_OUT_ONE);



  962.     //config sda

  964.     mt_set_gpio_mode(NMI_SDA_PIN, GPIO_MODE_00);

  966.     mt_set_gpio_dir(NMI_SDA_PIN, GPIO_DIR_OUT);

  968.     mt_set_gpio_pull_enable(NMI_SDA_PIN,true);

  970.     mt_set_gpio_pull_select(NMI_SDA_PIN, GPIO_PULL_UP);

  972.     mt_set_gpio_out(NMI_SDA_PIN, GPIO_OUT_ONE);

  974. #endif*/

  976.     dPrint(N_TRACE,"nmi_i2c_init: exit...\n");



  980.     return 1;

  982. }



  986. void nmi_i2c_deinit(void)

  988. {

  990.     dPrint(N_TRACE,"nmi_i2c_deinit: enter...\n");



  994.     gpio_free(NMI_SDA_PIN);

  996.     gpio_free(NMI_SCL_PIN);
  997.     sprd_mfp_config(I2C_std_func_cfg, ARRAY_SIZE(I2C_std_func_cfg));

  999. #if 0

  1001.     NMI_SET_GPIO_MODE_ENABLE(NMI_SDA_PIN);

  1003.     NMI_SET_GPIO_MODE_ENABLE(NMI_SCL_PIN);



  1007.     //set as input

  1009.     NMI_SET_GPIO_DIR( NMI_SDA_PIN,0);

  1011.     NMI_SET_GPIO_DIR( NMI_SCL_PIN,0);

  1013. #endif

  1015.     dPrint(N_TRACE,"nmi_i2c_deinit: exit...\n");



  1019. }



  1023. int nmi_i2c_read(unsigned char adr, unsigned char *b, unsigned long sz)

  1025. {

  1027.     int i;



  1031.     i2c_begin();

  1033.     i2c_write_byte((adr << 1)|0x1);



  1037.     for(i = 0; i < sz; i++) {

  1039.      b[i] = i2c_read_byte();    

  1041.         

  1043.      if(i == sz-1)

  1045.             i2c_write_ask(1);    

  1047.      else     

  1049.             i2c_write_ask(0);

  1051.     }



  1055.     i2c_end();

  1057.     return 1;

  1059. }



  1063. int nmi_i2c_write(unsigned char adr, unsigned char *b, unsigned long sz)

  1065. {

  1067.     int i;



  1071.     i2c_begin();



  1075.     i2c_write_byte((adr << 1));

  1077.     for(i = 0; i < sz; i++) {

  1079.         i2c_write_byte(b[i]);

  1081.     }



  1085.     i2c_end();

  1087.     return 1;

  1089. }

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