drivers/i2c/pca9564_i2c.c

   1 /*
   2  * File:         drivers/i2c/pca9564.c
   3  * Based on:     drivers/i2c/s3c44b0_i2c.c
   4  * Author:
   5  *
   6  * Created:      2009-06-23
   7  * Description:  PCA9564 i2c bridge driver
   8  *
   9  * Modified:
  10  *               Copyright 2009 CJSC "NII STT", http://www.niistt.ru/
  11  *
  12  * Bugs:
  13  *
  14  * SPDX-License-Identifier:     GPL-2.0+
  15  */
  16
  17 #include <common.h>
  18 #include <i2c.h>
  19 #include <pca9564.h>
  20 #include <asm/io.h>
  21
  22 #define PCA_STA                 (CONFIG_PCA9564_BASE + 0)
  23 #define PCA_TO                  (CONFIG_PCA9564_BASE + 0)
  24 #define PCA_DAT                 (CONFIG_PCA9564_BASE + (1 << 2))
  25 #define PCA_ADR                 (CONFIG_PCA9564_BASE + (2 << 2))
  26 #define PCA_CON                 (CONFIG_PCA9564_BASE + (3 << 2))
  27
  28 static unsigned char pca_read_reg(unsigned int reg)
  29 {
  30         return readb((void *)reg);
  31 }
  32
  33 static void pca_write_reg(unsigned int reg, unsigned char value)
  34 {
  35         writeb(value, (void *)reg);
  36 }
  37
  38 static int pca_wait_busy(void)
  39 {
  40         unsigned int timeout = 10000;
  41
  42         while (!(pca_read_reg(PCA_CON) & PCA_CON_SI) && --timeout)
  43                 udelay(1);
  44
  45         if (timeout == 0)
  46                 debug("I2C timeout!\n");
  47
  48         debug("CON = 0x%02x, STA = 0x%02x\n", pca_read_reg(PCA_CON),
  49                pca_read_reg(PCA_STA));
  50
  51         return timeout ? 0 : 1;
  52 }
  53
  54 /*=====================================================================*/
  55 /*                         Public Functions                            */
  56 /*=====================================================================*/
  57
  58 /*-----------------------------------------------------------------------
  59  * Initialization
  60  */
  61 void i2c_init(int speed, int slaveaddr)
  62 {
  63         pca_write_reg(PCA_CON, PCA_CON_ENSIO | speed);
  64 }
  65
  66 /*
  67  * Probe the given I2C chip address.  Returns 0 if a chip responded,
  68  * not 0 on failure.
  69  */
  70
  71 int i2c_probe(uchar chip)
  72 {
  73         unsigned char res;
  74
  75         pca_write_reg(PCA_CON, PCA_CON_STA | PCA_CON_ENSIO);
  76         pca_wait_busy();
  77
  78         pca_write_reg(PCA_CON, PCA_CON_STA | PCA_CON_ENSIO);
  79
  80         pca_write_reg(PCA_DAT, (chip << 1) | 1);
  81         res = pca_wait_busy();
  82
  83         if ((res == 0) && (pca_read_reg(PCA_STA) == 0x48))
  84                 res = 1;
  85
  86         pca_write_reg(PCA_CON, PCA_CON_STO | PCA_CON_ENSIO);
  87
  88         return res;
  89 }
  90
  91 /*
  92  * Read/Write interface:
  93  *   chip:    I2C chip address, range 0..127
  94  *   addr:    Memory (register) address within the chip
  95  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
  96  *              memories, 0 for register type devices with only one
  97  *              register)
  98  *   buffer:  Where to read/write the data
  99  *   len:     How many bytes to read/write
 100  *
 101  *   Returns: 0 on success, not 0 on failure
 102  */
 103 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 104 {
 105         int i;
 106
 107         pca_write_reg(PCA_CON, PCA_CON_ENSIO | PCA_CON_STA);
 108         pca_wait_busy();
 109
 110         pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 111
 112         pca_write_reg(PCA_DAT, (chip << 1));
 113         pca_wait_busy();
 114         pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 115
 116         if (alen > 0) {
 117                 pca_write_reg(PCA_DAT, addr);
 118                 pca_wait_busy();
 119                 pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 120         }
 121
 122         pca_write_reg(PCA_CON, PCA_CON_ENSIO | PCA_CON_STO);
 123
 124         udelay(500);
 125
 126         pca_write_reg(PCA_CON, PCA_CON_ENSIO | PCA_CON_STA);
 127         pca_wait_busy();
 128         pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 129
 130         pca_write_reg(PCA_DAT, (chip << 1) | 1);
 131         pca_wait_busy();
 132
 133         for (i = 0; i < len; ++i) {
 134                 if (i == len - 1)
 135                         pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 136                 else
 137                         pca_write_reg(PCA_CON, PCA_CON_ENSIO | PCA_CON_AA);
 138
 139                 pca_wait_busy();
 140                 buffer[i] = pca_read_reg(PCA_DAT);
 141
 142         }
 143
 144         pca_write_reg(PCA_CON, PCA_CON_ENSIO | PCA_CON_STO);
 145
 146         return 0;
 147 }
 148
 149 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 150 {
 151         int i;
 152
 153         pca_write_reg(PCA_CON, PCA_CON_ENSIO | PCA_CON_STA);
 154         pca_wait_busy();
 155         pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 156
 157         pca_write_reg(PCA_DAT, chip << 1);
 158         pca_wait_busy();
 159         pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 160
 161         if (alen > 0) {
 162                 pca_write_reg(PCA_DAT, addr);
 163                 pca_wait_busy();
 164                 pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 165         }
 166
 167         for (i = 0; i < len; ++i) {
 168                 pca_write_reg(PCA_DAT, buffer[i]);
 169                 pca_wait_busy();
 170                 pca_write_reg(PCA_CON, PCA_CON_ENSIO);
 171         }
 172
 173         pca_write_reg(PCA_CON, PCA_CON_STO | PCA_CON_ENSIO);
 174
 175         return 0;
 176 }