linux/drivers/video/fbdev/mb862xx/mb862xx-i2c.c
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   1/*
   2 * Coral-P(A)/Lime I2C adapter driver
   3 *
   4 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 */
  11
  12#include <linux/fb.h>
  13#include <linux/i2c.h>
  14#include <linux/io.h>
  15#include <linux/delay.h>
  16#include <linux/export.h>
  17
  18#include "mb862xxfb.h"
  19#include "mb862xx_reg.h"
  20
  21static int mb862xx_i2c_wait_event(struct i2c_adapter *adap)
  22{
  23        struct mb862xxfb_par *par = adap->algo_data;
  24        u32 reg;
  25
  26        do {
  27                udelay(10);
  28                reg = inreg(i2c, GC_I2C_BCR);
  29                if (reg & (I2C_INT | I2C_BER))
  30                        break;
  31        } while (1);
  32
  33        return (reg & I2C_BER) ? 0 : 1;
  34}
  35
  36static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr)
  37{
  38        struct mb862xxfb_par *par = adap->algo_data;
  39
  40        outreg(i2c, GC_I2C_DAR, addr);
  41        outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE);
  42        outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START);
  43        if (!mb862xx_i2c_wait_event(adap))
  44                return -EIO;
  45        par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
  46        return par->i2c_rs;
  47}
  48
  49static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte)
  50{
  51        struct mb862xxfb_par *par = adap->algo_data;
  52
  53        outreg(i2c, GC_I2C_DAR, byte);
  54        outreg(i2c, GC_I2C_BCR, I2C_START);
  55        if (!mb862xx_i2c_wait_event(adap))
  56                return -EIO;
  57        return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB);
  58}
  59
  60static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last)
  61{
  62        struct mb862xxfb_par *par = adap->algo_data;
  63
  64        outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK));
  65        if (!mb862xx_i2c_wait_event(adap))
  66                return 0;
  67        *byte = inreg(i2c, GC_I2C_DAR);
  68        return 1;
  69}
  70
  71static void mb862xx_i2c_stop(struct i2c_adapter *adap)
  72{
  73        struct mb862xxfb_par *par = adap->algo_data;
  74
  75        outreg(i2c, GC_I2C_BCR, I2C_STOP);
  76        outreg(i2c, GC_I2C_CCR, I2C_DISABLE);
  77        par->i2c_rs = 0;
  78}
  79
  80static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m)
  81{
  82        int i, ret = 0;
  83        int last = m->len - 1;
  84
  85        for (i = 0; i < m->len; i++) {
  86                if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) {
  87                        ret = -EIO;
  88                        break;
  89                }
  90        }
  91        return ret;
  92}
  93
  94static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m)
  95{
  96        int i, ret = 0;
  97
  98        for (i = 0; i < m->len; i++) {
  99                if (!mb862xx_i2c_write_byte(adap, m->buf[i])) {
 100                        ret = -EIO;
 101                        break;
 102                }
 103        }
 104        return ret;
 105}
 106
 107static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 108                        int num)
 109{
 110        struct mb862xxfb_par *par = adap->algo_data;
 111        struct i2c_msg *m;
 112        int addr;
 113        int i = 0, err = 0;
 114
 115        dev_dbg(par->dev, "%s: %d msgs\n", __func__, num);
 116
 117        for (i = 0; i < num; i++) {
 118                m = &msgs[i];
 119                if (!m->len) {
 120                        dev_dbg(par->dev, "%s: null msgs\n", __func__);
 121                        continue;
 122                }
 123                addr = m->addr;
 124                if (m->flags & I2C_M_RD)
 125                        addr |= 1;
 126
 127                err = mb862xx_i2c_do_address(adap, addr);
 128                if (err < 0)
 129                        break;
 130                if (m->flags & I2C_M_RD)
 131                        err = mb862xx_i2c_read(adap, m);
 132                else
 133                        err = mb862xx_i2c_write(adap, m);
 134        }
 135
 136        if (i)
 137                mb862xx_i2c_stop(adap);
 138
 139        return (err < 0) ? err : i;
 140}
 141
 142static u32 mb862xx_func(struct i2c_adapter *adap)
 143{
 144        return I2C_FUNC_SMBUS_BYTE_DATA;
 145}
 146
 147static const struct i2c_algorithm mb862xx_algo = {
 148        .master_xfer    = mb862xx_xfer,
 149        .functionality  = mb862xx_func,
 150};
 151
 152static struct i2c_adapter mb862xx_i2c_adapter = {
 153        .name           = "MB862xx I2C adapter",
 154        .algo           = &mb862xx_algo,
 155        .owner          = THIS_MODULE,
 156};
 157
 158int mb862xx_i2c_init(struct mb862xxfb_par *par)
 159{
 160        mb862xx_i2c_adapter.algo_data = par;
 161        par->adap = &mb862xx_i2c_adapter;
 162
 163        return i2c_add_adapter(par->adap);
 164}
 165
 166void mb862xx_i2c_exit(struct mb862xxfb_par *par)
 167{
 168        if (par->adap) {
 169                i2c_del_adapter(par->adap);
 170                par->adap = NULL;
 171        }
 172}
 173