drivers/i2c/lpc_i2c.c

   1 /* Author: Domen Puncer <domen@cba.si>.  License: WTFPL, see file LICENSE */
   2 #include <stdio.h>
   3 #include <errno.h>
   4 #include <types.h>
   5 #include <sem.h>
   6 #include <interrupt.h>
   7 #include <compiler.h>
   8 #include <drivers/i2c.h>
   9 #include <drivers/lpc_i2c.h>
  10
  11
  12
  13 #define CON_AA   (1<<2)
  14 #define CON_SI   (1<<3)
  15 #define CON_STO  (1<<4)
  16 #define CON_STA  (1<<5)
  17 #define CON_I2EN (1<<6)
  18
  19
  20 static void lpc_i2c_init(struct i2c_master *master)
  21 {
  22         struct lpc_i2c *i2c_data = master->priv;
  23         struct lpc_i2c_regs *i2c = i2c_data->regs;
  24         int speed = master->speed;
  25
  26         i2c->CONCLR = CON_AA | CON_SI | CON_STA | CON_I2EN;
  27         speed = i2c_data->pclk/speed/2;
  28         if (speed < 4)
  29                 speed = 4;
  30         if (speed > 0xffff)
  31                 speed = 0xffff;
  32
  33         i2c->SCLH = speed;
  34         i2c->SCLL = speed;
  35         i2c->CONSET = CON_I2EN; /* slave disabled */
  36 }
  37
  38
  39 static void lpc_i2c_handler(struct i2c_master *master)
  40 {
  41         struct lpc_i2c *i2c_data = master->priv;
  42         struct lpc_i2c_regs *i2c = i2c_data->regs;
  43
  44         irq_ack(i2c_data->irq);
  45         i2c_state_machine(master, i2c->STAT);
  46         i2c->CONCLR = CON_SI;
  47 }
  48
  49 /* TODO find some nicer way to do this */
  50 #ifdef MACH_LPC21XX
  51 static struct i2c_irq_data {
  52         struct i2c_master *master;
  53 } i2c_irq_data[2];
  54
  55 void __interrupt i2c0_handler()
  56 {
  57         lpc_i2c_handler(i2c_irq_data[0].master);
  58 }
  59
  60 void __interrupt i2c1_handler()
  61 {
  62         lpc_i2c_handler(i2c_irq_data[1].master);
  63 }
  64 #endif
  65 #ifdef MACH_LPC13XX
  66 static struct i2c_irq_data {
  67         struct i2c_master *master;
  68 } i2c_irq_data[1];
  69
  70 void __interrupt i2c_irqhandler()
  71 {
  72         lpc_i2c_handler(i2c_irq_data[0].master);
  73 }
  74 #endif
  75
  76 static void lpc_i2c_start(struct i2c_master *master)
  77 {
  78         struct lpc_i2c *i2c_data = master->priv;
  79         struct lpc_i2c_regs *i2c = i2c_data->regs;
  80         i2c->CONSET = CON_STA;
  81 }
  82
  83 static void lpc_i2c_restart(struct i2c_master *master)
  84 {
  85         struct lpc_i2c *i2c_data = master->priv;
  86         struct lpc_i2c_regs *i2c = i2c_data->regs;
  87         i2c->CONSET = CON_STA; /* user must clear it */
  88 }
  89
  90 static void lpc_i2c_stop(struct i2c_master *master)
  91 {
  92         struct lpc_i2c *i2c_data = master->priv;
  93         struct lpc_i2c_regs *i2c = i2c_data->regs;
  94         i2c->CONCLR = CON_AA; /* clear ack bit / slave enabled bit */
  95         i2c->CONSET = CON_STO; /* auto cleared */
  96 }
  97
  98 static void lpc_i2c_ack(struct i2c_master *master, int ack)
  99 {
 100         struct lpc_i2c *i2c_data = master->priv;
 101         struct lpc_i2c_regs *i2c = i2c_data->regs;
 102         if (ack)
 103                 i2c->CONSET = CON_AA; /* set ack bit for next received byte */
 104         else
 105                 i2c->CONCLR = CON_AA; /* clear ack bit for next received byte */
 106 }
 107
 108 static void lpc_i2c_write(struct i2c_master *master, u8 data)
 109 {
 110         struct lpc_i2c *i2c_data = master->priv;
 111         struct lpc_i2c_regs *i2c = i2c_data->regs;
 112         i2c->CONCLR = CON_STA; /* clear start bit */
 113         i2c->DAT = data;
 114 }
 115
 116 static u8 lpc_i2c_read(struct i2c_master *master)
 117 {
 118         struct lpc_i2c *i2c_data = master->priv;
 119         struct lpc_i2c_regs *i2c = i2c_data->regs;
 120         i2c->CONCLR = CON_STA; /* clear start bit */
 121         return i2c->DAT;
 122 }
 123
 124
 125 int lpc_i2c_register(struct i2c_master *master)
 126 {
 127         struct lpc_i2c *i2c_data = master->priv;
 128         struct lpc_i2c_regs *i2c = i2c_data->regs;
 129
 130         i2c->CONCLR = CON_AA | CON_SI | CON_STA | CON_I2EN;
 131
 132         i2c_irq_data[i2c_data->bus].master = master;
 133         irq_enable(i2c_data->irq);
 134
 135         master->init = lpc_i2c_init;
 136         master->start = lpc_i2c_start;
 137         master->restart = lpc_i2c_restart;
 138         master->stop = lpc_i2c_stop;
 139         master->ack = lpc_i2c_ack;
 140         master->read = lpc_i2c_read;
 141         master->write = lpc_i2c_write;
 142
 143         return 0;
 144 }