drivers/staging/dt3155/dt3155_io.c

   1 /*
   2  * Copyright 1996,2002,2005 Gregory D. Hager, Alfred A. Rizzi, Noah J. Cowan,
   3  *                          Jason Lapenta, Scott Smedley
   4  *
   5  * This file is part of the DT3155 Device Driver.
   6  *
   7  * The DT3155 Device Driver is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or (at your
  10  * option) any later version.
  11  *
  12  * The DT3155 Device Driver is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  15  * Public License for more details.
  16  */
  17
  18 /*
  19  * This file provides some basic register io routines.  It is modified from
  20  * demo code provided by Data Translations.
  21  */
  22
  23 #include <linux/delay.h>
  24 #include <linux/io.h>
  25
  26 #include "dt3155.h"
  27 #include "dt3155_io.h"
  28 #include "dt3155_drv.h"
  29
  30
  31 /****** local copies of board's 32 bit registers ******/
  32 u32 even_dma_start_r;   /*  bit 0 should always be 0 */
  33 u32 odd_dma_start_r;    /*               .. */
  34 u32 even_dma_stride_r;  /*  bits 0&1 should always be 0 */
  35 u32 odd_dma_stride_r;   /*               .. */
  36
  37 CSR1_R                  csr1_r;
  38 INT_CSR_R               int_csr_r;
  39
  40 IIC_CSR1_R              iic_csr1_r;
  41 IIC_CSR2_R              iic_csr2_r;
  42
  43
  44
  45 /******** local copies of board's 8 bit I2C registers ******/
  46 I2C_CSR2 i2c_csr2;
  47 I2C_EVEN_CSR i2c_even_csr;
  48 I2C_ODD_CSR i2c_odd_csr;
  49
  50 /*
  51  * wait_ibsyclr()
  52  *
  53  * This function handles read/write timing and r/w timeout error
  54  */
  55 static int wait_ibsyclr(void __iomem *mmio)
  56 {
  57         /* wait 100 microseconds */
  58         udelay(100L);
  59         /* __delay(loops_per_sec/10000); */
  60
  61         iic_csr2_r.reg = readl(mmio + IIC_CSR2);
  62         if (iic_csr2_r.fld.NEW_CYCLE) {
  63                 /* if NEW_CYCLE didn't clear */
  64                 /* TIMEOUT ERROR */
  65                 dt3155_errno = DT_ERR_I2C_TIMEOUT;
  66                 return -ETIMEDOUT;
  67         }
  68
  69         return 0;       /* no error */
  70 }
  71
  72 /*
  73  * WriteI2C()
  74  *
  75  * This function handles writing to 8-bit DT3155 registers
  76  *
  77  * 1st parameter is pointer to 32-bit register base address
  78  * 2nd parameter is reg. index;
  79  * 3rd is value to be written
  80  */
  81 int WriteI2C(void __iomem *mmio, u_short wIregIndex, u8 byVal)
  82 {
  83         /* read 32 bit IIC_CSR2 register data into union */
  84
  85         iic_csr2_r.reg = readl(mmio + IIC_CSR2);
  86
  87         /* for write operation */
  88         iic_csr2_r.fld.DIR_RD      = 0;
  89         /* I2C address of I2C register: */
  90         iic_csr2_r.fld.DIR_ADDR    = wIregIndex;
  91         /* 8 bit data to be written to I2C reg */
  92         iic_csr2_r.fld.DIR_WR_DATA = byVal;
  93         /* will start a direct I2C cycle: */
  94         iic_csr2_r.fld.NEW_CYCLE   = 1;
  95
  96         /* xfer union data into 32 bit IIC_CSR2 register */
  97         writel(iic_csr2_r.reg, mmio + IIC_CSR2);
  98
  99         /* wait for IIC cycle to finish */
 100         return wait_ibsyclr(mmio);
 101 }
 102
 103 /*
 104  * ReadI2C()
 105  *
 106  * This function handles reading from 8-bit DT3155 registers
 107  *
 108  * 1st parameter is pointer to 32-bit register base address
 109  * 2nd parameter is reg. index;
 110  * 3rd is adrs of value to be read
 111  */
 112 int ReadI2C(void __iomem *mmio, u_short wIregIndex, u8 *byVal)
 113 {
 114         int writestat;  /* status for return */
 115
 116         /*  read 32 bit IIC_CSR2 register data into union */
 117         iic_csr2_r.reg = readl(mmio + IIC_CSR2);
 118
 119         /*  for read operation */
 120         iic_csr2_r.fld.DIR_RD     = 1;
 121
 122         /*  I2C address of I2C register: */
 123         iic_csr2_r.fld.DIR_ADDR   = wIregIndex;
 124
 125         /*  will start a direct I2C cycle: */
 126         iic_csr2_r.fld.NEW_CYCLE  = 1;
 127
 128         /*  xfer union's data into 32 bit IIC_CSR2 register */
 129         writel(iic_csr2_r.reg, mmio + IIC_CSR2);
 130
 131         /* wait for IIC cycle to finish */
 132         writestat = wait_ibsyclr(mmio);
 133
 134         /* Next 2 commands read 32 bit IIC_CSR1 register's data into union */
 135         /* first read data is in IIC_CSR1 */
 136         iic_csr1_r.reg = readl(mmio + IIC_CSR1);
 137
 138         /* now get data u8 out of register */
 139         *byVal = (u8) iic_csr1_r.fld.RD_DATA;
 140
 141         return writestat;
 142 }