--- /dev/null
+/*******************************************************************
+*
+* Copyright (c) 2007 by Silicon Motion, Inc. (SMI)
+*
+* All rights are reserved. Reproduction or in part is prohibited
+* without the written consent of the copyright owner.
+*
+* swi2c.c --- SM750/SM718 DDK
+* This file contains the source code for I2C using software
+* implementation.
+*
+*******************************************************************/
+#include "ddk750_help.h"
+#include "ddk750_reg.h"
+#include "ddk750_swi2c.h"
+#include "ddk750_power.h"
+
+
+/*******************************************************************
+ * I2C Software Master Driver:
+ * ===========================
+ * Each i2c cycle is split into 4 sections. Each of these section marks
+ * a point in time where the SCL or SDA may be changed.
+ *
+ * 1 Cycle == | Section I. | Section 2. | Section 3. | Section 4. |
+ * +-------------+-------------+-------------+-------------+
+ * | SCL set LOW |SCL no change| SCL set HIGH|SCL no change|
+ *
+ * ____________ _____________
+ * SCL == XXXX _____________ ____________ /
+ *
+ * I.e. the SCL may only be changed in section 1. and section 3. while
+ * the SDA may only be changed in section 2. and section 4. The table
+ * below gives the changes for these 2 lines in the varios sections.
+ *
+ * Section changes Table:
+ * ======================
+ * blank = no change, L = set bit LOW, H = set bit HIGH
+ *
+ * | 1.| 2.| 3.| 4.|
+ * ---------------+---+---+---+---+
+ * Tx Start SDA | | H | | L |
+ * SCL | L | | H | |
+ * ---------------+---+---+---+---+
+ * Tx Stop SDA | | L | | H |
+ * SCL | L | | H | |
+ * ---------------+---+---+---+---+
+ * Tx bit H SDA | | H | | |
+ * SCL | L | | H | |
+ * ---------------+---+---+---+---+
+ * Tx bit L SDA | | L | | |
+ * SCL | L | | H | |
+ * ---------------+---+---+---+---+
+ *
+ ******************************************************************/
+
+/* GPIO pins used for this I2C. It ranges from 0 to 63. */
+static unsigned char g_i2cClockGPIO = DEFAULT_I2C_SCL;
+static unsigned char g_i2cDataGPIO = DEFAULT_I2C_SDA;
+
+/*
+ * Below is the variable declaration for the GPIO pin register usage
+ * for the i2c Clock and i2c Data.
+ *
+ * Note:
+ * Notice that the GPIO usage for the i2c clock and i2c Data are
+ * separated. This is to make this code flexible enough when
+ * two separate GPIO pins for the clock and data are located
+ * in two different GPIO register set (worst case).
+ */
+
+/* i2c Clock GPIO Register usage */
+static unsigned long g_i2cClkGPIOMuxReg = GPIO_MUX;
+static unsigned long g_i2cClkGPIODataReg = GPIO_DATA;
+static unsigned long g_i2cClkGPIODataDirReg = GPIO_DATA_DIRECTION;
+
+/* i2c Data GPIO Register usage */
+static unsigned long g_i2cDataGPIOMuxReg = GPIO_MUX;
+static unsigned long g_i2cDataGPIODataReg = GPIO_DATA;
+static unsigned long g_i2cDataGPIODataDirReg = GPIO_DATA_DIRECTION;
+
+/*
+ * This function puts a delay between command
+ */
+static void swI2CWait(void)
+{
+ /* find a bug:
+ * peekIO method works well before suspend/resume
+ * but after suspend, peekIO(0x3ce,0x61) & 0x10
+ * always be non-zero,which makes the while loop
+ * never finish.
+ * use non-ultimate for loop below is safe
+ * */
+#if 0
+ /* Change wait algorithm to use PCI bus clock,
+ it's more reliable than counter loop ..
+ write 0x61 to 0x3ce and read from 0x3cf
+ */
+ while(peekIO(0x3ce,0x61) & 0x10);
+#else
+ int i, Temp;
+
+ for(i=0; i<600; i++)
+ {
+ Temp = i;
+ Temp += i;
+ }
+#endif
+}
+
+/*
+ * This function set/reset the SCL GPIO pin
+ *
+ * Parameters:
+ * value - Bit value to set to the SCL or SDA (0 = low, 1 = high)
+ *
+ * Notes:
+ * When setting SCL to high, just set the GPIO as input where the pull up
+ * resistor will pull the signal up. Do not use software to pull up the
+ * signal because the i2c will fail when other device try to drive the
+ * signal due to SM50x will drive the signal to always high.
+ */
+void swI2CSCL(unsigned char value)
+{
+ unsigned long ulGPIOData;
+ unsigned long ulGPIODirection;
+
+ ulGPIODirection = PEEK32(g_i2cClkGPIODataDirReg);
+ if (value) /* High */
+ {
+ /* Set direction as input. This will automatically pull the signal up. */
+ ulGPIODirection &= ~(1 << g_i2cClockGPIO);
+ POKE32(g_i2cClkGPIODataDirReg, ulGPIODirection);
+ }
+ else /* Low */
+ {
+ /* Set the signal down */
+ ulGPIOData = PEEK32(g_i2cClkGPIODataReg);
+ ulGPIOData &= ~(1 << g_i2cClockGPIO);
+ POKE32(g_i2cClkGPIODataReg, ulGPIOData);
+
+ /* Set direction as output */
+ ulGPIODirection |= (1 << g_i2cClockGPIO);
+ POKE32(g_i2cClkGPIODataDirReg, ulGPIODirection);
+ }
+}
+
+/*
+ * This function set/reset the SDA GPIO pin
+ *
+ * Parameters:
+ * value - Bit value to set to the SCL or SDA (0 = low, 1 = high)
+ *
+ * Notes:
+ * When setting SCL to high, just set the GPIO as input where the pull up
+ * resistor will pull the signal up. Do not use software to pull up the
+ * signal because the i2c will fail when other device try to drive the
+ * signal due to SM50x will drive the signal to always high.
+ */
+void swI2CSDA(unsigned char value)
+{
+ unsigned long ulGPIOData;
+ unsigned long ulGPIODirection;
+
+ ulGPIODirection = PEEK32(g_i2cDataGPIODataDirReg);
+ if (value) /* High */
+ {
+ /* Set direction as input. This will automatically pull the signal up. */
+ ulGPIODirection &= ~(1 << g_i2cDataGPIO);
+ POKE32(g_i2cDataGPIODataDirReg, ulGPIODirection);
+ }
+ else /* Low */
+ {
+ /* Set the signal down */
+ ulGPIOData = PEEK32(g_i2cDataGPIODataReg);
+ ulGPIOData &= ~(1 << g_i2cDataGPIO);
+ POKE32(g_i2cDataGPIODataReg, ulGPIOData);
+
+ /* Set direction as output */
+ ulGPIODirection |= (1 << g_i2cDataGPIO);
+ POKE32(g_i2cDataGPIODataDirReg, ulGPIODirection);
+ }
+}
+
+/*
+ * This function read the data from the SDA GPIO pin
+ *
+ * Return Value:
+ * The SDA data bit sent by the Slave
+ */
+static unsigned char swI2CReadSDA(void)
+{
+ unsigned long ulGPIODirection;
+ unsigned long ulGPIOData;
+
+ /* Make sure that the direction is input (High) */
+ ulGPIODirection = PEEK32(g_i2cDataGPIODataDirReg);
+ if ((ulGPIODirection & (1 << g_i2cDataGPIO)) != (~(1 << g_i2cDataGPIO)))
+ {
+ ulGPIODirection &= ~(1 << g_i2cDataGPIO);
+ POKE32(g_i2cDataGPIODataDirReg, ulGPIODirection);
+ }
+
+ /* Now read the SDA line */
+ ulGPIOData = PEEK32(g_i2cDataGPIODataReg);
+ if (ulGPIOData & (1 << g_i2cDataGPIO))
+ return 1;
+ else
+ return 0;
+}
+
+/*
+ * This function sends ACK signal
+ */
+static void swI2CAck(void)
+{
+ return; /* Single byte read is ok without it. */
+}
+
+/*
+ * This function sends the start command to the slave device
+ */
+static void swI2CStart(void)
+{
+ /* Start I2C */
+ swI2CSDA(1);
+ swI2CSCL(1);
+ swI2CSDA(0);
+}
+
+/*
+ * This function sends the stop command to the slave device
+ */
+static void swI2CStop(void)
+{
+ /* Stop the I2C */
+ swI2CSCL(1);
+ swI2CSDA(0);
+ swI2CSDA(1);
+}
+
+/*
+ * This function writes one byte to the slave device
+ *
+ * Parameters:
+ * data - Data to be write to the slave device
+ *
+ * Return Value:
+ * 0 - Success
+ * -1 - Fail to write byte
+ */
+static long swI2CWriteByte(unsigned char data)
+{
+ unsigned char value = data;
+ int i;
+
+ /* Sending the data bit by bit */
+ for (i=0; i<8; i++)
+ {
+ /* Set SCL to low */
+ swI2CSCL(0);
+
+ /* Send data bit */
+ if ((value & 0x80) != 0)
+ swI2CSDA(1);
+ else
+ swI2CSDA(0);
+
+ swI2CWait();
+
+ /* Toggle clk line to one */
+ swI2CSCL(1);
+ swI2CWait();
+
+ /* Shift byte to be sent */
+ value = value << 1;
+ }
+
+ /* Set the SCL Low and SDA High (prepare to get input) */
+ swI2CSCL(0);
+ swI2CSDA(1);
+
+ /* Set the SCL High for ack */
+ swI2CWait();
+ swI2CSCL(1);
+ swI2CWait();
+
+ /* Read SDA, until SDA==0 */
+ for(i=0; i<0xff; i++)
+ {
+ if (!swI2CReadSDA())
+ break;
+
+ swI2CSCL(0);
+ swI2CWait();
+ swI2CSCL(1);
+ swI2CWait();
+ }
+
+ /* Set the SCL Low and SDA High */
+ swI2CSCL(0);
+ swI2CSDA(1);
+
+ if (i<0xff)
+ return 0;
+ else
+ return -1;
+}
+
+/*
+ * This function reads one byte from the slave device
+ *
+ * Parameters:
+ * ack - Flag to indicate either to send the acknowledge
+ * message to the slave device or not
+ *
+ * Return Value:
+ * One byte data read from the Slave device
+ */
+static unsigned char swI2CReadByte(unsigned char ack)
+{
+ int i;
+ unsigned char data = 0;
+
+ for(i=7; i>=0; i--)
+ {
+ /* Set the SCL to Low and SDA to High (Input) */
+ swI2CSCL(0);
+ swI2CSDA(1);
+ swI2CWait();
+
+ /* Set the SCL High */
+ swI2CSCL(1);
+ swI2CWait();
+
+ /* Read data bits from SDA */
+ data |= (swI2CReadSDA() << i);
+ }
+
+ if (ack)
+ swI2CAck();
+
+ /* Set the SCL Low and SDA High */
+ swI2CSCL(0);
+ swI2CSDA(1);
+
+ return data;
+}
+
+/*
+ * This function initializes GPIO port for SW I2C communication.
+ *
+ * Parameters:
+ * i2cClkGPIO - The GPIO pin to be used as i2c SCL
+ * i2cDataGPIO - The GPIO pin to be used as i2c SDA
+ *
+ * Return Value:
+ * -1 - Fail to initialize the i2c
+ * 0 - Success
+ */
+static long swI2CInit_SM750LE(unsigned char i2cClkGPIO,
+ unsigned char i2cDataGPIO)
+{
+ int i;
+
+ /* Initialize the GPIO pin for the i2c Clock Register */
+ g_i2cClkGPIODataReg = GPIO_DATA_SM750LE;
+ g_i2cClkGPIODataDirReg = GPIO_DATA_DIRECTION_SM750LE;
+
+ /* Initialize the Clock GPIO Offset */
+ g_i2cClockGPIO = i2cClkGPIO;
+
+ /* Initialize the GPIO pin for the i2c Data Register */
+ g_i2cDataGPIODataReg = GPIO_DATA_SM750LE;
+ g_i2cDataGPIODataDirReg = GPIO_DATA_DIRECTION_SM750LE;
+
+ /* Initialize the Data GPIO Offset */
+ g_i2cDataGPIO = i2cDataGPIO;
+
+ /* Note that SM750LE don't have GPIO MUX and power is always on */
+
+ /* Clear the i2c lines. */
+ for(i=0; i<9; i++)
+ swI2CStop();
+
+ return 0;
+}
+
+/*
+ * This function initializes the i2c attributes and bus
+ *
+ * Parameters:
+ * i2cClkGPIO - The GPIO pin to be used as i2c SCL
+ * i2cDataGPIO - The GPIO pin to be used as i2c SDA
+ *
+ * Return Value:
+ * -1 - Fail to initialize the i2c
+ * 0 - Success
+ */
+long swI2CInit(
+ unsigned char i2cClkGPIO,
+ unsigned char i2cDataGPIO
+)
+{
+ int i;
+
+ /* Return 0 if the GPIO pins to be used is out of range. The range is only from [0..63] */
+ if ((i2cClkGPIO > 31) || (i2cDataGPIO > 31))
+ return -1;
+
+ if (getChipType() == SM750LE)
+ return swI2CInit_SM750LE(i2cClkGPIO, i2cDataGPIO);
+
+ /* Initialize the GPIO pin for the i2c Clock Register */
+ g_i2cClkGPIOMuxReg = GPIO_MUX;
+ g_i2cClkGPIODataReg = GPIO_DATA;
+ g_i2cClkGPIODataDirReg = GPIO_DATA_DIRECTION;
+
+ /* Initialize the Clock GPIO Offset */
+ g_i2cClockGPIO = i2cClkGPIO;
+
+ /* Initialize the GPIO pin for the i2c Data Register */
+ g_i2cDataGPIOMuxReg = GPIO_MUX;
+ g_i2cDataGPIODataReg = GPIO_DATA;
+ g_i2cDataGPIODataDirReg = GPIO_DATA_DIRECTION;
+
+ /* Initialize the Data GPIO Offset */
+ g_i2cDataGPIO = i2cDataGPIO;
+
+ /* Enable the GPIO pins for the i2c Clock and Data (GPIO MUX) */
+ POKE32(g_i2cClkGPIOMuxReg,
+ PEEK32(g_i2cClkGPIOMuxReg) & ~(1 << g_i2cClockGPIO));
+ POKE32(g_i2cDataGPIOMuxReg,
+ PEEK32(g_i2cDataGPIOMuxReg) & ~(1 << g_i2cDataGPIO));
+
+ /* Enable GPIO power */
+ enableGPIO(1);
+
+ /* Clear the i2c lines. */
+ for(i=0; i<9; i++)
+ swI2CStop();
+
+ return 0;
+}
+
+/*
+ * This function reads the slave device's register
+ *
+ * Parameters:
+ * deviceAddress - i2c Slave device address which register
+ * to be read from
+ * registerIndex - Slave device's register to be read
+ *
+ * Return Value:
+ * Register value
+ */
+unsigned char swI2CReadReg(
+ unsigned char deviceAddress,
+ unsigned char registerIndex
+)
+{
+ unsigned char data;
+
+ /* Send the Start signal */
+ swI2CStart();
+
+ /* Send the device address */
+ swI2CWriteByte(deviceAddress);
+
+ /* Send the register index */
+ swI2CWriteByte(registerIndex);
+
+ /* Get the bus again and get the data from the device read address */
+ swI2CStart();
+ swI2CWriteByte(deviceAddress + 1);
+ data = swI2CReadByte(1);
+
+ /* Stop swI2C and release the bus */
+ swI2CStop();
+
+ return data;
+}
+
+/*
+ * This function writes a value to the slave device's register
+ *
+ * Parameters:
+ * deviceAddress - i2c Slave device address which register
+ * to be written
+ * registerIndex - Slave device's register to be written
+ * data - Data to be written to the register
+ *
+ * Result:
+ * 0 - Success
+ * -1 - Fail
+ */
+long swI2CWriteReg(
+ unsigned char deviceAddress,
+ unsigned char registerIndex,
+ unsigned char data
+)
+{
+ long returnValue = 0;
+
+ /* Send the Start signal */
+ swI2CStart();
+
+ /* Send the device address and read the data. All should return success
+ in order for the writing processed to be successful
+ */
+ if ((swI2CWriteByte(deviceAddress) != 0) ||
+ (swI2CWriteByte(registerIndex) != 0) ||
+ (swI2CWriteByte(data) != 0))
+ {
+ returnValue = -1;
+ }
+
+ /* Stop i2c and release the bus */
+ swI2CStop();
+
+ return returnValue;
+}
Code Review / kvmfornfv.git / blobdiff