189 строки
5.4 KiB
C
189 строки
5.4 KiB
C
/*
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* Copyright (C) 2003 PMC-Sierra Inc.
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* Author: Manish Lachwani (lachwani@pmc-sierra.com)
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
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* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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* Detailed Description:
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*
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* This block implements the I2C interface to the slave devices like the
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* Atmel 24C32 EEPROM and the MAX 1619 Sensors device. The I2C Master interface
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* can be controlled by the SCMB block. And the SCMB block kicks in only when
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* using the Ethernet Mode of operation and __not__ the SysAD mode
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*
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* The SCMB controls the two modes: MDIO and the I2C. The MDIO mode is used to
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* communicate with the Quad-PHY from Marvel. The I2C is used to communicate
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* with the I2C slave devices. It seems that the driver does not explicitly
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* deal with the control of SDA and SCL serial lines. So, the driver will set
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* the slave address, drive the command and then the data. The SCMB will then
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* control the two serial lines as required.
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*
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* It seems the documents are very unclear abt this. Hence, I took some time
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* out to write the desciption to have an idea of how the I2C can actually
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* work. Currently, this Linux driver wont be integrated into the generic Linux
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* I2C framework. And finally, the I2C interface is also known as the 2BI
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* interface. 2BI means 2-bit interface referring to SDA and SCL serial lines
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* respectively.
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*
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* - Manish Lachwani (12/09/2003)
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*/
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#include "i2c-yosemite.h"
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/*
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* Poll the I2C interface for the BUSY bit.
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*/
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static int titan_i2c_poll(void)
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{
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int i = 0;
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unsigned long val = 0;
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for (i = 0; i < TITAN_I2C_MAX_POLL; i++) {
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val = TITAN_I2C_READ(TITAN_I2C_COMMAND);
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if (!(val & 0x8000))
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return 0;
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}
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return TITAN_I2C_ERR_TIMEOUT;
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}
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/*
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* Execute the I2C command
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*/
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int titan_i2c_xfer(unsigned int slave_addr, titan_i2c_command * cmd,
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int size, unsigned int *addr)
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{
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int loop = 0, bytes, i;
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unsigned int *write_data, data, *read_data;
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unsigned long reg_val, val;
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write_data = cmd->data;
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read_data = addr;
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TITAN_I2C_WRITE(TITAN_I2C_SLAVE_ADDRESS, slave_addr);
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if (cmd->type == TITAN_I2C_CMD_WRITE)
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loop = cmd->write_size;
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else
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loop = size;
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while (loop > 0) {
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if ((cmd->type == TITAN_I2C_CMD_WRITE) ||
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(cmd->type == TITAN_I2C_CMD_READ_WRITE)) {
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reg_val = TITAN_I2C_DATA;
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for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW;
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++i, write_data += 2, reg_val += 4) {
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if (bytes < cmd->write_size) {
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data = write_data[0];
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++data;
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}
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if (bytes < cmd->write_size) {
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data = write_data[1];
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++data;
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}
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TITAN_I2C_WRITE(reg_val, data);
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}
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}
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TITAN_I2C_WRITE(TITAN_I2C_COMMAND,
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(unsigned int) (cmd->type << 13));
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if (titan_i2c_poll() != TITAN_I2C_ERR_OK)
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return TITAN_I2C_ERR_TIMEOUT;
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if ((cmd->type == TITAN_I2C_CMD_READ) ||
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(cmd->type == TITAN_I2C_CMD_READ_WRITE)) {
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reg_val = TITAN_I2C_DATA;
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for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW;
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++i, read_data += 2, reg_val += 4) {
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data = TITAN_I2C_READ(reg_val);
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if (bytes < size) {
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read_data[0] = data & 0xff;
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++bytes;
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}
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if (bytes < size) {
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read_data[1] =
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((data >> 8) & 0xff);
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++bytes;
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}
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}
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}
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loop -= (TITAN_I2C_MAX_WORDS_PER_RW * 2);
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}
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/*
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* Read the Interrupt status and then return the appropriate error code
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*/
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val = TITAN_I2C_READ(TITAN_I2C_INTERRUPTS);
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if (val & 0x0020)
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return TITAN_I2C_ERR_ARB_LOST;
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if (val & 0x0040)
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return TITAN_I2C_ERR_NO_RESP;
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if (val & 0x0080)
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return TITAN_I2C_ERR_DATA_COLLISION;
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return TITAN_I2C_ERR_OK;
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}
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/*
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* Init the I2C subsystem of the PMC-Sierra Yosemite board
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*/
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int titan_i2c_init(titan_i2c_config * config)
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{
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unsigned int val;
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/*
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* Reset the SCMB and program into the I2C mode
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*/
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TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0xA000);
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TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0x2000);
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/*
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* Configure the filtera and clka values
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*/
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val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_A);
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val |= ((val & ~(0xF000)) | ((config->filtera << 12) & 0xF000));
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val |= ((val & ~(0x03FF)) | (config->clka & 0x03FF));
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TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_A, val);
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/*
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* Configure the filterb and clkb values
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*/
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val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_B);
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val |= ((val & ~(0xF000)) | ((config->filterb << 12) & 0xF000));
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val |= ((val & ~(0x03FF)) | (config->clkb & 0x03FF));
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TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_B, val);
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return TITAN_I2C_ERR_OK;
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}
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