patch-2.4.25 linux-2.4.25/arch/mips/pmc-sierra/yosemite/i2c-yosemite.c

• Lines: 187
• Date: 2004-02-18 05:36:30.000000000 -0800
• Orig file: linux-2.4.24/arch/mips/pmc-sierra/yosemite/i2c-yosemite.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/arch/mips/pmc-sierra/yosemite/i2c-yosemite.c linux-2.4.25/arch/mips/pmc-sierra/yosemite/i2c-yosemite.c
@@ -0,0 +1,186 @@
+/*
+ *  arch/mips/pmc-sierra/yosemite/i2c-yosemite.c
+ *
+ *  Copyright (C) 2003 PMC-Sierra Inc.
+ *  Author: Manish Lachwani (lachwani@pmc-sierra.com)
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
+ *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+ *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
+ *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  You should have received a copy of the  GNU General Public License along
+ *  with this program; if not, write  to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * Detailed Description:
+ *
+ * This block implements the I2C interface to the slave devices like the Atmel 24C32
+ * EEPROM and the MAX 1619 Sensors device. The I2C Master interface can be controlled
+ * by the SCMB block. And the SCMB block kicks in only when using the Ethernet Mode of
+ * operation and __not__ the SysAD mode
+ *
+ * The SCMB controls the two modes: MDIO and the I2C. The MDIO mode is used to communicate
+ * with the Quad-PHY from Marvel. The I2C is used to communicate with the I2C slave devices.
+ * It seems that the driver does not explicitly deal with the control of SDA and SCL serial
+ * lines. So, the driver will set the slave address, drive the command and then the data. 
+ * The SCMB will then control the two serial lines as required. 
+ *
+ * It seems the documents are very unclear abt this. Hence, I took some time out to write
+ * the desciption to have an idea of how the I2C can actually work. Currently, this Linux 
+ * driver wont be integrated into the generic Linux I2C framework. And finally, the I2C 
+ * interface is also known as the 2BI interface. 2BI means 2-bit interface referring to
+ * SDA and SCL serial lines respectively.
+ *
+ * - Manish Lachwani (12/09/2003)
+ */
+
+#include "i2c-yosemite.h"
+
+/*
+ * Poll the I2C interface for the BUSY bit. 
+ */
+static int titan_i2c_poll(void)
+{
+	int		i = 0;
+	unsigned long	val = 0;
+
+	for (i = 0; i < TITAN_I2C_MAX_POLL; i++) {
+		val = TITAN_I2C_READ(TITAN_I2C_COMMAND);
+
+		if ( !(val & 0x8000))
+			return 0;
+	}
+
+	return TITAN_I2C_ERR_TIMEOUT;
+}
+
+/*
+ * Execute the I2C command
+ */
+int titan_i2c_xfer(unsigned int slave_addr, titan_i2c_command *cmd, 
+						int size, unsigned int *addr)
+{
+	int		loop = 0, bytes, i;
+	unsigned int	*write_data, data, *read_data;
+	unsigned long	reg_val, val;
+
+	write_data = cmd->data;
+	read_data = addr;
+
+	TITAN_I2C_WRITE(TITAN_I2C_SLAVE_ADDRESS, slave_addr);
+
+	if (cmd->type == TITAN_I2C_CMD_WRITE) 
+		loop = cmd->write_size;
+	else
+		loop = size;
+
+	while (loop > 0) {
+		if ( (cmd->type == TITAN_I2C_CMD_WRITE)  || 
+			(cmd->type == TITAN_I2C_CMD_READ_WRITE) ) {
+			
+			reg_val = TITAN_I2C_DATA;
+			for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW; ++i,write_data += 2,
+								reg_val += 4) {
+				if (bytes < cmd->write_size) {
+					data = write_data[0];
+					++data;
+				}
+
+				if (bytes < cmd->write_size) {
+					data = write_data[1];
+					++data;
+				}
+
+				TITAN_I2C_WRITE(reg_val, data);
+			}
+		}
+
+		TITAN_I2C_WRITE(TITAN_I2C_COMMAND, (unsigned int)(cmd->type << 13));
+		if (titan_i2c_poll() != TITAN_I2C_ERR_OK)
+			return TITAN_I2C_ERR_TIMEOUT;
+
+		if ( (cmd->type == TITAN_I2C_CMD_READ)  ||
+			(cmd->type == TITAN_I2C_CMD_READ_WRITE) ) {
+			
+			reg_val = TITAN_I2C_DATA;
+			for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW; ++i,read_data += 2,
+								reg_val += 4) {
+				data = TITAN_I2C_READ(reg_val);
+				
+				if (bytes < size) {
+					read_data[0] = data & 0xff;
+					++bytes;
+				}
+
+				if (bytes < size) {
+					read_data[1] = ((data >> 8) & 0xff);
+					++bytes;
+				}
+			}
+		}
+
+		loop -= (TITAN_I2C_MAX_WORDS_PER_RW * 2);
+	}
+						
+	/*
+	 * Read the Interrupt status and then return the appropriate error code 
+	 */
+
+	val = TITAN_I2C_READ(TITAN_I2C_INTERRUPTS);
+	if (val & 0x0020)
+		return TITAN_I2C_ERR_ARB_LOST;
+
+	if (val & 0x0040)
+		return TITAN_I2C_ERR_NO_RESP;
+
+	if (val & 0x0080)
+		return TITAN_I2C_ERR_DATA_COLLISION;
+
+	return TITAN_I2C_ERR_OK;
+}
+
+/*
+ * Init the I2C subsystem of the PMC-Sierra Yosemite board
+ */
+int titan_i2c_init(titan_i2c_config *config)
+{
+	unsigned int	val;
+
+	/*
+	 * Reset the SCMB and program into the I2C mode
+	 */
+	TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0xA000);
+	TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0x2000);
+
+	/*
+	 * Configure the filtera and clka values
+	 */
+	val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_A);
+	val |= ( (val & ~(0xF000)) | ( (config->filtera << 12) & 0xF000));
+	val |= ( (val & ~(0x03FF)) | ( config->clka & 0x03FF));
+	TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_A, val);
+
+	/*
+	 * Configure the filterb and clkb values
+	 */
+	val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_B);
+	val |= ( (val & ~(0xF000)) | ( (config->filterb << 12) & 0xF000));
+	val |= ( (val & ~(0x03FF)) | ( config->clkb & 0x03FF));
+	TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_B, val);
+
+	return TITAN_I2C_ERR_OK;
+}