1 /*
2 * arch/mips/pmc-sierra/yosemite/i2c-yosemite.c
3 *
4 * Copyright (C) 2003 PMC-Sierra Inc.
5 * Author: Manish Lachwani (lachwani@pmc-sierra.com)
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
11 *
12 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
13 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
14 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
15 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
16 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
17 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
18 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
19 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
20 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
21 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
22 *
23 * You should have received a copy of the GNU General Public License along
24 * with this program; if not, write to the Free Software Foundation, Inc.,
25 * 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27
28 /*
29 * Detailed Description:
30 *
31 * This block implements the I2C interface to the slave devices like the Atmel 24C32
32 * EEPROM and the MAX 1619 Sensors device. The I2C Master interface can be controlled
33 * by the SCMB block. And the SCMB block kicks in only when using the Ethernet Mode of
34 * operation and __not__ the SysAD mode
35 *
36 * The SCMB controls the two modes: MDIO and the I2C. The MDIO mode is used to communicate
37 * with the Quad-PHY from Marvel. The I2C is used to communicate with the I2C slave devices.
38 * It seems that the driver does not explicitly deal with the control of SDA and SCL serial
39 * lines. So, the driver will set the slave address, drive the command and then the data.
40 * The SCMB will then control the two serial lines as required.
41 *
42 * It seems the documents are very unclear abt this. Hence, I took some time out to write
43 * the desciption to have an idea of how the I2C can actually work. Currently, this Linux
44 * driver wont be integrated into the generic Linux I2C framework. And finally, the I2C
45 * interface is also known as the 2BI interface. 2BI means 2-bit interface referring to
46 * SDA and SCL serial lines respectively.
47 *
48 * - Manish Lachwani (12/09/2003)
49 */
50
51 #include "i2c-yosemite.h"
52
53 /*
54 * Poll the I2C interface for the BUSY bit.
55 */
titan_i2c_poll(void)56 static int titan_i2c_poll(void)
57 {
58 int i = 0;
59 unsigned long val = 0;
60
61 for (i = 0; i < TITAN_I2C_MAX_POLL; i++) {
62 val = TITAN_I2C_READ(TITAN_I2C_COMMAND);
63
64 if ( !(val & 0x8000))
65 return 0;
66 }
67
68 return TITAN_I2C_ERR_TIMEOUT;
69 }
70
71 /*
72 * Execute the I2C command
73 */
titan_i2c_xfer(unsigned int slave_addr,titan_i2c_command * cmd,int size,unsigned int * addr)74 int titan_i2c_xfer(unsigned int slave_addr, titan_i2c_command *cmd,
75 int size, unsigned int *addr)
76 {
77 int loop = 0, bytes, i;
78 unsigned int *write_data, data, *read_data;
79 unsigned long reg_val, val;
80
81 write_data = cmd->data;
82 read_data = addr;
83
84 TITAN_I2C_WRITE(TITAN_I2C_SLAVE_ADDRESS, slave_addr);
85
86 if (cmd->type == TITAN_I2C_CMD_WRITE)
87 loop = cmd->write_size;
88 else
89 loop = size;
90
91 while (loop > 0) {
92 if ( (cmd->type == TITAN_I2C_CMD_WRITE) ||
93 (cmd->type == TITAN_I2C_CMD_READ_WRITE) ) {
94
95 reg_val = TITAN_I2C_DATA;
96 for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW; ++i,write_data += 2,
97 reg_val += 4) {
98 if (bytes < cmd->write_size) {
99 data = write_data[0];
100 ++data;
101 }
102
103 if (bytes < cmd->write_size) {
104 data = write_data[1];
105 ++data;
106 }
107
108 TITAN_I2C_WRITE(reg_val, data);
109 }
110 }
111
112 TITAN_I2C_WRITE(TITAN_I2C_COMMAND, (unsigned int)(cmd->type << 13));
113 if (titan_i2c_poll() != TITAN_I2C_ERR_OK)
114 return TITAN_I2C_ERR_TIMEOUT;
115
116 if ( (cmd->type == TITAN_I2C_CMD_READ) ||
117 (cmd->type == TITAN_I2C_CMD_READ_WRITE) ) {
118
119 reg_val = TITAN_I2C_DATA;
120 for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW; ++i,read_data += 2,
121 reg_val += 4) {
122 data = TITAN_I2C_READ(reg_val);
123
124 if (bytes < size) {
125 read_data[0] = data & 0xff;
126 ++bytes;
127 }
128
129 if (bytes < size) {
130 read_data[1] = ((data >> 8) & 0xff);
131 ++bytes;
132 }
133 }
134 }
135
136 loop -= (TITAN_I2C_MAX_WORDS_PER_RW * 2);
137 }
138
139 /*
140 * Read the Interrupt status and then return the appropriate error code
141 */
142
143 val = TITAN_I2C_READ(TITAN_I2C_INTERRUPTS);
144 if (val & 0x0020)
145 return TITAN_I2C_ERR_ARB_LOST;
146
147 if (val & 0x0040)
148 return TITAN_I2C_ERR_NO_RESP;
149
150 if (val & 0x0080)
151 return TITAN_I2C_ERR_DATA_COLLISION;
152
153 return TITAN_I2C_ERR_OK;
154 }
155
156 /*
157 * Init the I2C subsystem of the PMC-Sierra Yosemite board
158 */
titan_i2c_init(titan_i2c_config * config)159 int titan_i2c_init(titan_i2c_config *config)
160 {
161 unsigned int val;
162
163 /*
164 * Reset the SCMB and program into the I2C mode
165 */
166 TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0xA000);
167 TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0x2000);
168
169 /*
170 * Configure the filtera and clka values
171 */
172 val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_A);
173 val |= ( (val & ~(0xF000)) | ( (config->filtera << 12) & 0xF000));
174 val |= ( (val & ~(0x03FF)) | ( config->clka & 0x03FF));
175 TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_A, val);
176
177 /*
178 * Configure the filterb and clkb values
179 */
180 val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_B);
181 val |= ( (val & ~(0xF000)) | ( (config->filterb << 12) & 0xF000));
182 val |= ( (val & ~(0x03FF)) | ( config->clkb & 0x03FF));
183 TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_B, val);
184
185 return TITAN_I2C_ERR_OK;
186 }
187