1 /* 2 * Coral-P(A)/Lime I2C adapter driver 3 * 4 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 */ 11 12 #include <linux/fb.h> 13 #include <linux/i2c.h> 14 #include <linux/io.h> 15 #include <linux/delay.h> 16 #include <linux/export.h> 17 18 #include "mb862xxfb.h" 19 #include "mb862xx_reg.h" 20 21 static int mb862xx_i2c_wait_event(struct i2c_adapter *adap) 22 { 23 struct mb862xxfb_par *par = adap->algo_data; 24 u32 reg; 25 26 do { 27 udelay(10); 28 reg = inreg(i2c, GC_I2C_BCR); 29 if (reg & (I2C_INT | I2C_BER)) 30 break; 31 } while (1); 32 33 return (reg & I2C_BER) ? 0 : 1; 34 } 35 36 static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr) 37 { 38 struct mb862xxfb_par *par = adap->algo_data; 39 40 outreg(i2c, GC_I2C_DAR, addr); 41 outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE); 42 outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START); 43 if (!mb862xx_i2c_wait_event(adap)) 44 return -EIO; 45 par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); 46 return par->i2c_rs; 47 } 48 49 static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte) 50 { 51 struct mb862xxfb_par *par = adap->algo_data; 52 53 outreg(i2c, GC_I2C_DAR, byte); 54 outreg(i2c, GC_I2C_BCR, I2C_START); 55 if (!mb862xx_i2c_wait_event(adap)) 56 return -EIO; 57 return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); 58 } 59 60 static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last) 61 { 62 struct mb862xxfb_par *par = adap->algo_data; 63 64 outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK)); 65 if (!mb862xx_i2c_wait_event(adap)) 66 return 0; 67 *byte = inreg(i2c, GC_I2C_DAR); 68 return 1; 69 } 70 71 static void mb862xx_i2c_stop(struct i2c_adapter *adap) 72 { 73 struct mb862xxfb_par *par = adap->algo_data; 74 75 outreg(i2c, GC_I2C_BCR, I2C_STOP); 76 outreg(i2c, GC_I2C_CCR, I2C_DISABLE); 77 par->i2c_rs = 0; 78 } 79 80 static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m) 81 { 82 int i, ret = 0; 83 int last = m->len - 1; 84 85 for (i = 0; i < m->len; i++) { 86 if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) { 87 ret = -EIO; 88 break; 89 } 90 } 91 return ret; 92 } 93 94 static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m) 95 { 96 int i, ret = 0; 97 98 for (i = 0; i < m->len; i++) { 99 if (!mb862xx_i2c_write_byte(adap, m->buf[i])) { 100 ret = -EIO; 101 break; 102 } 103 } 104 return ret; 105 } 106 107 static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 108 int num) 109 { 110 struct mb862xxfb_par *par = adap->algo_data; 111 struct i2c_msg *m; 112 int addr; 113 int i = 0, err = 0; 114 115 dev_dbg(par->dev, "%s: %d msgs\n", __func__, num); 116 117 for (i = 0; i < num; i++) { 118 m = &msgs[i]; 119 if (!m->len) { 120 dev_dbg(par->dev, "%s: null msgs\n", __func__); 121 continue; 122 } 123 addr = m->addr; 124 if (m->flags & I2C_M_RD) 125 addr |= 1; 126 127 err = mb862xx_i2c_do_address(adap, addr); 128 if (err < 0) 129 break; 130 if (m->flags & I2C_M_RD) 131 err = mb862xx_i2c_read(adap, m); 132 else 133 err = mb862xx_i2c_write(adap, m); 134 } 135 136 if (i) 137 mb862xx_i2c_stop(adap); 138 139 return (err < 0) ? err : i; 140 } 141 142 static u32 mb862xx_func(struct i2c_adapter *adap) 143 { 144 return I2C_FUNC_SMBUS_BYTE_DATA; 145 } 146 147 static const struct i2c_algorithm mb862xx_algo = { 148 .master_xfer = mb862xx_xfer, 149 .functionality = mb862xx_func, 150 }; 151 152 static struct i2c_adapter mb862xx_i2c_adapter = { 153 .name = "MB862xx I2C adapter", 154 .algo = &mb862xx_algo, 155 .owner = THIS_MODULE, 156 }; 157 158 int mb862xx_i2c_init(struct mb862xxfb_par *par) 159 { 160 int ret; 161 162 mb862xx_i2c_adapter.algo_data = par; 163 par->adap = &mb862xx_i2c_adapter; 164 165 ret = i2c_add_adapter(par->adap); 166 if (ret < 0) { 167 dev_err(par->dev, "failed to add %s\n", 168 mb862xx_i2c_adapter.name); 169 } 170 return ret; 171 } 172 173 void mb862xx_i2c_exit(struct mb862xxfb_par *par) 174 { 175 if (par->adap) { 176 i2c_del_adapter(par->adap); 177 par->adap = NULL; 178 } 179 } 180