1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Coral-P(A)/Lime I2C adapter driver 4 * 5 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de> 6 */ 7 8 #include <linux/fb.h> 9 #include <linux/i2c.h> 10 #include <linux/io.h> 11 #include <linux/delay.h> 12 13 #include "mb862xxfb.h" 14 #include "mb862xx_reg.h" 15 16 static int mb862xx_i2c_wait_event(struct i2c_adapter *adap) 17 { 18 struct mb862xxfb_par *par = adap->algo_data; 19 u32 reg; 20 21 do { 22 udelay(10); 23 reg = inreg(i2c, GC_I2C_BCR); 24 if (reg & (I2C_INT | I2C_BER)) 25 break; 26 } while (1); 27 28 return (reg & I2C_BER) ? 0 : 1; 29 } 30 31 static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr) 32 { 33 struct mb862xxfb_par *par = adap->algo_data; 34 35 outreg(i2c, GC_I2C_DAR, addr); 36 outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE); 37 outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START); 38 if (!mb862xx_i2c_wait_event(adap)) 39 return -EIO; 40 par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); 41 return par->i2c_rs; 42 } 43 44 static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte) 45 { 46 struct mb862xxfb_par *par = adap->algo_data; 47 48 outreg(i2c, GC_I2C_DAR, byte); 49 outreg(i2c, GC_I2C_BCR, I2C_START); 50 if (!mb862xx_i2c_wait_event(adap)) 51 return -EIO; 52 return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); 53 } 54 55 static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last) 56 { 57 struct mb862xxfb_par *par = adap->algo_data; 58 59 outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK)); 60 if (!mb862xx_i2c_wait_event(adap)) 61 return 0; 62 *byte = inreg(i2c, GC_I2C_DAR); 63 return 1; 64 } 65 66 static void mb862xx_i2c_stop(struct i2c_adapter *adap) 67 { 68 struct mb862xxfb_par *par = adap->algo_data; 69 70 outreg(i2c, GC_I2C_BCR, I2C_STOP); 71 outreg(i2c, GC_I2C_CCR, I2C_DISABLE); 72 par->i2c_rs = 0; 73 } 74 75 static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m) 76 { 77 int i, ret = 0; 78 int last = m->len - 1; 79 80 for (i = 0; i < m->len; i++) { 81 if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) { 82 ret = -EIO; 83 break; 84 } 85 } 86 return ret; 87 } 88 89 static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m) 90 { 91 int i, ret = 0; 92 93 for (i = 0; i < m->len; i++) { 94 if (!mb862xx_i2c_write_byte(adap, m->buf[i])) { 95 ret = -EIO; 96 break; 97 } 98 } 99 return ret; 100 } 101 102 static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 103 int num) 104 { 105 struct mb862xxfb_par *par = adap->algo_data; 106 struct i2c_msg *m; 107 int addr; 108 int i = 0, err = 0; 109 110 dev_dbg(par->dev, "%s: %d msgs\n", __func__, num); 111 112 for (i = 0; i < num; i++) { 113 m = &msgs[i]; 114 if (!m->len) { 115 dev_dbg(par->dev, "%s: null msgs\n", __func__); 116 continue; 117 } 118 addr = m->addr; 119 if (m->flags & I2C_M_RD) 120 addr |= 1; 121 122 err = mb862xx_i2c_do_address(adap, addr); 123 if (err < 0) 124 break; 125 if (m->flags & I2C_M_RD) 126 err = mb862xx_i2c_read(adap, m); 127 else 128 err = mb862xx_i2c_write(adap, m); 129 } 130 131 if (i) 132 mb862xx_i2c_stop(adap); 133 134 return (err < 0) ? err : i; 135 } 136 137 static u32 mb862xx_func(struct i2c_adapter *adap) 138 { 139 return I2C_FUNC_SMBUS_BYTE_DATA; 140 } 141 142 static const struct i2c_algorithm mb862xx_algo = { 143 .master_xfer = mb862xx_xfer, 144 .functionality = mb862xx_func, 145 }; 146 147 static struct i2c_adapter mb862xx_i2c_adapter = { 148 .name = "MB862xx I2C adapter", 149 .algo = &mb862xx_algo, 150 .owner = THIS_MODULE, 151 }; 152 153 int mb862xx_i2c_init(struct mb862xxfb_par *par) 154 { 155 mb862xx_i2c_adapter.algo_data = par; 156 par->adap = &mb862xx_i2c_adapter; 157 158 return i2c_add_adapter(par->adap); 159 } 160 161 void mb862xx_i2c_exit(struct mb862xxfb_par *par) 162 { 163 if (par->adap) { 164 i2c_del_adapter(par->adap); 165 par->adap = NULL; 166 } 167 } 168