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 #include <linux/export.h> 13 14 #include "mb862xxfb.h" 15 #include "mb862xx_reg.h" 16 17 static int mb862xx_i2c_wait_event(struct i2c_adapter *adap) 18 { 19 struct mb862xxfb_par *par = adap->algo_data; 20 u32 reg; 21 22 do { 23 udelay(10); 24 reg = inreg(i2c, GC_I2C_BCR); 25 if (reg & (I2C_INT | I2C_BER)) 26 break; 27 } while (1); 28 29 return (reg & I2C_BER) ? 0 : 1; 30 } 31 32 static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr) 33 { 34 struct mb862xxfb_par *par = adap->algo_data; 35 36 outreg(i2c, GC_I2C_DAR, addr); 37 outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE); 38 outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START); 39 if (!mb862xx_i2c_wait_event(adap)) 40 return -EIO; 41 par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); 42 return par->i2c_rs; 43 } 44 45 static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte) 46 { 47 struct mb862xxfb_par *par = adap->algo_data; 48 49 outreg(i2c, GC_I2C_DAR, byte); 50 outreg(i2c, GC_I2C_BCR, I2C_START); 51 if (!mb862xx_i2c_wait_event(adap)) 52 return -EIO; 53 return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); 54 } 55 56 static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last) 57 { 58 struct mb862xxfb_par *par = adap->algo_data; 59 60 outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK)); 61 if (!mb862xx_i2c_wait_event(adap)) 62 return 0; 63 *byte = inreg(i2c, GC_I2C_DAR); 64 return 1; 65 } 66 67 static void mb862xx_i2c_stop(struct i2c_adapter *adap) 68 { 69 struct mb862xxfb_par *par = adap->algo_data; 70 71 outreg(i2c, GC_I2C_BCR, I2C_STOP); 72 outreg(i2c, GC_I2C_CCR, I2C_DISABLE); 73 par->i2c_rs = 0; 74 } 75 76 static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m) 77 { 78 int i, ret = 0; 79 int last = m->len - 1; 80 81 for (i = 0; i < m->len; i++) { 82 if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) { 83 ret = -EIO; 84 break; 85 } 86 } 87 return ret; 88 } 89 90 static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m) 91 { 92 int i, ret = 0; 93 94 for (i = 0; i < m->len; i++) { 95 if (!mb862xx_i2c_write_byte(adap, m->buf[i])) { 96 ret = -EIO; 97 break; 98 } 99 } 100 return ret; 101 } 102 103 static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 104 int num) 105 { 106 struct mb862xxfb_par *par = adap->algo_data; 107 struct i2c_msg *m; 108 int addr; 109 int i = 0, err = 0; 110 111 dev_dbg(par->dev, "%s: %d msgs\n", __func__, num); 112 113 for (i = 0; i < num; i++) { 114 m = &msgs[i]; 115 if (!m->len) { 116 dev_dbg(par->dev, "%s: null msgs\n", __func__); 117 continue; 118 } 119 addr = m->addr; 120 if (m->flags & I2C_M_RD) 121 addr |= 1; 122 123 err = mb862xx_i2c_do_address(adap, addr); 124 if (err < 0) 125 break; 126 if (m->flags & I2C_M_RD) 127 err = mb862xx_i2c_read(adap, m); 128 else 129 err = mb862xx_i2c_write(adap, m); 130 } 131 132 if (i) 133 mb862xx_i2c_stop(adap); 134 135 return (err < 0) ? err : i; 136 } 137 138 static u32 mb862xx_func(struct i2c_adapter *adap) 139 { 140 return I2C_FUNC_SMBUS_BYTE_DATA; 141 } 142 143 static const struct i2c_algorithm mb862xx_algo = { 144 .master_xfer = mb862xx_xfer, 145 .functionality = mb862xx_func, 146 }; 147 148 static struct i2c_adapter mb862xx_i2c_adapter = { 149 .name = "MB862xx I2C adapter", 150 .algo = &mb862xx_algo, 151 .owner = THIS_MODULE, 152 }; 153 154 int mb862xx_i2c_init(struct mb862xxfb_par *par) 155 { 156 mb862xx_i2c_adapter.algo_data = par; 157 par->adap = &mb862xx_i2c_adapter; 158 159 return i2c_add_adapter(par->adap); 160 } 161 162 void mb862xx_i2c_exit(struct mb862xxfb_par *par) 163 { 164 if (par->adap) { 165 i2c_del_adapter(par->adap); 166 par->adap = NULL; 167 } 168 } 169