1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * 4 * Copyright (c) 2015 Free Electrons 5 * Copyright (c) 2015 NextThing Co. 6 * Copyright (c) 2018 Microchip Technology, Inc. 7 * 8 * Maxime Ripard <maxime.ripard@free-electrons.com> 9 * Eugen Hristev <eugen.hristev@microchip.com> 10 * 11 */ 12 13 #include <common.h> 14 #include <dm.h> 15 #include <w1.h> 16 #include <w1-eeprom.h> 17 18 #include <dm/device-internal.h> 19 20 #define W1_MATCH_ROM 0x55 21 #define W1_SKIP_ROM 0xcc 22 #define W1_SEARCH 0xf0 23 24 struct w1_bus { 25 u64 search_id; 26 }; 27 28 static int w1_enumerate(struct udevice *bus) 29 { 30 const struct w1_ops *ops = device_get_ops(bus); 31 struct w1_bus *w1 = dev_get_uclass_priv(bus); 32 u64 last_rn, rn = w1->search_id, tmp64; 33 bool last_device = false; 34 int search_bit, desc_bit = 64; 35 int last_zero = -1; 36 u8 triplet_ret = 0; 37 int i; 38 39 if (!ops->reset || !ops->write_byte || !ops->triplet) 40 return -ENOSYS; 41 42 while (!last_device) { 43 last_rn = rn; 44 rn = 0; 45 46 /* 47 * Reset bus and all 1-wire device state machines 48 * so they can respond to our requests. 49 * 50 * Return 0 - device(s) present, 1 - no devices present. 51 */ 52 if (ops->reset(bus)) { 53 debug("%s: No devices present on the wire.\n", 54 __func__); 55 break; 56 } 57 58 /* Start the search */ 59 ops->write_byte(bus, W1_SEARCH); 60 for (i = 0; i < 64; ++i) { 61 /* Determine the direction/search bit */ 62 if (i == desc_bit) 63 /* took the 0 path last time, so take the 1 path */ 64 search_bit = 1; 65 else if (i > desc_bit) 66 /* take the 0 path on the next branch */ 67 search_bit = 0; 68 else 69 search_bit = ((last_rn >> i) & 0x1); 70 71 /* Read two bits and write one bit */ 72 triplet_ret = ops->triplet(bus, search_bit); 73 74 /* quit if no device responded */ 75 if ((triplet_ret & 0x03) == 0x03) 76 break; 77 78 /* If both directions were valid, and we took the 0 path... */ 79 if (triplet_ret == 0) 80 last_zero = i; 81 82 /* extract the direction taken & update the device number */ 83 tmp64 = (triplet_ret >> 2); 84 rn |= (tmp64 << i); 85 } 86 87 if ((triplet_ret & 0x03) != 0x03) { 88 if (desc_bit == last_zero || last_zero < 0) { 89 last_device = 1; 90 w1->search_id = 0; 91 } else { 92 w1->search_id = rn; 93 } 94 desc_bit = last_zero; 95 96 debug("%s: Detected new device 0x%llx (family 0x%x)\n", 97 bus->name, rn, (u8)(rn & 0xff)); 98 99 /* attempt to register as w1-eeprom device */ 100 w1_eeprom_register_new_device(rn); 101 } 102 } 103 104 return 0; 105 } 106 107 int w1_get_bus(int busnum, struct udevice **busp) 108 { 109 int ret, i = 0; 110 111 struct udevice *dev; 112 113 for (ret = uclass_first_device(UCLASS_W1, &dev); 114 dev && !ret; 115 ret = uclass_next_device(&dev), i++) { 116 if (i == busnum) { 117 *busp = dev; 118 return 0; 119 } 120 } 121 122 if (!ret) { 123 debug("Cannot find w1 bus %d\n", busnum); 124 ret = -ENODEV; 125 } 126 127 return ret; 128 } 129 130 u8 w1_get_device_family(struct udevice *dev) 131 { 132 struct w1_device *w1 = dev_get_parent_platdata(dev); 133 134 return w1->id & 0xff; 135 } 136 137 int w1_reset_select(struct udevice *dev) 138 { 139 struct w1_device *w1 = dev_get_parent_platdata(dev); 140 struct udevice *bus = dev_get_parent(dev); 141 const struct w1_ops *ops = device_get_ops(bus); 142 int i; 143 144 if (!ops->reset || !ops->write_byte) 145 return -ENOSYS; 146 147 ops->reset(bus); 148 149 ops->write_byte(bus, W1_MATCH_ROM); 150 151 for (i = 0; i < sizeof(w1->id); i++) 152 ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff); 153 154 return 0; 155 } 156 157 int w1_read_byte(struct udevice *dev) 158 { 159 struct udevice *bus = dev_get_parent(dev); 160 const struct w1_ops *ops = device_get_ops(bus); 161 162 if (!ops->read_byte) 163 return -ENOSYS; 164 165 return ops->read_byte(bus); 166 } 167 168 int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count) 169 { 170 int i, ret; 171 172 for (i = 0; i < count; i++) { 173 ret = w1_read_byte(dev); 174 if (ret < 0) 175 return ret; 176 177 buf[i] = ret & 0xff; 178 } 179 180 return 0; 181 } 182 183 int w1_write_byte(struct udevice *dev, u8 byte) 184 { 185 struct udevice *bus = dev_get_parent(dev); 186 const struct w1_ops *ops = device_get_ops(bus); 187 188 if (!ops->write_byte) 189 return -ENOSYS; 190 191 ops->write_byte(bus, byte); 192 193 return 0; 194 } 195 196 static int w1_post_probe(struct udevice *bus) 197 { 198 w1_enumerate(bus); 199 200 return 0; 201 } 202 203 int w1_init(void) 204 { 205 struct udevice *bus; 206 struct uclass *uc; 207 int ret; 208 209 ret = uclass_get(UCLASS_W1, &uc); 210 if (ret) 211 return ret; 212 213 uclass_foreach_dev(bus, uc) { 214 ret = device_probe(bus); 215 if (ret == -ENODEV) { /* No such device. */ 216 printf("W1 controller not available.\n"); 217 continue; 218 } 219 220 if (ret) { /* Other error. */ 221 printf("W1 controller probe failed.\n"); 222 continue; 223 } 224 } 225 return 0; 226 } 227 228 UCLASS_DRIVER(w1) = { 229 .name = "w1", 230 .id = UCLASS_W1, 231 .flags = DM_UC_FLAG_SEQ_ALIAS, 232 .per_device_auto_alloc_size = sizeof(struct w1_bus), 233 .post_probe = w1_post_probe, 234 #if CONFIG_IS_ENABLED(OF_CONTROL) 235 .post_bind = dm_scan_fdt_dev, 236 #endif 237 .per_child_platdata_auto_alloc_size = sizeof(struct w1_device), 238 }; 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