ofw_i2c_subr.c revision 1.1.6.7
1 /* $NetBSD: ofw_i2c_subr.c,v 1.1.6.7 2021/05/14 03:05:52 thorpej Exp $ */ 2 3 /* 4 * Copyright (c) 2021 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * Copyright 1998 31 * Digital Equipment Corporation. All rights reserved. 32 * 33 * This software is furnished under license and may be used and 34 * copied only in accordance with the following terms and conditions. 35 * Subject to these conditions, you may download, copy, install, 36 * use, modify and distribute this software in source and/or binary 37 * form. No title or ownership is transferred hereby. 38 * 39 * 1) Any source code used, modified or distributed must reproduce 40 * and retain this copyright notice and list of conditions as 41 * they appear in the source file. 42 * 43 * 2) No right is granted to use any trade name, trademark, or logo of 44 * Digital Equipment Corporation. Neither the "Digital Equipment 45 * Corporation" name nor any trademark or logo of Digital Equipment 46 * Corporation may be used to endorse or promote products derived 47 * from this software without the prior written permission of 48 * Digital Equipment Corporation. 49 * 50 * 3) This software is provided "AS-IS" and any express or implied 51 * warranties, including but not limited to, any implied warranties 52 * of merchantability, fitness for a particular purpose, or 53 * non-infringement are disclaimed. In no event shall DIGITAL be 54 * liable for any damages whatsoever, and in particular, DIGITAL 55 * shall not be liable for special, indirect, consequential, or 56 * incidental damages or damages for lost profits, loss of 57 * revenue or loss of use, whether such damages arise in contract, 58 * negligence, tort, under statute, in equity, at law or otherwise, 59 * even if advised of the possibility of such damage. 60 */ 61 62 #include <sys/cdefs.h> 63 __KERNEL_RCSID(0, "$NetBSD: ofw_i2c_subr.c,v 1.1.6.7 2021/05/14 03:05:52 thorpej Exp $"); 64 65 #include <sys/param.h> 66 #include <sys/device.h> 67 #include <sys/endian.h> 68 #include <sys/kmem.h> 69 #include <sys/systm.h> 70 #include <dev/ofw/openfirm.h> 71 #include <dev/i2c/i2cvar.h> 72 73 #ifdef __HAVE_OPENFIRMWARE_VARIANT_AAPL 74 /* 75 * Apple OpenFirmware implementations have the i2c device 76 * address shifted left 1 bit to account for the r/w bit 77 * on the wire. We also want to look at only the least- 78 * significant 8 bits of the address cell. 79 */ 80 #define OFW_I2C_ADDRESS_MASK __BITS(0,7) 81 #define OFW_I2C_ADDRESS_SHIFT 1 82 83 /* 84 * Some of Apple's older OpenFirmware implementations are rife with 85 * nodes lacking "compatible" properties. 86 */ 87 #define OFW_I2C_ALLOW_MISSING_COMPATIBLE_PROPERTY 88 #endif /* __HAVE_OPENFIRMWARE_VARIANT_AAPL */ 89 90 #ifdef __HAVE_OPENFIRMWARE_VARIANT_SUNW 91 /* 92 * Sun OpenFirmware implementations use 2 cells for the 93 * i2c device "reg" property, the first containing the 94 * channel number, the second containing the i2c device 95 * address shifted left 1 bit to account for the r/w bit 96 * on the wire. 97 */ 98 #define OFW_I2C_REG_NCELLS 2 99 #define OFW_I2C_REG_CHANNEL 0 100 #define OFW_I2C_REG_ADDRESS 1 101 #define OFW_I2C_ADDRESS_SHIFT 1 102 #endif /* __HAVE_OPENFIRMWARE_VARIANT_SUNW */ 103 104 #ifndef OFW_I2C_REG_NCELLS 105 #define OFW_I2C_REG_NCELLS 1 106 #endif 107 108 #ifndef OFW_I2C_REG_ADDRESS 109 #define OFW_I2C_REG_ADDRESS 0 110 #endif 111 112 /* No default for OFW_I2C_REG_CHANNEL. */ 113 114 #ifndef OFW_I2C_ADDRESS_MASK 115 #define OFW_I2C_ADDRESS_MASK __BITS(0,31) 116 #endif 117 118 #ifndef OFW_I2C_ADDRESS_SHIFT 119 #define OFW_I2C_ADDRESS_SHIFT 0 120 #endif 121 122 static bool 123 of_i2c_get_address(i2c_tag_t tag, int node, uint32_t *addrp) 124 { 125 uint32_t reg[OFW_I2C_REG_NCELLS]; 126 uint32_t addr; 127 #ifdef OFW_I2C_REG_CHANNEL 128 uint32_t channel; 129 #endif 130 131 if (OF_getprop(node, "reg", reg, sizeof(reg)) != sizeof(reg)) { 132 /* 133 * "reg" property is malformed; reject the device. 134 */ 135 return false; 136 } 137 138 addr = be32toh(reg[OFW_I2C_REG_ADDRESS]); 139 addr = (addr & OFW_I2C_ADDRESS_MASK) >> OFW_I2C_ADDRESS_SHIFT; 140 141 #ifdef OFW_I2C_REG_CHANNEL 142 /* 143 * If the channel in the "reg" property does not match, 144 * reject the device. 145 */ 146 channel = be32toh(reg[OFW_I2C_REG_CHANNEL]); 147 if (channel != tag->ic_channel) { 148 return false; 149 } 150 #endif 151 152 *addrp = addr; 153 return true; 154 } 155 156 /* 157 * This follows the Device Tree bindings for i2c, which for the most part 158 * work for the classical OpenFirmware implementations, as well. There are 159 * some quirks do deal with for different OpenFirmware implementations, which 160 * are mainly in how the "reg" property is interpreted. 161 */ 162 static int 163 of_i2c_enumerate_devices(device_t dev, devhandle_t call_handle, void *v) 164 { 165 struct i2c_enumerate_devices_args *args = v; 166 int i2c_node, node; 167 char name[32], compat_buf[32]; 168 prop_dictionary_t props; 169 uint32_t addr; 170 char *clist; 171 int clist_size; 172 bool cbrv; 173 174 i2c_node = devhandle_to_of(call_handle); 175 176 for (node = OF_child(i2c_node); node != 0; node = OF_peer(node)) { 177 if (OF_getprop(node, "name", name, sizeof(name)) <= 0) { 178 continue; 179 } 180 if (!of_i2c_get_address(args->ia->ia_tag, node, &addr)) { 181 continue; 182 } 183 184 clist_size = OF_getproplen(node, "compatible"); 185 #ifndef OFW_I2C_ALLOW_MISSING_COMPATIBLE_PROPERTY 186 if (clist_size <= 0) { 187 continue; 188 } 189 #endif 190 clist = kmem_tmpbuf_alloc(clist_size, 191 compat_buf, sizeof(compat_buf), KM_SLEEP); 192 if (OF_getprop(node, "compatible", clist, clist_size) < 193 clist_size) { 194 kmem_tmpbuf_free(clist, clist_size, compat_buf); 195 continue; 196 } 197 props = prop_dictionary_create(); 198 199 args->ia->ia_addr = (i2c_addr_t)addr; 200 args->ia->ia_name = name; 201 args->ia->ia_clist = clist; 202 args->ia->ia_clist_size = clist_size; 203 args->ia->ia_prop = props; 204 args->ia->ia_devhandle = devhandle_from_of(node); 205 206 cbrv = args->callback(dev, args); 207 208 prop_object_release(props); 209 kmem_tmpbuf_free(clist, clist_size, compat_buf); 210 211 if (!cbrv) { 212 break; 213 } 214 } 215 216 return 0; 217 } 218 OF_DEVICE_CALL_REGISTER("i2c-enumerate-devices", of_i2c_enumerate_devices); 219
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