ofw_i2c_subr.c revision 1.1.6.6
1 /* $NetBSD: ofw_i2c_subr.c,v 1.1.6.6 2021/05/14 02:51:43 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 1.1.6.6 2021/05/14 02:51:43 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 #endif /* __HAVE_OPENFIRMWARE_VARIANT_AAPL */ 83 84 #ifdef __HAVE_OPENFIRMWARE_VARIANT_SUNW 85 /* 86 * Sun OpenFirmware implementations use 2 cells for the 87 * i2c device "reg" property, the first containing the 88 * channel number, the second containing the i2c device 89 * address shifted left 1 bit to account for the r/w bit 90 * on the wire. 91 */ 92 #define OFW_I2C_REG_NCELLS 2 93 #define OFW_I2C_REG_CHANNEL 0 94 #define OFW_I2C_REG_ADDRESS 1 95 #define OFW_I2C_ADDRESS_SHIFT 1 96 #endif /* __HAVE_OPENFIRMWARE_VARIANT_SUNW */ 97 98 #ifndef OFW_I2C_REG_NCELLS 99 #define OFW_I2C_REG_NCELLS 1 100 #endif 101 102 #ifndef OFW_I2C_REG_ADDRESS 103 #define OFW_I2C_REG_ADDRESS 0 104 #endif 105 106 /* No default for OFW_I2C_REG_CHANNEL. */ 107 108 #ifndef OFW_I2C_ADDRESS_MASK 109 #define OFW_I2C_ADDRESS_MASK __BITS(0,31) 110 #endif 111 112 #ifndef OFW_I2C_ADDRESS_SHIFT 113 #define OFW_I2C_ADDRESS_SHIFT 0 114 #endif 115 116 static bool 117 of_i2c_get_address(i2c_tag_t tag, int node, uint32_t *addrp) 118 { 119 uint32_t reg[OFW_I2C_REG_NCELLS]; 120 uint32_t addr; 121 #ifdef OFW_I2C_REG_CHANNEL 122 uint32_t channel; 123 #endif 124 125 if (OF_getprop(node, "reg", reg, sizeof(reg)) != sizeof(reg)) { 126 /* 127 * "reg" property is malformed; reject the device. 128 */ 129 return false; 130 } 131 132 addr = be32toh(reg[OFW_I2C_REG_ADDRESS]); 133 addr = (addr & OFW_I2C_ADDRESS_MASK) >> OFW_I2C_ADDRESS_SHIFT; 134 135 #ifdef OFW_I2C_REG_CHANNEL 136 /* 137 * If the channel in the "reg" property does not match, 138 * reject the device. 139 */ 140 channel = be32toh(reg[OFW_I2C_REG_CHANNEL]); 141 if (channel != tag->ic_channel) { 142 return false; 143 } 144 #endif 145 146 *addrp = addr; 147 return true; 148 } 149 150 /* 151 * This follows the Device Tree bindings for i2c, which for the most part 152 * work for the classical OpenFirmware implementations, as well. There are 153 * some quirks do deal with for different OpenFirmware implementations, which 154 * are mainly in how the "reg" property is interpreted. 155 */ 156 static int 157 of_i2c_enumerate_devices(device_t dev, devhandle_t call_handle, void *v) 158 { 159 struct i2c_enumerate_devices_args *args = v; 160 int i2c_node, node; 161 char name[32], compat_buf[32]; 162 prop_dictionary_t props; 163 uint32_t addr; 164 char *clist; 165 int clist_size; 166 bool cbrv; 167 168 i2c_node = devhandle_to_of(call_handle); 169 170 for (node = OF_child(i2c_node); node != 0; node = OF_peer(node)) { 171 if (OF_getprop(node, "name", name, sizeof(name)) <= 0) { 172 continue; 173 } 174 if (!of_i2c_get_address(args->ia->ia_tag, node, &addr)) { 175 continue; 176 } 177 178 clist_size = OF_getproplen(node, "compatible"); 179 clist = kmem_tmpbuf_alloc(clist_size, 180 compat_buf, sizeof(compat_buf), KM_SLEEP); 181 if (OF_getprop(node, "compatible", clist, clist_size) < 182 clist_size) { 183 kmem_tmpbuf_free(clist, clist_size, compat_buf); 184 continue; 185 } 186 props = prop_dictionary_create(); 187 188 args->ia->ia_addr = (i2c_addr_t)addr; 189 args->ia->ia_name = name; 190 args->ia->ia_clist = clist; 191 args->ia->ia_clist_size = clist_size; 192 args->ia->ia_prop = props; 193 args->ia->ia_devhandle = devhandle_from_of(node); 194 195 cbrv = args->callback(dev, args); 196 197 prop_object_release(props); 198 kmem_tmpbuf_free(clist, clist_size, compat_buf); 199 200 if (!cbrv) { 201 break; 202 } 203 } 204 205 return 0; 206 } 207 OF_DEVICE_CALL_REGISTER("i2c-enumerate-devices", of_i2c_enumerate_devices); 208
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