ofw_i2c_subr.c revision 1.1.6.9
1 /* $NetBSD: ofw_i2c_subr.c,v 1.1.6.9 2021/08/08 01:06:57 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 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: ofw_i2c_subr.c,v 1.1.6.9 2021/08/08 01:06:57 thorpej Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/device.h> 34 #include <sys/endian.h> 35 #include <sys/kmem.h> 36 #include <sys/systm.h> 37 #include <dev/ofw/openfirm.h> 38 #include <dev/i2c/i2cvar.h> 39 40 #ifdef __HAVE_OPENFIRMWARE_VARIANT_AAPL 41 /* 42 * Apple OpenFirmware implementations have the i2c device 43 * address shifted left 1 bit to account for the r/w bit 44 * on the wire. We also want to look at only the least- 45 * significant 8 bits of the address cell. 46 */ 47 #define OFW_I2C_ADDRESS_MASK __BITS(0,7) 48 #define OFW_I2C_ADDRESS_SHIFT 1 49 50 /* 51 * Some of Apple's older OpenFirmware implementations are rife with 52 * nodes lacking "compatible" properties. 53 */ 54 #define OFW_I2C_ALLOW_MISSING_COMPATIBLE_PROPERTY 55 #endif /* __HAVE_OPENFIRMWARE_VARIANT_AAPL */ 56 57 #ifdef __HAVE_OPENFIRMWARE_VARIANT_SUNW 58 /* 59 * Sun OpenFirmware implementations use 2 cells for the 60 * i2c device "reg" property, the first containing the 61 * channel number, the second containing the i2c device 62 * address shifted left 1 bit to account for the r/w bit 63 * on the wire. 64 */ 65 #define OFW_I2C_REG_NCELLS 2 66 #define OFW_I2C_REG_CHANNEL 0 67 #define OFW_I2C_REG_ADDRESS 1 68 #define OFW_I2C_ADDRESS_SHIFT 1 69 #endif /* __HAVE_OPENFIRMWARE_VARIANT_SUNW */ 70 71 #ifndef OFW_I2C_REG_NCELLS 72 #define OFW_I2C_REG_NCELLS 1 73 #endif 74 75 #ifndef OFW_I2C_REG_ADDRESS 76 #define OFW_I2C_REG_ADDRESS 0 77 #endif 78 79 /* No default for OFW_I2C_REG_CHANNEL. */ 80 81 #ifndef OFW_I2C_ADDRESS_MASK 82 #define OFW_I2C_ADDRESS_MASK __BITS(0,31) 83 #endif 84 85 #ifndef OFW_I2C_ADDRESS_SHIFT 86 #define OFW_I2C_ADDRESS_SHIFT 0 87 #endif 88 89 static bool 90 of_i2c_get_address(i2c_tag_t tag, int node, uint32_t *addrp) 91 { 92 uint32_t reg[OFW_I2C_REG_NCELLS]; 93 uint32_t addr; 94 #ifdef OFW_I2C_REG_CHANNEL 95 uint32_t channel; 96 #endif 97 98 if (OF_getprop(node, "reg", reg, sizeof(reg)) != sizeof(reg)) { 99 /* 100 * "reg" property is malformed; reject the device. 101 */ 102 return false; 103 } 104 105 addr = be32toh(reg[OFW_I2C_REG_ADDRESS]); 106 addr = (addr & OFW_I2C_ADDRESS_MASK) >> OFW_I2C_ADDRESS_SHIFT; 107 108 #ifdef OFW_I2C_REG_CHANNEL 109 /* 110 * If the channel in the "reg" property does not match, 111 * reject the device. 112 */ 113 channel = be32toh(reg[OFW_I2C_REG_CHANNEL]); 114 if (channel != tag->ic_channel) { 115 return false; 116 } 117 #endif 118 119 *addrp = addr; 120 return true; 121 } 122 123 /* 124 * This follows the Device Tree bindings for i2c, which for the most part 125 * work for the classical OpenFirmware implementations, as well. There are 126 * some quirks do deal with for different OpenFirmware implementations, which 127 * are mainly in how the "reg" property is interpreted. 128 */ 129 static int 130 of_i2c_enumerate_devices(device_t dev, devhandle_t call_handle, void *v) 131 { 132 struct i2c_enumerate_devices_args *args = v; 133 int i2c_node, node; 134 char name[32], compat_buf[32]; 135 prop_dictionary_t props; 136 uint32_t addr; 137 char *clist; 138 int clist_size; 139 bool cbrv; 140 141 i2c_node = devhandle_to_of(call_handle); 142 143 for (node = OF_child(i2c_node); node != 0; node = OF_peer(node)) { 144 if (OF_getprop(node, "name", name, sizeof(name)) <= 0) { 145 continue; 146 } 147 if (!of_i2c_get_address(args->ia->ia_tag, node, &addr)) { 148 continue; 149 } 150 151 clist_size = OF_getproplen(node, "compatible"); 152 if (clist_size <= 0) { 153 #ifndef OFW_I2C_ALLOW_MISSING_COMPATIBLE_PROPERTY 154 continue; 155 #else 156 clist_size = 0; 157 #endif 158 } 159 clist = kmem_tmpbuf_alloc(clist_size, 160 compat_buf, sizeof(compat_buf), KM_SLEEP); 161 if (OF_getprop(node, "compatible", clist, clist_size) < 162 clist_size) { 163 kmem_tmpbuf_free(clist, clist_size, compat_buf); 164 continue; 165 } 166 props = prop_dictionary_create(); 167 168 args->ia->ia_addr = (i2c_addr_t)addr; 169 args->ia->ia_name = name; 170 args->ia->ia_clist = clist; 171 args->ia->ia_clist_size = clist_size; 172 args->ia->ia_prop = props; 173 args->ia->ia_devhandle = devhandle_from_of(node); 174 175 cbrv = args->callback(dev, args); 176 177 prop_object_release(props); 178 kmem_tmpbuf_free(clist, clist_size, compat_buf); 179 180 if (!cbrv) { 181 break; 182 } 183 } 184 185 return 0; 186 } 187 OF_DEVICE_CALL_REGISTER("i2c-enumerate-devices", of_i2c_enumerate_devices); 188
Indexes created Tue Sep 30 11:09:46 GMT 2025