1 /* 2 * Copyright (c) 2015 Google, Inc 3 * Written by Simon Glass <sjg@chromium.org> 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <common.h> 9 #include <dm.h> 10 #include <errno.h> 11 #include <i2c.h> 12 #include <dm/lists.h> 13 #include <dm/root.h> 14 15 /** 16 * struct i2c_mux: Information the uclass stores about an I2C mux 17 * 18 * @selected: Currently selected mux, or -1 for none 19 * @i2c_bus: I2C bus to use for communcation 20 */ 21 struct i2c_mux { 22 int selected; 23 struct udevice *i2c_bus; 24 }; 25 26 /** 27 * struct i2c_mux_bus: Information about each bus the mux controls 28 * 29 * @channel: Channel number used to select this bus 30 */ 31 struct i2c_mux_bus { 32 uint channel; 33 }; 34 35 /* Find out the mux channel number */ 36 static int i2c_mux_child_post_bind(struct udevice *dev) 37 { 38 struct i2c_mux_bus *plat = dev_get_parent_platdata(dev); 39 int channel; 40 41 if (device_get_uclass_id(dev) != UCLASS_I2C) 42 return 0; 43 44 channel = dev_read_u32_default(dev, "reg", -1); 45 if (channel < 0) 46 return -EINVAL; 47 plat->channel = channel; 48 49 return 0; 50 } 51 52 /* Find the I2C buses selected by this mux */ 53 static int i2c_mux_post_bind(struct udevice *mux) 54 { 55 ofnode node; 56 int ret; 57 58 debug("%s: %s\n", __func__, mux->name); 59 /* 60 * There is no compatible string in the sub-nodes, so we must manually 61 * bind these 62 */ 63 dev_for_each_subnode(node, mux) { 64 struct udevice *dev; 65 const char *name; 66 67 if (!ofnode_get_property(node, "reg", NULL)) 68 continue; 69 70 name = ofnode_get_name(node); 71 ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv", name, 72 node, &dev); 73 debug(" - bind ret=%d, %s\n", ret, dev ? dev->name : NULL); 74 if (ret) 75 return ret; 76 } 77 78 return 0; 79 } 80 81 /* Set up the mux ready for use */ 82 static int i2c_mux_post_probe(struct udevice *mux) 83 { 84 struct i2c_mux *priv = dev_get_uclass_priv(mux); 85 int ret; 86 87 debug("%s: %s\n", __func__, mux->name); 88 priv->selected = -1; 89 90 /* if parent is of i2c uclass already, we'll take that, otherwise 91 * look if we find an i2c-parent phandle 92 */ 93 if (UCLASS_I2C == device_get_uclass_id(mux->parent)) { 94 priv->i2c_bus = dev_get_parent(mux); 95 debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, 96 priv->i2c_bus->name); 97 return 0; 98 } 99 100 ret = uclass_get_device_by_phandle(UCLASS_I2C, mux, "i2c-parent", 101 &priv->i2c_bus); 102 if (ret) 103 return ret; 104 debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, priv->i2c_bus->name); 105 106 return 0; 107 } 108 109 int i2c_mux_select(struct udevice *dev) 110 { 111 struct i2c_mux_bus *plat = dev_get_parent_platdata(dev); 112 struct udevice *mux = dev->parent; 113 struct i2c_mux_ops *ops = i2c_mux_get_ops(mux); 114 115 if (!ops->select) 116 return -ENOSYS; 117 118 return ops->select(mux, dev, plat->channel); 119 } 120 121 int i2c_mux_deselect(struct udevice *dev) 122 { 123 struct i2c_mux_bus *plat = dev_get_parent_platdata(dev); 124 struct udevice *mux = dev->parent; 125 struct i2c_mux_ops *ops = i2c_mux_get_ops(mux); 126 127 if (!ops->deselect) 128 return -ENOSYS; 129 130 return ops->deselect(mux, dev, plat->channel); 131 } 132 133 static int i2c_mux_bus_set_bus_speed(struct udevice *dev, unsigned int speed) 134 { 135 struct udevice *mux = dev->parent; 136 struct i2c_mux *priv = dev_get_uclass_priv(mux); 137 int ret, ret2; 138 139 ret = i2c_mux_select(dev); 140 if (ret) 141 return ret; 142 ret = dm_i2c_set_bus_speed(priv->i2c_bus, speed); 143 ret2 = i2c_mux_deselect(dev); 144 145 return ret ? ret : ret2; 146 } 147 148 static int i2c_mux_bus_probe(struct udevice *dev, uint chip_addr, 149 uint chip_flags) 150 { 151 struct udevice *mux = dev->parent; 152 struct i2c_mux *priv = dev_get_uclass_priv(mux); 153 struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus); 154 int ret, ret2; 155 156 debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name); 157 if (!ops->probe_chip) 158 return -ENOSYS; 159 ret = i2c_mux_select(dev); 160 if (ret) 161 return ret; 162 ret = ops->probe_chip(priv->i2c_bus, chip_addr, chip_flags); 163 ret2 = i2c_mux_deselect(dev); 164 165 return ret ? ret : ret2; 166 } 167 168 static int i2c_mux_bus_xfer(struct udevice *dev, struct i2c_msg *msg, 169 int nmsgs) 170 { 171 struct udevice *mux = dev->parent; 172 struct i2c_mux *priv = dev_get_uclass_priv(mux); 173 struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus); 174 int ret, ret2; 175 176 debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name); 177 if (!ops->xfer) 178 return -ENOSYS; 179 ret = i2c_mux_select(dev); 180 if (ret) 181 return ret; 182 ret = ops->xfer(priv->i2c_bus, msg, nmsgs); 183 ret2 = i2c_mux_deselect(dev); 184 185 return ret ? ret : ret2; 186 } 187 188 static const struct dm_i2c_ops i2c_mux_bus_ops = { 189 .xfer = i2c_mux_bus_xfer, 190 .probe_chip = i2c_mux_bus_probe, 191 .set_bus_speed = i2c_mux_bus_set_bus_speed, 192 }; 193 194 U_BOOT_DRIVER(i2c_mux_bus) = { 195 .name = "i2c_mux_bus_drv", 196 .id = UCLASS_I2C, 197 .ops = &i2c_mux_bus_ops, 198 }; 199 200 UCLASS_DRIVER(i2c_mux) = { 201 .id = UCLASS_I2C_MUX, 202 .name = "i2c_mux", 203 .post_bind = i2c_mux_post_bind, 204 .post_probe = i2c_mux_post_probe, 205 .per_device_auto_alloc_size = sizeof(struct i2c_mux), 206 .per_child_platdata_auto_alloc_size = sizeof(struct i2c_mux_bus), 207 .child_post_bind = i2c_mux_child_post_bind, 208 }; 209