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 DECLARE_GLOBAL_DATA_PTR;
16 
17 /**
18  * struct i2c_mux: Information the uclass stores about an I2C mux
19  *
20  * @selected:	Currently selected mux, or -1 for none
21  * @i2c_bus: I2C bus to use for communcation
22  */
23 struct i2c_mux {
24 	int selected;
25 	struct udevice *i2c_bus;
26 };
27 
28 /**
29  * struct i2c_mux_bus: Information about each bus the mux controls
30  *
31  * @channel: Channel number used to select this bus
32  */
33 struct i2c_mux_bus {
34 	uint channel;
35 };
36 
37 /* Find out the mux channel number */
38 static int i2c_mux_child_post_bind(struct udevice *dev)
39 {
40 	struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
41 	int channel;
42 
43 	channel = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", -1);
44 	if (channel < 0)
45 		return -EINVAL;
46 	plat->channel = channel;
47 
48 	return 0;
49 }
50 
51 /* Find the I2C buses selected by this mux */
52 static int i2c_mux_post_bind(struct udevice *mux)
53 {
54 	const void *blob = gd->fdt_blob;
55 	int ret;
56 	int offset;
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 	for (offset = fdt_first_subnode(blob, mux->of_offset);
64 	     offset > 0;
65 	     offset = fdt_next_subnode(blob, offset)) {
66 		struct udevice *dev;
67 		const char *name;
68 
69 		name = fdt_get_name(blob, offset, NULL);
70 		ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv", name,
71 						 offset, &dev);
72 		debug("   - bind ret=%d, %s\n", ret, dev ? dev->name : NULL);
73 		if (ret)
74 			return ret;
75 	}
76 
77 	return 0;
78 }
79 
80 /* Set up the mux ready for use */
81 static int i2c_mux_post_probe(struct udevice *mux)
82 {
83 	struct i2c_mux *priv = dev_get_uclass_priv(mux);
84 	int ret;
85 
86 	debug("%s: %s\n", __func__, mux->name);
87 	priv->selected = -1;
88 
89 	ret = uclass_get_device_by_phandle(UCLASS_I2C, mux, "i2c-parent",
90 					   &priv->i2c_bus);
91 	if (ret)
92 		return ret;
93 	debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, priv->i2c_bus->name);
94 
95 	return 0;
96 }
97 
98 int i2c_mux_select(struct udevice *dev)
99 {
100 	struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
101 	struct udevice *mux = dev->parent;
102 	struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
103 
104 	if (!ops->select)
105 		return -ENOSYS;
106 
107 	return ops->select(mux, dev, plat->channel);
108 }
109 
110 int i2c_mux_deselect(struct udevice *dev)
111 {
112 	struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
113 	struct udevice *mux = dev->parent;
114 	struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
115 
116 	if (!ops->deselect)
117 		return -ENOSYS;
118 
119 	return ops->deselect(mux, dev, plat->channel);
120 }
121 
122 static int i2c_mux_bus_set_bus_speed(struct udevice *dev, unsigned int speed)
123 {
124 	struct udevice *mux = dev->parent;
125 	struct i2c_mux *priv = dev_get_uclass_priv(mux);
126 	int ret, ret2;
127 
128 	ret = i2c_mux_select(dev);
129 	if (ret)
130 		return ret;
131 	ret = dm_i2c_set_bus_speed(priv->i2c_bus, speed);
132 	ret2 = i2c_mux_deselect(dev);
133 
134 	return ret ? ret : ret2;
135 }
136 
137 static int i2c_mux_bus_probe(struct udevice *dev, uint chip_addr,
138 			     uint chip_flags)
139 {
140 	struct udevice *mux = dev->parent;
141 	struct i2c_mux *priv = dev_get_uclass_priv(mux);
142 	struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
143 	int ret, ret2;
144 
145 	debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
146 	if (!ops->probe_chip)
147 		return -ENOSYS;
148 	ret = i2c_mux_select(dev);
149 	if (ret)
150 		return ret;
151 	ret = ops->probe_chip(priv->i2c_bus, chip_addr, chip_flags);
152 	ret2 = i2c_mux_deselect(dev);
153 
154 	return ret ? ret : ret2;
155 }
156 
157 static int i2c_mux_bus_xfer(struct udevice *dev, struct i2c_msg *msg,
158 			    int nmsgs)
159 {
160 	struct udevice *mux = dev->parent;
161 	struct i2c_mux *priv = dev_get_uclass_priv(mux);
162 	struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
163 	int ret, ret2;
164 
165 	debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
166 	if (!ops->xfer)
167 		return -ENOSYS;
168 	ret = i2c_mux_select(dev);
169 	if (ret)
170 		return ret;
171 	ret = ops->xfer(priv->i2c_bus, msg, nmsgs);
172 	ret2 = i2c_mux_deselect(dev);
173 
174 	return ret ? ret : ret2;
175 }
176 
177 static const struct dm_i2c_ops i2c_mux_bus_ops = {
178 	.xfer		= i2c_mux_bus_xfer,
179 	.probe_chip	= i2c_mux_bus_probe,
180 	.set_bus_speed	= i2c_mux_bus_set_bus_speed,
181 };
182 
183 U_BOOT_DRIVER(i2c_mux_bus) = {
184 	.name		= "i2c_mux_bus_drv",
185 	.id		= UCLASS_I2C,
186 	.per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
187 	.ops	= &i2c_mux_bus_ops,
188 };
189 
190 UCLASS_DRIVER(i2c_mux) = {
191 	.id		= UCLASS_I2C_MUX,
192 	.name		= "i2c_mux",
193 	.post_bind	= i2c_mux_post_bind,
194 	.post_probe	= i2c_mux_post_probe,
195 	.per_device_auto_alloc_size = sizeof(struct i2c_mux),
196 	.per_child_platdata_auto_alloc_size = sizeof(struct i2c_mux_bus),
197 	.child_post_bind = i2c_mux_child_post_bind,
198 };
199