1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/drivers/mfd/mcp-core.c
4  *
5  *  Copyright (C) 2001 Russell King
6  *
7  *  Generic MCP (Multimedia Communications Port) layer.  All MCP locking
8  *  is solely held within this file.
9  */
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/errno.h>
13 #include <linux/smp.h>
14 #include <linux/device.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/mfd/mcp.h>
18 
19 
20 #define to_mcp(d)		container_of(d, struct mcp, attached_device)
21 #define to_mcp_driver(d)	container_of(d, struct mcp_driver, drv)
22 
mcp_bus_match(struct device * dev,struct device_driver * drv)23 static int mcp_bus_match(struct device *dev, struct device_driver *drv)
24 {
25 	return 1;
26 }
27 
mcp_bus_probe(struct device * dev)28 static int mcp_bus_probe(struct device *dev)
29 {
30 	struct mcp *mcp = to_mcp(dev);
31 	struct mcp_driver *drv = to_mcp_driver(dev->driver);
32 
33 	return drv->probe(mcp);
34 }
35 
mcp_bus_remove(struct device * dev)36 static void mcp_bus_remove(struct device *dev)
37 {
38 	struct mcp *mcp = to_mcp(dev);
39 	struct mcp_driver *drv = to_mcp_driver(dev->driver);
40 
41 	drv->remove(mcp);
42 }
43 
44 static struct bus_type mcp_bus_type = {
45 	.name		= "mcp",
46 	.match		= mcp_bus_match,
47 	.probe		= mcp_bus_probe,
48 	.remove		= mcp_bus_remove,
49 };
50 
51 /**
52  *	mcp_set_telecom_divisor - set the telecom divisor
53  *	@mcp: MCP interface structure
54  *	@div: SIB clock divisor
55  *
56  *	Set the telecom divisor on the MCP interface.  The resulting
57  *	sample rate is SIBCLOCK/div.
58  */
mcp_set_telecom_divisor(struct mcp * mcp,unsigned int div)59 void mcp_set_telecom_divisor(struct mcp *mcp, unsigned int div)
60 {
61 	unsigned long flags;
62 
63 	spin_lock_irqsave(&mcp->lock, flags);
64 	mcp->ops->set_telecom_divisor(mcp, div);
65 	spin_unlock_irqrestore(&mcp->lock, flags);
66 }
67 EXPORT_SYMBOL(mcp_set_telecom_divisor);
68 
69 /**
70  *	mcp_set_audio_divisor - set the audio divisor
71  *	@mcp: MCP interface structure
72  *	@div: SIB clock divisor
73  *
74  *	Set the audio divisor on the MCP interface.
75  */
mcp_set_audio_divisor(struct mcp * mcp,unsigned int div)76 void mcp_set_audio_divisor(struct mcp *mcp, unsigned int div)
77 {
78 	unsigned long flags;
79 
80 	spin_lock_irqsave(&mcp->lock, flags);
81 	mcp->ops->set_audio_divisor(mcp, div);
82 	spin_unlock_irqrestore(&mcp->lock, flags);
83 }
84 EXPORT_SYMBOL(mcp_set_audio_divisor);
85 
86 /**
87  *	mcp_reg_write - write a device register
88  *	@mcp: MCP interface structure
89  *	@reg: 4-bit register index
90  *	@val: 16-bit data value
91  *
92  *	Write a device register.  The MCP interface must be enabled
93  *	to prevent this function hanging.
94  */
mcp_reg_write(struct mcp * mcp,unsigned int reg,unsigned int val)95 void mcp_reg_write(struct mcp *mcp, unsigned int reg, unsigned int val)
96 {
97 	unsigned long flags;
98 
99 	spin_lock_irqsave(&mcp->lock, flags);
100 	mcp->ops->reg_write(mcp, reg, val);
101 	spin_unlock_irqrestore(&mcp->lock, flags);
102 }
103 EXPORT_SYMBOL(mcp_reg_write);
104 
105 /**
106  *	mcp_reg_read - read a device register
107  *	@mcp: MCP interface structure
108  *	@reg: 4-bit register index
109  *
110  *	Read a device register and return its value.  The MCP interface
111  *	must be enabled to prevent this function hanging.
112  */
mcp_reg_read(struct mcp * mcp,unsigned int reg)113 unsigned int mcp_reg_read(struct mcp *mcp, unsigned int reg)
114 {
115 	unsigned long flags;
116 	unsigned int val;
117 
118 	spin_lock_irqsave(&mcp->lock, flags);
119 	val = mcp->ops->reg_read(mcp, reg);
120 	spin_unlock_irqrestore(&mcp->lock, flags);
121 
122 	return val;
123 }
124 EXPORT_SYMBOL(mcp_reg_read);
125 
126 /**
127  *	mcp_enable - enable the MCP interface
128  *	@mcp: MCP interface to enable
129  *
130  *	Enable the MCP interface.  Each call to mcp_enable will need
131  *	a corresponding call to mcp_disable to disable the interface.
132  */
mcp_enable(struct mcp * mcp)133 void mcp_enable(struct mcp *mcp)
134 {
135 	unsigned long flags;
136 
137 	spin_lock_irqsave(&mcp->lock, flags);
138 	if (mcp->use_count++ == 0)
139 		mcp->ops->enable(mcp);
140 	spin_unlock_irqrestore(&mcp->lock, flags);
141 }
142 EXPORT_SYMBOL(mcp_enable);
143 
144 /**
145  *	mcp_disable - disable the MCP interface
146  *	@mcp: MCP interface to disable
147  *
148  *	Disable the MCP interface.  The MCP interface will only be
149  *	disabled once the number of calls to mcp_enable matches the
150  *	number of calls to mcp_disable.
151  */
mcp_disable(struct mcp * mcp)152 void mcp_disable(struct mcp *mcp)
153 {
154 	unsigned long flags;
155 
156 	spin_lock_irqsave(&mcp->lock, flags);
157 	if (--mcp->use_count == 0)
158 		mcp->ops->disable(mcp);
159 	spin_unlock_irqrestore(&mcp->lock, flags);
160 }
161 EXPORT_SYMBOL(mcp_disable);
162 
mcp_release(struct device * dev)163 static void mcp_release(struct device *dev)
164 {
165 	struct mcp *mcp = container_of(dev, struct mcp, attached_device);
166 
167 	kfree(mcp);
168 }
169 
mcp_host_alloc(struct device * parent,size_t size)170 struct mcp *mcp_host_alloc(struct device *parent, size_t size)
171 {
172 	struct mcp *mcp;
173 
174 	mcp = kzalloc(sizeof(struct mcp) + size, GFP_KERNEL);
175 	if (mcp) {
176 		spin_lock_init(&mcp->lock);
177 		device_initialize(&mcp->attached_device);
178 		mcp->attached_device.parent = parent;
179 		mcp->attached_device.bus = &mcp_bus_type;
180 		mcp->attached_device.dma_mask = parent->dma_mask;
181 		mcp->attached_device.release = mcp_release;
182 	}
183 	return mcp;
184 }
185 EXPORT_SYMBOL(mcp_host_alloc);
186 
mcp_host_add(struct mcp * mcp,void * pdata)187 int mcp_host_add(struct mcp *mcp, void *pdata)
188 {
189 	mcp->attached_device.platform_data = pdata;
190 	dev_set_name(&mcp->attached_device, "mcp0");
191 	return device_add(&mcp->attached_device);
192 }
193 EXPORT_SYMBOL(mcp_host_add);
194 
mcp_host_del(struct mcp * mcp)195 void mcp_host_del(struct mcp *mcp)
196 {
197 	device_del(&mcp->attached_device);
198 }
199 EXPORT_SYMBOL(mcp_host_del);
200 
mcp_host_free(struct mcp * mcp)201 void mcp_host_free(struct mcp *mcp)
202 {
203 	put_device(&mcp->attached_device);
204 }
205 EXPORT_SYMBOL(mcp_host_free);
206 
mcp_driver_register(struct mcp_driver * mcpdrv)207 int mcp_driver_register(struct mcp_driver *mcpdrv)
208 {
209 	mcpdrv->drv.bus = &mcp_bus_type;
210 	return driver_register(&mcpdrv->drv);
211 }
212 EXPORT_SYMBOL(mcp_driver_register);
213 
mcp_driver_unregister(struct mcp_driver * mcpdrv)214 void mcp_driver_unregister(struct mcp_driver *mcpdrv)
215 {
216 	driver_unregister(&mcpdrv->drv);
217 }
218 EXPORT_SYMBOL(mcp_driver_unregister);
219 
mcp_init(void)220 static int __init mcp_init(void)
221 {
222 	return bus_register(&mcp_bus_type);
223 }
224 
mcp_exit(void)225 static void __exit mcp_exit(void)
226 {
227 	bus_unregister(&mcp_bus_type);
228 }
229 
230 module_init(mcp_init);
231 module_exit(mcp_exit);
232 
233 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
234 MODULE_DESCRIPTION("Core multimedia communications port driver");
235 MODULE_LICENSE("GPL");
236