1// SPDX-License-Identifier: GPL-2.0
2//
3// Register map access API - SPI support
4//
5// Copyright 2011 Wolfson Microelectronics plc
6//
7// Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8
9#include <linux/regmap.h>
10#include <linux/spi/spi.h>
11#include <linux/module.h>
12
13#include "internal.h"
14
15struct regmap_async_spi {
16	struct regmap_async core;
17	struct spi_message m;
18	struct spi_transfer t[2];
19};
20
21static void regmap_spi_complete(void *data)
22{
23	struct regmap_async_spi *async = data;
24
25	regmap_async_complete_cb(&async->core, async->m.status);
26}
27
28static int regmap_spi_write(void *context, const void *data, size_t count)
29{
30	struct device *dev = context;
31	struct spi_device *spi = to_spi_device(dev);
32
33	return spi_write(spi, data, count);
34}
35
36static int regmap_spi_gather_write(void *context,
37				   const void *reg, size_t reg_len,
38				   const void *val, size_t val_len)
39{
40	struct device *dev = context;
41	struct spi_device *spi = to_spi_device(dev);
42	struct spi_message m;
43	struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
44				     { .tx_buf = val, .len = val_len, }, };
45
46	spi_message_init(&m);
47	spi_message_add_tail(&t[0], &m);
48	spi_message_add_tail(&t[1], &m);
49
50	return spi_sync(spi, &m);
51}
52
53static int regmap_spi_async_write(void *context,
54				  const void *reg, size_t reg_len,
55				  const void *val, size_t val_len,
56				  struct regmap_async *a)
57{
58	struct regmap_async_spi *async = container_of(a,
59						      struct regmap_async_spi,
60						      core);
61	struct device *dev = context;
62	struct spi_device *spi = to_spi_device(dev);
63
64	async->t[0].tx_buf = reg;
65	async->t[0].len = reg_len;
66	async->t[1].tx_buf = val;
67	async->t[1].len = val_len;
68
69	spi_message_init(&async->m);
70	spi_message_add_tail(&async->t[0], &async->m);
71	if (val)
72		spi_message_add_tail(&async->t[1], &async->m);
73
74	async->m.complete = regmap_spi_complete;
75	async->m.context = async;
76
77	return spi_async(spi, &async->m);
78}
79
80static struct regmap_async *regmap_spi_async_alloc(void)
81{
82	struct regmap_async_spi *async_spi;
83
84	async_spi = kzalloc(sizeof(*async_spi), GFP_KERNEL);
85	if (!async_spi)
86		return NULL;
87
88	return &async_spi->core;
89}
90
91static int regmap_spi_read(void *context,
92			   const void *reg, size_t reg_size,
93			   void *val, size_t val_size)
94{
95	struct device *dev = context;
96	struct spi_device *spi = to_spi_device(dev);
97
98	return spi_write_then_read(spi, reg, reg_size, val, val_size);
99}
100
101static const struct regmap_bus regmap_spi = {
102	.write = regmap_spi_write,
103	.gather_write = regmap_spi_gather_write,
104	.async_write = regmap_spi_async_write,
105	.async_alloc = regmap_spi_async_alloc,
106	.read = regmap_spi_read,
107	.read_flag_mask = 0x80,
108	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
109	.val_format_endian_default = REGMAP_ENDIAN_BIG,
110};
111
112static const struct regmap_bus *regmap_get_spi_bus(struct spi_device *spi,
113						   const struct regmap_config *config)
114{
115	size_t max_size = spi_max_transfer_size(spi);
116	size_t max_msg_size, reg_reserve_size;
117	struct regmap_bus *bus;
118
119	if (max_size != SIZE_MAX) {
120		bus = kmemdup(&regmap_spi, sizeof(*bus), GFP_KERNEL);
121		if (!bus)
122			return ERR_PTR(-ENOMEM);
123
124		max_msg_size = spi_max_message_size(spi);
125		reg_reserve_size = config->reg_bits / BITS_PER_BYTE
126				 + config->pad_bits / BITS_PER_BYTE;
127		if (max_size + reg_reserve_size > max_msg_size)
128			max_size -= reg_reserve_size;
129
130		bus->free_on_exit = true;
131		bus->max_raw_read = max_size;
132		bus->max_raw_write = max_size;
133
134		return bus;
135	}
136
137	return &regmap_spi;
138}
139
140struct regmap *__regmap_init_spi(struct spi_device *spi,
141				 const struct regmap_config *config,
142				 struct lock_class_key *lock_key,
143				 const char *lock_name)
144{
145	const struct regmap_bus *bus = regmap_get_spi_bus(spi, config);
146
147	if (IS_ERR(bus))
148		return ERR_CAST(bus);
149
150	return __regmap_init(&spi->dev, bus, &spi->dev, config, lock_key, lock_name);
151}
152EXPORT_SYMBOL_GPL(__regmap_init_spi);
153
154struct regmap *__devm_regmap_init_spi(struct spi_device *spi,
155				      const struct regmap_config *config,
156				      struct lock_class_key *lock_key,
157				      const char *lock_name)
158{
159	const struct regmap_bus *bus = regmap_get_spi_bus(spi, config);
160
161	if (IS_ERR(bus))
162		return ERR_CAST(bus);
163
164	return __devm_regmap_init(&spi->dev, bus, &spi->dev, config, lock_key, lock_name);
165}
166EXPORT_SYMBOL_GPL(__devm_regmap_init_spi);
167
168MODULE_LICENSE("GPL");
169