1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * SPI driver for Renesas Synchronization Management Unit (SMU) devices. |
4 | * |
5 | * Copyright (C) 2021 Integrated Device Technology, Inc., a Renesas Company. |
6 | */ |
7 | |
8 | #include <linux/init.h> |
9 | #include <linux/kernel.h> |
10 | #include <linux/mfd/core.h> |
11 | #include <linux/mfd/rsmu.h> |
12 | #include <linux/module.h> |
13 | #include <linux/of.h> |
14 | #include <linux/regmap.h> |
15 | #include <linux/slab.h> |
16 | #include <linux/spi/spi.h> |
17 | |
18 | #include "rsmu.h" |
19 | |
20 | #define RSMU_CM_PAGE_ADDR 0x7C |
21 | #define RSMU_SABRE_PAGE_ADDR 0x7F |
22 | #define RSMU_PAGE_MASK 0xFFFFFF80 |
23 | #define RSMU_ADDR_MASK 0x7F |
24 | |
25 | static int rsmu_read_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes) |
26 | { |
27 | struct spi_device *client = to_spi_device(dev: rsmu->dev); |
28 | struct spi_transfer xfer = {0}; |
29 | struct spi_message msg; |
30 | u8 cmd[RSMU_MAX_READ_COUNT + 1] = {0}; |
31 | u8 rsp[RSMU_MAX_READ_COUNT + 1] = {0}; |
32 | int ret; |
33 | |
34 | if (bytes > RSMU_MAX_READ_COUNT) |
35 | return -EINVAL; |
36 | |
37 | cmd[0] = reg | 0x80; |
38 | xfer.rx_buf = rsp; |
39 | xfer.len = bytes + 1; |
40 | xfer.tx_buf = cmd; |
41 | xfer.bits_per_word = client->bits_per_word; |
42 | xfer.speed_hz = client->max_speed_hz; |
43 | |
44 | spi_message_init(m: &msg); |
45 | spi_message_add_tail(t: &xfer, m: &msg); |
46 | |
47 | /* |
48 | * 4-wire SPI is a shift register, so for every byte you send, |
49 | * you get one back at the same time. Example read from 0xC024, |
50 | * which has value of 0x2D |
51 | * |
52 | * MOSI: |
53 | * 7C 00 C0 #Set page register |
54 | * A4 00 #MSB is set, so this is read command |
55 | * MISO: |
56 | * XX 2D #XX is a dummy byte from sending A4 and we |
57 | * need to throw it away |
58 | */ |
59 | ret = spi_sync(spi: client, message: &msg); |
60 | if (ret >= 0) |
61 | memcpy(buf, &rsp[1], xfer.len-1); |
62 | |
63 | return ret; |
64 | } |
65 | |
66 | static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes) |
67 | { |
68 | struct spi_device *client = to_spi_device(dev: rsmu->dev); |
69 | struct spi_transfer xfer = {0}; |
70 | struct spi_message msg; |
71 | u8 cmd[RSMU_MAX_WRITE_COUNT + 1] = {0}; |
72 | |
73 | if (bytes > RSMU_MAX_WRITE_COUNT) |
74 | return -EINVAL; |
75 | |
76 | cmd[0] = reg; |
77 | memcpy(&cmd[1], buf, bytes); |
78 | |
79 | xfer.len = bytes + 1; |
80 | xfer.tx_buf = cmd; |
81 | xfer.bits_per_word = client->bits_per_word; |
82 | xfer.speed_hz = client->max_speed_hz; |
83 | spi_message_init(m: &msg); |
84 | spi_message_add_tail(t: &xfer, m: &msg); |
85 | |
86 | return spi_sync(spi: client, message: &msg); |
87 | } |
88 | |
89 | /* |
90 | * 1-byte (1B) offset addressing: |
91 | * 16-bit register address: the lower 7 bits of the register address come |
92 | * from the offset addr byte and the upper 9 bits come from the page register. |
93 | */ |
94 | static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u32 reg) |
95 | { |
96 | u8 page_reg; |
97 | u8 buf[4]; |
98 | u16 bytes; |
99 | u32 page; |
100 | int err; |
101 | |
102 | switch (rsmu->type) { |
103 | case RSMU_CM: |
104 | /* Do not modify page register for none-scsr registers */ |
105 | if (reg < RSMU_CM_SCSR_BASE) |
106 | return 0; |
107 | page_reg = RSMU_CM_PAGE_ADDR; |
108 | page = reg & RSMU_PAGE_MASK; |
109 | buf[0] = (u8)(page & 0xff); |
110 | buf[1] = (u8)((page >> 8) & 0xff); |
111 | buf[2] = (u8)((page >> 16) & 0xff); |
112 | buf[3] = (u8)((page >> 24) & 0xff); |
113 | bytes = 4; |
114 | break; |
115 | case RSMU_SABRE: |
116 | /* Do not modify page register if reg is page register itself */ |
117 | if ((reg & RSMU_ADDR_MASK) == RSMU_ADDR_MASK) |
118 | return 0; |
119 | page_reg = RSMU_SABRE_PAGE_ADDR; |
120 | page = reg & RSMU_PAGE_MASK; |
121 | /* The three page bits are located in the single Page Register */ |
122 | buf[0] = (u8)((page >> 7) & 0x7); |
123 | bytes = 1; |
124 | break; |
125 | default: |
126 | dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n" , rsmu->type); |
127 | return -ENODEV; |
128 | } |
129 | |
130 | /* Simply return if we are on the same page */ |
131 | if (rsmu->page == page) |
132 | return 0; |
133 | |
134 | err = rsmu_write_device(rsmu, reg: page_reg, buf, bytes); |
135 | if (err) |
136 | dev_err(rsmu->dev, "Failed to set page offset 0x%x\n" , page); |
137 | else |
138 | /* Remember the last page */ |
139 | rsmu->page = page; |
140 | |
141 | return err; |
142 | } |
143 | |
144 | static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val) |
145 | { |
146 | struct rsmu_ddata *rsmu = spi_get_drvdata(spi: (struct spi_device *)context); |
147 | u8 addr = (u8)(reg & RSMU_ADDR_MASK); |
148 | int err; |
149 | |
150 | err = rsmu_write_page_register(rsmu, reg); |
151 | if (err) |
152 | return err; |
153 | |
154 | err = rsmu_read_device(rsmu, reg: addr, buf: (u8 *)val, bytes: 1); |
155 | if (err) |
156 | dev_err(rsmu->dev, "Failed to read offset address 0x%x\n" , addr); |
157 | |
158 | return err; |
159 | } |
160 | |
161 | static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val) |
162 | { |
163 | struct rsmu_ddata *rsmu = spi_get_drvdata(spi: (struct spi_device *)context); |
164 | u8 addr = (u8)(reg & RSMU_ADDR_MASK); |
165 | u8 data = (u8)val; |
166 | int err; |
167 | |
168 | err = rsmu_write_page_register(rsmu, reg); |
169 | if (err) |
170 | return err; |
171 | |
172 | err = rsmu_write_device(rsmu, reg: addr, buf: &data, bytes: 1); |
173 | if (err) |
174 | dev_err(rsmu->dev, |
175 | "Failed to write offset address 0x%x\n" , addr); |
176 | |
177 | return err; |
178 | } |
179 | |
180 | static const struct regmap_config rsmu_cm_regmap_config = { |
181 | .reg_bits = 32, |
182 | .val_bits = 8, |
183 | .max_register = 0x20120000, |
184 | .reg_read = rsmu_reg_read, |
185 | .reg_write = rsmu_reg_write, |
186 | .cache_type = REGCACHE_NONE, |
187 | }; |
188 | |
189 | static const struct regmap_config rsmu_sabre_regmap_config = { |
190 | .reg_bits = 16, |
191 | .val_bits = 8, |
192 | .max_register = 0x400, |
193 | .reg_read = rsmu_reg_read, |
194 | .reg_write = rsmu_reg_write, |
195 | .cache_type = REGCACHE_NONE, |
196 | }; |
197 | |
198 | static int rsmu_spi_probe(struct spi_device *client) |
199 | { |
200 | const struct spi_device_id *id = spi_get_device_id(sdev: client); |
201 | const struct regmap_config *cfg; |
202 | struct rsmu_ddata *rsmu; |
203 | int ret; |
204 | |
205 | rsmu = devm_kzalloc(dev: &client->dev, size: sizeof(*rsmu), GFP_KERNEL); |
206 | if (!rsmu) |
207 | return -ENOMEM; |
208 | |
209 | spi_set_drvdata(spi: client, data: rsmu); |
210 | |
211 | rsmu->dev = &client->dev; |
212 | rsmu->type = (enum rsmu_type)id->driver_data; |
213 | |
214 | /* Initialize regmap */ |
215 | switch (rsmu->type) { |
216 | case RSMU_CM: |
217 | cfg = &rsmu_cm_regmap_config; |
218 | break; |
219 | case RSMU_SABRE: |
220 | cfg = &rsmu_sabre_regmap_config; |
221 | break; |
222 | default: |
223 | dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n" , rsmu->type); |
224 | return -ENODEV; |
225 | } |
226 | |
227 | rsmu->regmap = devm_regmap_init(&client->dev, NULL, client, cfg); |
228 | if (IS_ERR(ptr: rsmu->regmap)) { |
229 | ret = PTR_ERR(ptr: rsmu->regmap); |
230 | dev_err(rsmu->dev, "Failed to allocate register map: %d\n" , ret); |
231 | return ret; |
232 | } |
233 | |
234 | return rsmu_core_init(rsmu); |
235 | } |
236 | |
237 | static void rsmu_spi_remove(struct spi_device *client) |
238 | { |
239 | struct rsmu_ddata *rsmu = spi_get_drvdata(spi: client); |
240 | |
241 | rsmu_core_exit(rsmu); |
242 | } |
243 | |
244 | static const struct spi_device_id rsmu_spi_id[] = { |
245 | { "8a34000" , RSMU_CM }, |
246 | { "8a34001" , RSMU_CM }, |
247 | { "82p33810" , RSMU_SABRE }, |
248 | { "82p33811" , RSMU_SABRE }, |
249 | {} |
250 | }; |
251 | MODULE_DEVICE_TABLE(spi, rsmu_spi_id); |
252 | |
253 | static const struct of_device_id rsmu_spi_of_match[] = { |
254 | { .compatible = "idt,8a34000" , .data = (void *)RSMU_CM }, |
255 | { .compatible = "idt,8a34001" , .data = (void *)RSMU_CM }, |
256 | { .compatible = "idt,82p33810" , .data = (void *)RSMU_SABRE }, |
257 | { .compatible = "idt,82p33811" , .data = (void *)RSMU_SABRE }, |
258 | {} |
259 | }; |
260 | MODULE_DEVICE_TABLE(of, rsmu_spi_of_match); |
261 | |
262 | static struct spi_driver rsmu_spi_driver = { |
263 | .driver = { |
264 | .name = "rsmu-spi" , |
265 | .of_match_table = rsmu_spi_of_match, |
266 | }, |
267 | .probe = rsmu_spi_probe, |
268 | .remove = rsmu_spi_remove, |
269 | .id_table = rsmu_spi_id, |
270 | }; |
271 | |
272 | static int __init rsmu_spi_init(void) |
273 | { |
274 | return spi_register_driver(&rsmu_spi_driver); |
275 | } |
276 | subsys_initcall(rsmu_spi_init); |
277 | |
278 | static void __exit rsmu_spi_exit(void) |
279 | { |
280 | spi_unregister_driver(sdrv: &rsmu_spi_driver); |
281 | } |
282 | module_exit(rsmu_spi_exit); |
283 | |
284 | MODULE_DESCRIPTION("Renesas SMU SPI driver" ); |
285 | MODULE_LICENSE("GPL" ); |
286 | |