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3ce8859e GR |
1 | /* |
2 | * NXP SC18IS602/603 SPI driver | |
3 | * | |
4 | * Copyright (C) Guenter Roeck <linux@roeck-us.net> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
3ce8859e GR |
15 | */ |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/spi/spi.h> | |
21 | #include <linux/i2c.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/pm_runtime.h> | |
24 | #include <linux/of.h> | |
25 | #include <linux/platform_data/sc18is602.h> | |
f9900801 | 26 | #include <linux/gpio/consumer.h> |
3ce8859e GR |
27 | |
28 | enum chips { sc18is602, sc18is602b, sc18is603 }; | |
29 | ||
30 | #define SC18IS602_BUFSIZ 200 | |
31 | #define SC18IS602_CLOCK 7372000 | |
32 | ||
33 | #define SC18IS602_MODE_CPHA BIT(2) | |
34 | #define SC18IS602_MODE_CPOL BIT(3) | |
35 | #define SC18IS602_MODE_LSB_FIRST BIT(5) | |
36 | #define SC18IS602_MODE_CLOCK_DIV_4 0x0 | |
37 | #define SC18IS602_MODE_CLOCK_DIV_16 0x1 | |
38 | #define SC18IS602_MODE_CLOCK_DIV_64 0x2 | |
39 | #define SC18IS602_MODE_CLOCK_DIV_128 0x3 | |
40 | ||
41 | struct sc18is602 { | |
42 | struct spi_master *master; | |
43 | struct device *dev; | |
44 | u8 ctrl; | |
45 | u32 freq; | |
46 | u32 speed; | |
47 | ||
48 | /* I2C data */ | |
49 | struct i2c_client *client; | |
50 | enum chips id; | |
51 | u8 buffer[SC18IS602_BUFSIZ + 1]; | |
52 | int tlen; /* Data queued for tx in buffer */ | |
53 | int rindex; /* Receive data index in buffer */ | |
f9900801 PR |
54 | |
55 | struct gpio_desc *reset; | |
3ce8859e GR |
56 | }; |
57 | ||
58 | static int sc18is602_wait_ready(struct sc18is602 *hw, int len) | |
59 | { | |
60 | int i, err; | |
61 | int usecs = 1000000 * len / hw->speed + 1; | |
62 | u8 dummy[1]; | |
63 | ||
64 | for (i = 0; i < 10; i++) { | |
65 | err = i2c_master_recv(hw->client, dummy, 1); | |
66 | if (err >= 0) | |
67 | return 0; | |
68 | usleep_range(usecs, usecs * 2); | |
69 | } | |
70 | return -ETIMEDOUT; | |
71 | } | |
72 | ||
73 | static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg, | |
74 | struct spi_transfer *t, bool do_transfer) | |
75 | { | |
76 | unsigned int len = t->len; | |
77 | int ret; | |
78 | ||
79 | if (hw->tlen == 0) { | |
80 | /* First byte (I2C command) is chip select */ | |
81 | hw->buffer[0] = 1 << msg->spi->chip_select; | |
82 | hw->tlen = 1; | |
83 | hw->rindex = 0; | |
84 | } | |
85 | /* | |
86 | * We can not immediately send data to the chip, since each I2C message | |
87 | * resembles a full SPI message (from CS active to CS inactive). | |
88 | * Enqueue messages up to the first read or until do_transfer is true. | |
89 | */ | |
90 | if (t->tx_buf) { | |
91 | memcpy(&hw->buffer[hw->tlen], t->tx_buf, len); | |
92 | hw->tlen += len; | |
93 | if (t->rx_buf) | |
94 | do_transfer = true; | |
95 | else | |
96 | hw->rindex = hw->tlen - 1; | |
97 | } else if (t->rx_buf) { | |
98 | /* | |
99 | * For receive-only transfers we still need to perform a dummy | |
100 | * write to receive data from the SPI chip. | |
101 | * Read data starts at the end of transmit data (minus 1 to | |
102 | * account for CS). | |
103 | */ | |
104 | hw->rindex = hw->tlen - 1; | |
105 | memset(&hw->buffer[hw->tlen], 0, len); | |
106 | hw->tlen += len; | |
107 | do_transfer = true; | |
108 | } | |
109 | ||
110 | if (do_transfer && hw->tlen > 1) { | |
111 | ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ); | |
112 | if (ret < 0) | |
113 | return ret; | |
114 | ret = i2c_master_send(hw->client, hw->buffer, hw->tlen); | |
115 | if (ret < 0) | |
116 | return ret; | |
117 | if (ret != hw->tlen) | |
118 | return -EIO; | |
119 | ||
120 | if (t->rx_buf) { | |
121 | int rlen = hw->rindex + len; | |
122 | ||
123 | ret = sc18is602_wait_ready(hw, hw->tlen); | |
124 | if (ret < 0) | |
125 | return ret; | |
126 | ret = i2c_master_recv(hw->client, hw->buffer, rlen); | |
127 | if (ret < 0) | |
128 | return ret; | |
129 | if (ret != rlen) | |
130 | return -EIO; | |
131 | memcpy(t->rx_buf, &hw->buffer[hw->rindex], len); | |
132 | } | |
133 | hw->tlen = 0; | |
134 | } | |
135 | return len; | |
136 | } | |
137 | ||
138 | static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode) | |
139 | { | |
140 | u8 ctrl = 0; | |
141 | int ret; | |
142 | ||
143 | if (mode & SPI_CPHA) | |
144 | ctrl |= SC18IS602_MODE_CPHA; | |
145 | if (mode & SPI_CPOL) | |
146 | ctrl |= SC18IS602_MODE_CPOL; | |
147 | if (mode & SPI_LSB_FIRST) | |
148 | ctrl |= SC18IS602_MODE_LSB_FIRST; | |
149 | ||
150 | /* Find the closest clock speed */ | |
151 | if (hz >= hw->freq / 4) { | |
152 | ctrl |= SC18IS602_MODE_CLOCK_DIV_4; | |
153 | hw->speed = hw->freq / 4; | |
154 | } else if (hz >= hw->freq / 16) { | |
155 | ctrl |= SC18IS602_MODE_CLOCK_DIV_16; | |
156 | hw->speed = hw->freq / 16; | |
157 | } else if (hz >= hw->freq / 64) { | |
158 | ctrl |= SC18IS602_MODE_CLOCK_DIV_64; | |
159 | hw->speed = hw->freq / 64; | |
160 | } else { | |
161 | ctrl |= SC18IS602_MODE_CLOCK_DIV_128; | |
162 | hw->speed = hw->freq / 128; | |
163 | } | |
164 | ||
165 | /* | |
166 | * Don't do anything if the control value did not change. The initial | |
167 | * value of 0xff for hw->ctrl ensures that the correct mode will be set | |
168 | * with the first call to this function. | |
169 | */ | |
170 | if (ctrl == hw->ctrl) | |
171 | return 0; | |
172 | ||
173 | ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl); | |
174 | if (ret < 0) | |
175 | return ret; | |
176 | ||
177 | hw->ctrl = ctrl; | |
178 | ||
179 | return 0; | |
180 | } | |
181 | ||
182 | static int sc18is602_check_transfer(struct spi_device *spi, | |
183 | struct spi_transfer *t, int tlen) | |
184 | { | |
3ce8859e GR |
185 | if (t && t->len + tlen > SC18IS602_BUFSIZ) |
186 | return -EINVAL; | |
187 | ||
3ce8859e GR |
188 | return 0; |
189 | } | |
190 | ||
191 | static int sc18is602_transfer_one(struct spi_master *master, | |
192 | struct spi_message *m) | |
193 | { | |
194 | struct sc18is602 *hw = spi_master_get_devdata(master); | |
195 | struct spi_device *spi = m->spi; | |
196 | struct spi_transfer *t; | |
197 | int status = 0; | |
198 | ||
3ce8859e GR |
199 | hw->tlen = 0; |
200 | list_for_each_entry(t, &m->transfers, transfer_list) { | |
3ce8859e GR |
201 | bool do_transfer; |
202 | ||
203 | status = sc18is602_check_transfer(spi, t, hw->tlen); | |
204 | if (status < 0) | |
205 | break; | |
206 | ||
09e99bca | 207 | status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode); |
3ce8859e GR |
208 | if (status < 0) |
209 | break; | |
210 | ||
211 | do_transfer = t->cs_change || list_is_last(&t->transfer_list, | |
212 | &m->transfers); | |
213 | ||
214 | if (t->len) { | |
215 | status = sc18is602_txrx(hw, m, t, do_transfer); | |
216 | if (status < 0) | |
217 | break; | |
218 | m->actual_length += status; | |
219 | } | |
220 | status = 0; | |
221 | ||
222 | if (t->delay_usecs) | |
223 | udelay(t->delay_usecs); | |
224 | } | |
3ce8859e GR |
225 | m->status = status; |
226 | spi_finalize_current_message(master); | |
227 | ||
228 | return status; | |
229 | } | |
230 | ||
c5c67e31 AL |
231 | static int sc18is602_setup(struct spi_device *spi) |
232 | { | |
233 | struct sc18is602 *hw = spi_master_get_devdata(spi->master); | |
234 | ||
235 | /* SC18IS602 does not support CS2 */ | |
236 | if (hw->id == sc18is602 && spi->chip_select == 2) | |
237 | return -ENXIO; | |
238 | ||
239 | return 0; | |
240 | } | |
241 | ||
3ce8859e GR |
242 | static int sc18is602_probe(struct i2c_client *client, |
243 | const struct i2c_device_id *id) | |
244 | { | |
245 | struct device *dev = &client->dev; | |
246 | struct device_node *np = dev->of_node; | |
247 | struct sc18is602_platform_data *pdata = dev_get_platdata(dev); | |
248 | struct sc18is602 *hw; | |
249 | struct spi_master *master; | |
250 | int error; | |
251 | ||
252 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | | |
253 | I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) | |
58ed90de | 254 | return -EINVAL; |
3ce8859e GR |
255 | |
256 | master = spi_alloc_master(dev, sizeof(struct sc18is602)); | |
257 | if (!master) | |
258 | return -ENOMEM; | |
259 | ||
260 | hw = spi_master_get_devdata(master); | |
261 | i2c_set_clientdata(client, hw); | |
262 | ||
f9900801 PR |
263 | /* assert reset and then release */ |
264 | hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); | |
265 | if (IS_ERR(hw->reset)) | |
266 | return PTR_ERR(hw->reset); | |
267 | gpiod_set_value(hw->reset, 0); | |
268 | ||
3ce8859e GR |
269 | hw->master = master; |
270 | hw->client = client; | |
271 | hw->dev = dev; | |
272 | hw->ctrl = 0xff; | |
273 | ||
274 | hw->id = id->driver_data; | |
275 | ||
276 | switch (hw->id) { | |
277 | case sc18is602: | |
278 | case sc18is602b: | |
279 | master->num_chipselect = 4; | |
280 | hw->freq = SC18IS602_CLOCK; | |
281 | break; | |
282 | case sc18is603: | |
283 | master->num_chipselect = 2; | |
284 | if (pdata) { | |
285 | hw->freq = pdata->clock_frequency; | |
286 | } else { | |
287 | const __be32 *val; | |
288 | int len; | |
289 | ||
290 | val = of_get_property(np, "clock-frequency", &len); | |
291 | if (val && len >= sizeof(__be32)) | |
292 | hw->freq = be32_to_cpup(val); | |
293 | } | |
294 | if (!hw->freq) | |
295 | hw->freq = SC18IS602_CLOCK; | |
296 | break; | |
297 | } | |
b4e27545 | 298 | master->bus_num = np ? -1 : client->adapter->nr; |
3ce8859e | 299 | master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST; |
463654ce | 300 | master->bits_per_word_mask = SPI_BPW_MASK(8); |
c5c67e31 | 301 | master->setup = sc18is602_setup; |
3ce8859e GR |
302 | master->transfer_one_message = sc18is602_transfer_one; |
303 | master->dev.of_node = np; | |
09e99bca AL |
304 | master->min_speed_hz = hw->freq / 128; |
305 | master->max_speed_hz = hw->freq / 4; | |
3ce8859e | 306 | |
15e0964d | 307 | error = devm_spi_register_master(dev, master); |
3ce8859e GR |
308 | if (error) |
309 | goto error_reg; | |
310 | ||
311 | return 0; | |
312 | ||
313 | error_reg: | |
314 | spi_master_put(master); | |
315 | return error; | |
316 | } | |
317 | ||
3ce8859e GR |
318 | static const struct i2c_device_id sc18is602_id[] = { |
319 | { "sc18is602", sc18is602 }, | |
320 | { "sc18is602b", sc18is602b }, | |
321 | { "sc18is603", sc18is603 }, | |
322 | { } | |
323 | }; | |
324 | MODULE_DEVICE_TABLE(i2c, sc18is602_id); | |
325 | ||
326 | static struct i2c_driver sc18is602_driver = { | |
327 | .driver = { | |
328 | .name = "sc18is602", | |
329 | }, | |
330 | .probe = sc18is602_probe, | |
3ce8859e GR |
331 | .id_table = sc18is602_id, |
332 | }; | |
333 | ||
334 | module_i2c_driver(sc18is602_driver); | |
335 | ||
336 | MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver"); | |
337 | MODULE_AUTHOR("Guenter Roeck"); | |
338 | MODULE_LICENSE("GPL"); |