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8#include <linux/kernel.h>
9#include <linux/err.h>
10#include <linux/module.h>
11#include <linux/spi/spi.h>
12#include <linux/i2c.h>
13#include <linux/delay.h>
14#include <linux/pm_runtime.h>
15#include <linux/of_device.h>
16#include <linux/of.h>
17#include <linux/platform_data/sc18is602.h>
18#include <linux/gpio/consumer.h>
19
20enum chips { sc18is602, sc18is602b, sc18is603 };
21
22#define SC18IS602_BUFSIZ 200
23#define SC18IS602_CLOCK 7372000
24
25#define SC18IS602_MODE_CPHA BIT(2)
26#define SC18IS602_MODE_CPOL BIT(3)
27#define SC18IS602_MODE_LSB_FIRST BIT(5)
28#define SC18IS602_MODE_CLOCK_DIV_4 0x0
29#define SC18IS602_MODE_CLOCK_DIV_16 0x1
30#define SC18IS602_MODE_CLOCK_DIV_64 0x2
31#define SC18IS602_MODE_CLOCK_DIV_128 0x3
32
33struct sc18is602 {
34 struct spi_master *master;
35 struct device *dev;
36 u8 ctrl;
37 u32 freq;
38 u32 speed;
39
40
41 struct i2c_client *client;
42 enum chips id;
43 u8 buffer[SC18IS602_BUFSIZ + 1];
44 int tlen;
45 int rindex;
46
47 struct gpio_desc *reset;
48};
49
50static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
51{
52 int i, err;
53 int usecs = 1000000 * len / hw->speed + 1;
54 u8 dummy[1];
55
56 for (i = 0; i < 10; i++) {
57 err = i2c_master_recv(hw->client, dummy, 1);
58 if (err >= 0)
59 return 0;
60 usleep_range(usecs, usecs * 2);
61 }
62 return -ETIMEDOUT;
63}
64
65static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
66 struct spi_transfer *t, bool do_transfer)
67{
68 unsigned int len = t->len;
69 int ret;
70
71 if (hw->tlen == 0) {
72
73 hw->buffer[0] = 1 << msg->spi->chip_select;
74 hw->tlen = 1;
75 hw->rindex = 0;
76 }
77
78
79
80
81
82 if (t->tx_buf) {
83 memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
84 hw->tlen += len;
85 if (t->rx_buf)
86 do_transfer = true;
87 else
88 hw->rindex = hw->tlen - 1;
89 } else if (t->rx_buf) {
90
91
92
93
94
95
96 hw->rindex = hw->tlen - 1;
97 memset(&hw->buffer[hw->tlen], 0, len);
98 hw->tlen += len;
99 do_transfer = true;
100 }
101
102 if (do_transfer && hw->tlen > 1) {
103 ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
104 if (ret < 0)
105 return ret;
106 ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
107 if (ret < 0)
108 return ret;
109 if (ret != hw->tlen)
110 return -EIO;
111
112 if (t->rx_buf) {
113 int rlen = hw->rindex + len;
114
115 ret = sc18is602_wait_ready(hw, hw->tlen);
116 if (ret < 0)
117 return ret;
118 ret = i2c_master_recv(hw->client, hw->buffer, rlen);
119 if (ret < 0)
120 return ret;
121 if (ret != rlen)
122 return -EIO;
123 memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
124 }
125 hw->tlen = 0;
126 }
127 return len;
128}
129
130static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
131{
132 u8 ctrl = 0;
133 int ret;
134
135 if (mode & SPI_CPHA)
136 ctrl |= SC18IS602_MODE_CPHA;
137 if (mode & SPI_CPOL)
138 ctrl |= SC18IS602_MODE_CPOL;
139 if (mode & SPI_LSB_FIRST)
140 ctrl |= SC18IS602_MODE_LSB_FIRST;
141
142
143 if (hz >= hw->freq / 4) {
144 ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
145 hw->speed = hw->freq / 4;
146 } else if (hz >= hw->freq / 16) {
147 ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
148 hw->speed = hw->freq / 16;
149 } else if (hz >= hw->freq / 64) {
150 ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
151 hw->speed = hw->freq / 64;
152 } else {
153 ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
154 hw->speed = hw->freq / 128;
155 }
156
157
158
159
160
161
162 if (ctrl == hw->ctrl)
163 return 0;
164
165 ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
166 if (ret < 0)
167 return ret;
168
169 hw->ctrl = ctrl;
170
171 return 0;
172}
173
174static int sc18is602_check_transfer(struct spi_device *spi,
175 struct spi_transfer *t, int tlen)
176{
177 if (t && t->len + tlen > SC18IS602_BUFSIZ)
178 return -EINVAL;
179
180 return 0;
181}
182
183static int sc18is602_transfer_one(struct spi_master *master,
184 struct spi_message *m)
185{
186 struct sc18is602 *hw = spi_master_get_devdata(master);
187 struct spi_device *spi = m->spi;
188 struct spi_transfer *t;
189 int status = 0;
190
191 hw->tlen = 0;
192 list_for_each_entry(t, &m->transfers, transfer_list) {
193 bool do_transfer;
194
195 status = sc18is602_check_transfer(spi, t, hw->tlen);
196 if (status < 0)
197 break;
198
199 status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
200 if (status < 0)
201 break;
202
203 do_transfer = t->cs_change || list_is_last(&t->transfer_list,
204 &m->transfers);
205
206 if (t->len) {
207 status = sc18is602_txrx(hw, m, t, do_transfer);
208 if (status < 0)
209 break;
210 m->actual_length += status;
211 }
212 status = 0;
213
214 spi_transfer_delay_exec(t);
215 }
216 m->status = status;
217 spi_finalize_current_message(master);
218
219 return status;
220}
221
222static int sc18is602_setup(struct spi_device *spi)
223{
224 struct sc18is602 *hw = spi_master_get_devdata(spi->master);
225
226
227 if (hw->id == sc18is602 && spi->chip_select == 2)
228 return -ENXIO;
229
230 return 0;
231}
232
233static int sc18is602_probe(struct i2c_client *client,
234 const struct i2c_device_id *id)
235{
236 struct device *dev = &client->dev;
237 struct device_node *np = dev->of_node;
238 struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
239 struct sc18is602 *hw;
240 struct spi_master *master;
241 int error;
242
243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
244 I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
245 return -EINVAL;
246
247 master = spi_alloc_master(dev, sizeof(struct sc18is602));
248 if (!master)
249 return -ENOMEM;
250
251 hw = spi_master_get_devdata(master);
252 i2c_set_clientdata(client, hw);
253
254
255 hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
256 if (IS_ERR(hw->reset))
257 return PTR_ERR(hw->reset);
258 gpiod_set_value_cansleep(hw->reset, 0);
259
260 hw->master = master;
261 hw->client = client;
262 hw->dev = dev;
263 hw->ctrl = 0xff;
264
265 if (client->dev.of_node)
266 hw->id = (enum chips)of_device_get_match_data(&client->dev);
267 else
268 hw->id = id->driver_data;
269
270 switch (hw->id) {
271 case sc18is602:
272 case sc18is602b:
273 master->num_chipselect = 4;
274 hw->freq = SC18IS602_CLOCK;
275 break;
276 case sc18is603:
277 master->num_chipselect = 2;
278 if (pdata) {
279 hw->freq = pdata->clock_frequency;
280 } else {
281 const __be32 *val;
282 int len;
283
284 val = of_get_property(np, "clock-frequency", &len);
285 if (val && len >= sizeof(__be32))
286 hw->freq = be32_to_cpup(val);
287 }
288 if (!hw->freq)
289 hw->freq = SC18IS602_CLOCK;
290 break;
291 }
292 master->bus_num = np ? -1 : client->adapter->nr;
293 master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
294 master->bits_per_word_mask = SPI_BPW_MASK(8);
295 master->setup = sc18is602_setup;
296 master->transfer_one_message = sc18is602_transfer_one;
297 master->dev.of_node = np;
298 master->min_speed_hz = hw->freq / 128;
299 master->max_speed_hz = hw->freq / 4;
300
301 error = devm_spi_register_master(dev, master);
302 if (error)
303 goto error_reg;
304
305 return 0;
306
307error_reg:
308 spi_master_put(master);
309 return error;
310}
311
312static const struct i2c_device_id sc18is602_id[] = {
313 { "sc18is602", sc18is602 },
314 { "sc18is602b", sc18is602b },
315 { "sc18is603", sc18is603 },
316 { }
317};
318MODULE_DEVICE_TABLE(i2c, sc18is602_id);
319
320static const struct of_device_id sc18is602_of_match[] = {
321 {
322 .compatible = "nxp,sc18is602",
323 .data = (void *)sc18is602
324 },
325 {
326 .compatible = "nxp,sc18is602b",
327 .data = (void *)sc18is602b
328 },
329 {
330 .compatible = "nxp,sc18is603",
331 .data = (void *)sc18is603
332 },
333 { },
334};
335MODULE_DEVICE_TABLE(of, sc18is602_of_match);
336
337static struct i2c_driver sc18is602_driver = {
338 .driver = {
339 .name = "sc18is602",
340 .of_match_table = of_match_ptr(sc18is602_of_match),
341 },
342 .probe = sc18is602_probe,
343 .id_table = sc18is602_id,
344};
345
346module_i2c_driver(sc18is602_driver);
347
348MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
349MODULE_AUTHOR("Guenter Roeck");
350MODULE_LICENSE("GPL");
351
