Commit | Line | Data |
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ce792580 TC |
1 | /* |
2 | * OpenCores tiny SPI master driver | |
3 | * | |
4 | * http://opencores.org/project,tiny_spi | |
5 | * | |
6 | * Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw> | |
7 | * | |
8 | * Based on spi_s3c24xx.c, which is: | |
9 | * Copyright (c) 2006 Ben Dooks | |
10 | * Copyright (c) 2006 Simtec Electronics | |
11 | * Ben Dooks <ben@simtec.co.uk> | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License version 2 as | |
15 | * published by the Free Software Foundation. | |
16 | */ | |
17 | ||
18 | #include <linux/init.h> | |
19 | #include <linux/interrupt.h> | |
20 | #include <linux/errno.h> | |
d7614de4 | 21 | #include <linux/module.h> |
ce792580 TC |
22 | #include <linux/platform_device.h> |
23 | #include <linux/spi/spi.h> | |
24 | #include <linux/spi/spi_bitbang.h> | |
25 | #include <linux/spi/spi_oc_tiny.h> | |
26 | #include <linux/io.h> | |
27 | #include <linux/gpio.h> | |
28 | #include <linux/of.h> | |
29 | ||
30 | #define DRV_NAME "spi_oc_tiny" | |
31 | ||
32 | #define TINY_SPI_RXDATA 0 | |
33 | #define TINY_SPI_TXDATA 4 | |
34 | #define TINY_SPI_STATUS 8 | |
35 | #define TINY_SPI_CONTROL 12 | |
36 | #define TINY_SPI_BAUD 16 | |
37 | ||
38 | #define TINY_SPI_STATUS_TXE 0x1 | |
39 | #define TINY_SPI_STATUS_TXR 0x2 | |
40 | ||
41 | struct tiny_spi { | |
42 | /* bitbang has to be first */ | |
43 | struct spi_bitbang bitbang; | |
44 | struct completion done; | |
45 | ||
46 | void __iomem *base; | |
47 | int irq; | |
48 | unsigned int freq; | |
49 | unsigned int baudwidth; | |
50 | unsigned int baud; | |
51 | unsigned int speed_hz; | |
52 | unsigned int mode; | |
53 | unsigned int len; | |
54 | unsigned int txc, rxc; | |
55 | const u8 *txp; | |
56 | u8 *rxp; | |
e80beb27 | 57 | int gpio_cs_count; |
ce792580 TC |
58 | int *gpio_cs; |
59 | }; | |
60 | ||
61 | static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev) | |
62 | { | |
63 | return spi_master_get_devdata(sdev->master); | |
64 | } | |
65 | ||
66 | static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz) | |
67 | { | |
68 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
69 | ||
70 | return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1; | |
71 | } | |
72 | ||
73 | static void tiny_spi_chipselect(struct spi_device *spi, int is_active) | |
74 | { | |
75 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
76 | ||
e80beb27 | 77 | if (hw->gpio_cs_count > 0) { |
ce792580 TC |
78 | gpio_set_value(hw->gpio_cs[spi->chip_select], |
79 | (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); | |
80 | } | |
81 | } | |
82 | ||
83 | static int tiny_spi_setup_transfer(struct spi_device *spi, | |
84 | struct spi_transfer *t) | |
85 | { | |
86 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
87 | unsigned int baud = hw->baud; | |
88 | ||
89 | if (t) { | |
90 | if (t->speed_hz && t->speed_hz != hw->speed_hz) | |
91 | baud = tiny_spi_baud(spi, t->speed_hz); | |
92 | } | |
93 | writel(baud, hw->base + TINY_SPI_BAUD); | |
94 | writel(hw->mode, hw->base + TINY_SPI_CONTROL); | |
95 | return 0; | |
96 | } | |
97 | ||
98 | static int tiny_spi_setup(struct spi_device *spi) | |
99 | { | |
100 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
101 | ||
102 | if (spi->max_speed_hz != hw->speed_hz) { | |
103 | hw->speed_hz = spi->max_speed_hz; | |
104 | hw->baud = tiny_spi_baud(spi, hw->speed_hz); | |
105 | } | |
106 | hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static inline void tiny_spi_wait_txr(struct tiny_spi *hw) | |
111 | { | |
112 | while (!(readb(hw->base + TINY_SPI_STATUS) & | |
113 | TINY_SPI_STATUS_TXR)) | |
114 | cpu_relax(); | |
115 | } | |
116 | ||
117 | static inline void tiny_spi_wait_txe(struct tiny_spi *hw) | |
118 | { | |
119 | while (!(readb(hw->base + TINY_SPI_STATUS) & | |
120 | TINY_SPI_STATUS_TXE)) | |
121 | cpu_relax(); | |
122 | } | |
123 | ||
124 | static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) | |
125 | { | |
126 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
127 | const u8 *txp = t->tx_buf; | |
128 | u8 *rxp = t->rx_buf; | |
129 | unsigned int i; | |
130 | ||
131 | if (hw->irq >= 0) { | |
886db6ac | 132 | /* use interrupt driven data transfer */ |
ce792580 TC |
133 | hw->len = t->len; |
134 | hw->txp = t->tx_buf; | |
135 | hw->rxp = t->rx_buf; | |
136 | hw->txc = 0; | |
137 | hw->rxc = 0; | |
138 | ||
139 | /* send the first byte */ | |
140 | if (t->len > 1) { | |
141 | writeb(hw->txp ? *hw->txp++ : 0, | |
142 | hw->base + TINY_SPI_TXDATA); | |
143 | hw->txc++; | |
144 | writeb(hw->txp ? *hw->txp++ : 0, | |
145 | hw->base + TINY_SPI_TXDATA); | |
146 | hw->txc++; | |
147 | writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS); | |
148 | } else { | |
149 | writeb(hw->txp ? *hw->txp++ : 0, | |
150 | hw->base + TINY_SPI_TXDATA); | |
151 | hw->txc++; | |
152 | writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS); | |
153 | } | |
154 | ||
155 | wait_for_completion(&hw->done); | |
156 | } else if (txp && rxp) { | |
157 | /* we need to tighten the transfer loop */ | |
158 | writeb(*txp++, hw->base + TINY_SPI_TXDATA); | |
159 | if (t->len > 1) { | |
160 | writeb(*txp++, hw->base + TINY_SPI_TXDATA); | |
161 | for (i = 2; i < t->len; i++) { | |
162 | u8 rx, tx = *txp++; | |
163 | tiny_spi_wait_txr(hw); | |
164 | rx = readb(hw->base + TINY_SPI_TXDATA); | |
165 | writeb(tx, hw->base + TINY_SPI_TXDATA); | |
166 | *rxp++ = rx; | |
167 | } | |
168 | tiny_spi_wait_txr(hw); | |
169 | *rxp++ = readb(hw->base + TINY_SPI_TXDATA); | |
170 | } | |
171 | tiny_spi_wait_txe(hw); | |
172 | *rxp++ = readb(hw->base + TINY_SPI_RXDATA); | |
173 | } else if (rxp) { | |
174 | writeb(0, hw->base + TINY_SPI_TXDATA); | |
175 | if (t->len > 1) { | |
176 | writeb(0, | |
177 | hw->base + TINY_SPI_TXDATA); | |
178 | for (i = 2; i < t->len; i++) { | |
179 | u8 rx; | |
180 | tiny_spi_wait_txr(hw); | |
181 | rx = readb(hw->base + TINY_SPI_TXDATA); | |
182 | writeb(0, hw->base + TINY_SPI_TXDATA); | |
183 | *rxp++ = rx; | |
184 | } | |
185 | tiny_spi_wait_txr(hw); | |
186 | *rxp++ = readb(hw->base + TINY_SPI_TXDATA); | |
187 | } | |
188 | tiny_spi_wait_txe(hw); | |
189 | *rxp++ = readb(hw->base + TINY_SPI_RXDATA); | |
190 | } else if (txp) { | |
191 | writeb(*txp++, hw->base + TINY_SPI_TXDATA); | |
192 | if (t->len > 1) { | |
193 | writeb(*txp++, hw->base + TINY_SPI_TXDATA); | |
194 | for (i = 2; i < t->len; i++) { | |
195 | u8 tx = *txp++; | |
196 | tiny_spi_wait_txr(hw); | |
197 | writeb(tx, hw->base + TINY_SPI_TXDATA); | |
198 | } | |
199 | } | |
200 | tiny_spi_wait_txe(hw); | |
201 | } else { | |
202 | writeb(0, hw->base + TINY_SPI_TXDATA); | |
203 | if (t->len > 1) { | |
204 | writeb(0, hw->base + TINY_SPI_TXDATA); | |
205 | for (i = 2; i < t->len; i++) { | |
206 | tiny_spi_wait_txr(hw); | |
207 | writeb(0, hw->base + TINY_SPI_TXDATA); | |
208 | } | |
209 | } | |
210 | tiny_spi_wait_txe(hw); | |
211 | } | |
212 | return t->len; | |
213 | } | |
214 | ||
215 | static irqreturn_t tiny_spi_irq(int irq, void *dev) | |
216 | { | |
217 | struct tiny_spi *hw = dev; | |
218 | ||
219 | writeb(0, hw->base + TINY_SPI_STATUS); | |
220 | if (hw->rxc + 1 == hw->len) { | |
221 | if (hw->rxp) | |
222 | *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA); | |
223 | hw->rxc++; | |
224 | complete(&hw->done); | |
225 | } else { | |
226 | if (hw->rxp) | |
227 | *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA); | |
228 | hw->rxc++; | |
229 | if (hw->txc < hw->len) { | |
230 | writeb(hw->txp ? *hw->txp++ : 0, | |
231 | hw->base + TINY_SPI_TXDATA); | |
232 | hw->txc++; | |
233 | writeb(TINY_SPI_STATUS_TXR, | |
234 | hw->base + TINY_SPI_STATUS); | |
235 | } else { | |
236 | writeb(TINY_SPI_STATUS_TXE, | |
237 | hw->base + TINY_SPI_STATUS); | |
238 | } | |
239 | } | |
240 | return IRQ_HANDLED; | |
241 | } | |
242 | ||
243 | #ifdef CONFIG_OF | |
244 | #include <linux/of_gpio.h> | |
245 | ||
fd4a319b | 246 | static int tiny_spi_of_probe(struct platform_device *pdev) |
ce792580 TC |
247 | { |
248 | struct tiny_spi *hw = platform_get_drvdata(pdev); | |
249 | struct device_node *np = pdev->dev.of_node; | |
250 | unsigned int i; | |
251 | const __be32 *val; | |
252 | int len; | |
253 | ||
254 | if (!np) | |
255 | return 0; | |
256 | hw->gpio_cs_count = of_gpio_count(np); | |
e80beb27 | 257 | if (hw->gpio_cs_count > 0) { |
ce792580 TC |
258 | hw->gpio_cs = devm_kzalloc(&pdev->dev, |
259 | hw->gpio_cs_count * sizeof(unsigned int), | |
260 | GFP_KERNEL); | |
261 | if (!hw->gpio_cs) | |
262 | return -ENOMEM; | |
263 | } | |
264 | for (i = 0; i < hw->gpio_cs_count; i++) { | |
265 | hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL); | |
266 | if (hw->gpio_cs[i] < 0) | |
267 | return -ENODEV; | |
268 | } | |
269 | hw->bitbang.master->dev.of_node = pdev->dev.of_node; | |
270 | val = of_get_property(pdev->dev.of_node, | |
271 | "clock-frequency", &len); | |
272 | if (val && len >= sizeof(__be32)) | |
273 | hw->freq = be32_to_cpup(val); | |
274 | val = of_get_property(pdev->dev.of_node, "baud-width", &len); | |
275 | if (val && len >= sizeof(__be32)) | |
276 | hw->baudwidth = be32_to_cpup(val); | |
277 | return 0; | |
278 | } | |
279 | #else /* !CONFIG_OF */ | |
fd4a319b | 280 | static int tiny_spi_of_probe(struct platform_device *pdev) |
ce792580 TC |
281 | { |
282 | return 0; | |
283 | } | |
284 | #endif /* CONFIG_OF */ | |
285 | ||
fd4a319b | 286 | static int tiny_spi_probe(struct platform_device *pdev) |
ce792580 | 287 | { |
8074cf06 | 288 | struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev); |
ce792580 TC |
289 | struct tiny_spi *hw; |
290 | struct spi_master *master; | |
291 | struct resource *res; | |
292 | unsigned int i; | |
293 | int err = -ENODEV; | |
294 | ||
295 | master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi)); | |
296 | if (!master) | |
297 | return err; | |
298 | ||
299 | /* setup the master state. */ | |
300 | master->bus_num = pdev->id; | |
301 | master->num_chipselect = 255; | |
302 | master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; | |
303 | master->setup = tiny_spi_setup; | |
304 | ||
305 | hw = spi_master_get_devdata(master); | |
306 | platform_set_drvdata(pdev, hw); | |
307 | ||
308 | /* setup the state for the bitbang driver */ | |
309 | hw->bitbang.master = spi_master_get(master); | |
310 | if (!hw->bitbang.master) | |
311 | return err; | |
312 | hw->bitbang.setup_transfer = tiny_spi_setup_transfer; | |
313 | hw->bitbang.chipselect = tiny_spi_chipselect; | |
314 | hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs; | |
315 | ||
316 | /* find and map our resources */ | |
317 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
b3136f8f JL |
318 | hw->base = devm_ioremap_resource(&pdev->dev, res); |
319 | if (IS_ERR(hw->base)) { | |
320 | err = PTR_ERR(hw->base); | |
321 | goto exit; | |
322 | } | |
ce792580 TC |
323 | /* irq is optional */ |
324 | hw->irq = platform_get_irq(pdev, 0); | |
325 | if (hw->irq >= 0) { | |
326 | init_completion(&hw->done); | |
327 | err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0, | |
328 | pdev->name, hw); | |
329 | if (err) | |
330 | goto exit; | |
331 | } | |
332 | /* find platform data */ | |
333 | if (platp) { | |
334 | hw->gpio_cs_count = platp->gpio_cs_count; | |
335 | hw->gpio_cs = platp->gpio_cs; | |
b3136f8f JL |
336 | if (platp->gpio_cs_count && !platp->gpio_cs) { |
337 | err = -EBUSY; | |
338 | goto exit; | |
339 | } | |
ce792580 TC |
340 | hw->freq = platp->freq; |
341 | hw->baudwidth = platp->baudwidth; | |
342 | } else { | |
343 | err = tiny_spi_of_probe(pdev); | |
344 | if (err) | |
345 | goto exit; | |
346 | } | |
347 | for (i = 0; i < hw->gpio_cs_count; i++) { | |
348 | err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev)); | |
349 | if (err) | |
350 | goto exit_gpio; | |
351 | gpio_direction_output(hw->gpio_cs[i], 1); | |
352 | } | |
e80beb27 | 353 | hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count); |
ce792580 TC |
354 | |
355 | /* register our spi controller */ | |
356 | err = spi_bitbang_start(&hw->bitbang); | |
357 | if (err) | |
358 | goto exit; | |
359 | dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); | |
360 | ||
361 | return 0; | |
362 | ||
363 | exit_gpio: | |
364 | while (i-- > 0) | |
365 | gpio_free(hw->gpio_cs[i]); | |
ce792580 | 366 | exit: |
ce792580 TC |
367 | spi_master_put(master); |
368 | return err; | |
369 | } | |
370 | ||
fd4a319b | 371 | static int tiny_spi_remove(struct platform_device *pdev) |
ce792580 TC |
372 | { |
373 | struct tiny_spi *hw = platform_get_drvdata(pdev); | |
374 | struct spi_master *master = hw->bitbang.master; | |
375 | unsigned int i; | |
376 | ||
377 | spi_bitbang_stop(&hw->bitbang); | |
378 | for (i = 0; i < hw->gpio_cs_count; i++) | |
379 | gpio_free(hw->gpio_cs[i]); | |
ce792580 TC |
380 | spi_master_put(master); |
381 | return 0; | |
382 | } | |
383 | ||
384 | #ifdef CONFIG_OF | |
385 | static const struct of_device_id tiny_spi_match[] = { | |
386 | { .compatible = "opencores,tiny-spi-rtlsvn2", }, | |
387 | {}, | |
388 | }; | |
389 | MODULE_DEVICE_TABLE(of, tiny_spi_match); | |
ce792580 TC |
390 | #endif /* CONFIG_OF */ |
391 | ||
392 | static struct platform_driver tiny_spi_driver = { | |
393 | .probe = tiny_spi_probe, | |
fd4a319b | 394 | .remove = tiny_spi_remove, |
ce792580 TC |
395 | .driver = { |
396 | .name = DRV_NAME, | |
397 | .owner = THIS_MODULE, | |
398 | .pm = NULL, | |
9547acce | 399 | .of_match_table = of_match_ptr(tiny_spi_match), |
ce792580 TC |
400 | }, |
401 | }; | |
940ab889 | 402 | module_platform_driver(tiny_spi_driver); |
ce792580 TC |
403 | |
404 | MODULE_DESCRIPTION("OpenCores tiny SPI driver"); | |
405 | MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); | |
406 | MODULE_LICENSE("GPL"); | |
407 | MODULE_ALIAS("platform:" DRV_NAME); |