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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 | ||
ce792580 TC |
18 | #include <linux/interrupt.h> |
19 | #include <linux/errno.h> | |
d7614de4 | 20 | #include <linux/module.h> |
ce792580 TC |
21 | #include <linux/platform_device.h> |
22 | #include <linux/spi/spi.h> | |
23 | #include <linux/spi/spi_bitbang.h> | |
24 | #include <linux/spi/spi_oc_tiny.h> | |
25 | #include <linux/io.h> | |
26 | #include <linux/gpio.h> | |
27 | #include <linux/of.h> | |
28 | ||
29 | #define DRV_NAME "spi_oc_tiny" | |
30 | ||
31 | #define TINY_SPI_RXDATA 0 | |
32 | #define TINY_SPI_TXDATA 4 | |
33 | #define TINY_SPI_STATUS 8 | |
34 | #define TINY_SPI_CONTROL 12 | |
35 | #define TINY_SPI_BAUD 16 | |
36 | ||
37 | #define TINY_SPI_STATUS_TXE 0x1 | |
38 | #define TINY_SPI_STATUS_TXR 0x2 | |
39 | ||
40 | struct tiny_spi { | |
41 | /* bitbang has to be first */ | |
42 | struct spi_bitbang bitbang; | |
43 | struct completion done; | |
44 | ||
45 | void __iomem *base; | |
46 | int irq; | |
47 | unsigned int freq; | |
48 | unsigned int baudwidth; | |
49 | unsigned int baud; | |
50 | unsigned int speed_hz; | |
51 | unsigned int mode; | |
52 | unsigned int len; | |
53 | unsigned int txc, rxc; | |
54 | const u8 *txp; | |
55 | u8 *rxp; | |
e80beb27 | 56 | int gpio_cs_count; |
ce792580 TC |
57 | int *gpio_cs; |
58 | }; | |
59 | ||
60 | static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev) | |
61 | { | |
62 | return spi_master_get_devdata(sdev->master); | |
63 | } | |
64 | ||
65 | static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz) | |
66 | { | |
67 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
68 | ||
69 | return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1; | |
70 | } | |
71 | ||
72 | static void tiny_spi_chipselect(struct spi_device *spi, int is_active) | |
73 | { | |
74 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
75 | ||
e80beb27 | 76 | if (hw->gpio_cs_count > 0) { |
ce792580 TC |
77 | gpio_set_value(hw->gpio_cs[spi->chip_select], |
78 | (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); | |
79 | } | |
80 | } | |
81 | ||
82 | static int tiny_spi_setup_transfer(struct spi_device *spi, | |
83 | struct spi_transfer *t) | |
84 | { | |
85 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
86 | unsigned int baud = hw->baud; | |
87 | ||
88 | if (t) { | |
89 | if (t->speed_hz && t->speed_hz != hw->speed_hz) | |
90 | baud = tiny_spi_baud(spi, t->speed_hz); | |
91 | } | |
92 | writel(baud, hw->base + TINY_SPI_BAUD); | |
93 | writel(hw->mode, hw->base + TINY_SPI_CONTROL); | |
94 | return 0; | |
95 | } | |
96 | ||
97 | static int tiny_spi_setup(struct spi_device *spi) | |
98 | { | |
99 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
100 | ||
101 | if (spi->max_speed_hz != hw->speed_hz) { | |
102 | hw->speed_hz = spi->max_speed_hz; | |
103 | hw->baud = tiny_spi_baud(spi, hw->speed_hz); | |
104 | } | |
105 | hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA); | |
106 | return 0; | |
107 | } | |
108 | ||
109 | static inline void tiny_spi_wait_txr(struct tiny_spi *hw) | |
110 | { | |
111 | while (!(readb(hw->base + TINY_SPI_STATUS) & | |
112 | TINY_SPI_STATUS_TXR)) | |
113 | cpu_relax(); | |
114 | } | |
115 | ||
116 | static inline void tiny_spi_wait_txe(struct tiny_spi *hw) | |
117 | { | |
118 | while (!(readb(hw->base + TINY_SPI_STATUS) & | |
119 | TINY_SPI_STATUS_TXE)) | |
120 | cpu_relax(); | |
121 | } | |
122 | ||
123 | static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) | |
124 | { | |
125 | struct tiny_spi *hw = tiny_spi_to_hw(spi); | |
126 | const u8 *txp = t->tx_buf; | |
127 | u8 *rxp = t->rx_buf; | |
128 | unsigned int i; | |
129 | ||
130 | if (hw->irq >= 0) { | |
886db6ac | 131 | /* use interrupt driven data transfer */ |
ce792580 TC |
132 | hw->len = t->len; |
133 | hw->txp = t->tx_buf; | |
134 | hw->rxp = t->rx_buf; | |
135 | hw->txc = 0; | |
136 | hw->rxc = 0; | |
137 | ||
138 | /* send the first byte */ | |
139 | if (t->len > 1) { | |
140 | writeb(hw->txp ? *hw->txp++ : 0, | |
141 | hw->base + TINY_SPI_TXDATA); | |
142 | hw->txc++; | |
143 | writeb(hw->txp ? *hw->txp++ : 0, | |
144 | hw->base + TINY_SPI_TXDATA); | |
145 | hw->txc++; | |
146 | writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS); | |
147 | } else { | |
148 | writeb(hw->txp ? *hw->txp++ : 0, | |
149 | hw->base + TINY_SPI_TXDATA); | |
150 | hw->txc++; | |
151 | writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS); | |
152 | } | |
153 | ||
154 | wait_for_completion(&hw->done); | |
ce792580 | 155 | } else { |
e826a7ff AL |
156 | /* we need to tighten the transfer loop */ |
157 | writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA); | |
158 | for (i = 1; i < t->len; i++) { | |
159 | writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA); | |
160 | ||
161 | if (rxp || (i != t->len - 1)) | |
ce792580 | 162 | tiny_spi_wait_txr(hw); |
e826a7ff AL |
163 | if (rxp) |
164 | *rxp++ = readb(hw->base + TINY_SPI_TXDATA); | |
ce792580 TC |
165 | } |
166 | tiny_spi_wait_txe(hw); | |
e826a7ff AL |
167 | if (rxp) |
168 | *rxp++ = readb(hw->base + TINY_SPI_RXDATA); | |
ce792580 | 169 | } |
e826a7ff | 170 | |
ce792580 TC |
171 | return t->len; |
172 | } | |
173 | ||
174 | static irqreturn_t tiny_spi_irq(int irq, void *dev) | |
175 | { | |
176 | struct tiny_spi *hw = dev; | |
177 | ||
178 | writeb(0, hw->base + TINY_SPI_STATUS); | |
179 | if (hw->rxc + 1 == hw->len) { | |
180 | if (hw->rxp) | |
181 | *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA); | |
182 | hw->rxc++; | |
183 | complete(&hw->done); | |
184 | } else { | |
185 | if (hw->rxp) | |
186 | *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA); | |
187 | hw->rxc++; | |
188 | if (hw->txc < hw->len) { | |
189 | writeb(hw->txp ? *hw->txp++ : 0, | |
190 | hw->base + TINY_SPI_TXDATA); | |
191 | hw->txc++; | |
192 | writeb(TINY_SPI_STATUS_TXR, | |
193 | hw->base + TINY_SPI_STATUS); | |
194 | } else { | |
195 | writeb(TINY_SPI_STATUS_TXE, | |
196 | hw->base + TINY_SPI_STATUS); | |
197 | } | |
198 | } | |
199 | return IRQ_HANDLED; | |
200 | } | |
201 | ||
202 | #ifdef CONFIG_OF | |
203 | #include <linux/of_gpio.h> | |
204 | ||
fd4a319b | 205 | static int tiny_spi_of_probe(struct platform_device *pdev) |
ce792580 TC |
206 | { |
207 | struct tiny_spi *hw = platform_get_drvdata(pdev); | |
208 | struct device_node *np = pdev->dev.of_node; | |
209 | unsigned int i; | |
210 | const __be32 *val; | |
211 | int len; | |
212 | ||
213 | if (!np) | |
214 | return 0; | |
215 | hw->gpio_cs_count = of_gpio_count(np); | |
e80beb27 | 216 | if (hw->gpio_cs_count > 0) { |
ce792580 TC |
217 | hw->gpio_cs = devm_kzalloc(&pdev->dev, |
218 | hw->gpio_cs_count * sizeof(unsigned int), | |
219 | GFP_KERNEL); | |
220 | if (!hw->gpio_cs) | |
221 | return -ENOMEM; | |
222 | } | |
223 | for (i = 0; i < hw->gpio_cs_count; i++) { | |
224 | hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL); | |
225 | if (hw->gpio_cs[i] < 0) | |
226 | return -ENODEV; | |
227 | } | |
228 | hw->bitbang.master->dev.of_node = pdev->dev.of_node; | |
229 | val = of_get_property(pdev->dev.of_node, | |
230 | "clock-frequency", &len); | |
231 | if (val && len >= sizeof(__be32)) | |
232 | hw->freq = be32_to_cpup(val); | |
233 | val = of_get_property(pdev->dev.of_node, "baud-width", &len); | |
234 | if (val && len >= sizeof(__be32)) | |
235 | hw->baudwidth = be32_to_cpup(val); | |
236 | return 0; | |
237 | } | |
238 | #else /* !CONFIG_OF */ | |
fd4a319b | 239 | static int tiny_spi_of_probe(struct platform_device *pdev) |
ce792580 TC |
240 | { |
241 | return 0; | |
242 | } | |
243 | #endif /* CONFIG_OF */ | |
244 | ||
fd4a319b | 245 | static int tiny_spi_probe(struct platform_device *pdev) |
ce792580 | 246 | { |
8074cf06 | 247 | struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev); |
ce792580 TC |
248 | struct tiny_spi *hw; |
249 | struct spi_master *master; | |
250 | struct resource *res; | |
251 | unsigned int i; | |
252 | int err = -ENODEV; | |
253 | ||
254 | master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi)); | |
255 | if (!master) | |
256 | return err; | |
257 | ||
258 | /* setup the master state. */ | |
259 | master->bus_num = pdev->id; | |
260 | master->num_chipselect = 255; | |
261 | master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; | |
262 | master->setup = tiny_spi_setup; | |
263 | ||
264 | hw = spi_master_get_devdata(master); | |
265 | platform_set_drvdata(pdev, hw); | |
266 | ||
267 | /* setup the state for the bitbang driver */ | |
94c69f76 | 268 | hw->bitbang.master = master; |
ce792580 TC |
269 | hw->bitbang.setup_transfer = tiny_spi_setup_transfer; |
270 | hw->bitbang.chipselect = tiny_spi_chipselect; | |
271 | hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs; | |
272 | ||
273 | /* find and map our resources */ | |
274 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
b3136f8f JL |
275 | hw->base = devm_ioremap_resource(&pdev->dev, res); |
276 | if (IS_ERR(hw->base)) { | |
277 | err = PTR_ERR(hw->base); | |
278 | goto exit; | |
279 | } | |
ce792580 TC |
280 | /* irq is optional */ |
281 | hw->irq = platform_get_irq(pdev, 0); | |
282 | if (hw->irq >= 0) { | |
283 | init_completion(&hw->done); | |
284 | err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0, | |
285 | pdev->name, hw); | |
286 | if (err) | |
287 | goto exit; | |
288 | } | |
289 | /* find platform data */ | |
290 | if (platp) { | |
291 | hw->gpio_cs_count = platp->gpio_cs_count; | |
292 | hw->gpio_cs = platp->gpio_cs; | |
b3136f8f JL |
293 | if (platp->gpio_cs_count && !platp->gpio_cs) { |
294 | err = -EBUSY; | |
295 | goto exit; | |
296 | } | |
ce792580 TC |
297 | hw->freq = platp->freq; |
298 | hw->baudwidth = platp->baudwidth; | |
299 | } else { | |
300 | err = tiny_spi_of_probe(pdev); | |
301 | if (err) | |
302 | goto exit; | |
303 | } | |
304 | for (i = 0; i < hw->gpio_cs_count; i++) { | |
305 | err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev)); | |
306 | if (err) | |
307 | goto exit_gpio; | |
308 | gpio_direction_output(hw->gpio_cs[i], 1); | |
309 | } | |
e80beb27 | 310 | hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count); |
ce792580 TC |
311 | |
312 | /* register our spi controller */ | |
313 | err = spi_bitbang_start(&hw->bitbang); | |
314 | if (err) | |
315 | goto exit; | |
316 | dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); | |
317 | ||
318 | return 0; | |
319 | ||
320 | exit_gpio: | |
321 | while (i-- > 0) | |
322 | gpio_free(hw->gpio_cs[i]); | |
ce792580 | 323 | exit: |
ce792580 TC |
324 | spi_master_put(master); |
325 | return err; | |
326 | } | |
327 | ||
fd4a319b | 328 | static int tiny_spi_remove(struct platform_device *pdev) |
ce792580 TC |
329 | { |
330 | struct tiny_spi *hw = platform_get_drvdata(pdev); | |
331 | struct spi_master *master = hw->bitbang.master; | |
332 | unsigned int i; | |
333 | ||
334 | spi_bitbang_stop(&hw->bitbang); | |
335 | for (i = 0; i < hw->gpio_cs_count; i++) | |
336 | gpio_free(hw->gpio_cs[i]); | |
ce792580 TC |
337 | spi_master_put(master); |
338 | return 0; | |
339 | } | |
340 | ||
341 | #ifdef CONFIG_OF | |
342 | static const struct of_device_id tiny_spi_match[] = { | |
343 | { .compatible = "opencores,tiny-spi-rtlsvn2", }, | |
344 | {}, | |
345 | }; | |
346 | MODULE_DEVICE_TABLE(of, tiny_spi_match); | |
ce792580 TC |
347 | #endif /* CONFIG_OF */ |
348 | ||
349 | static struct platform_driver tiny_spi_driver = { | |
350 | .probe = tiny_spi_probe, | |
fd4a319b | 351 | .remove = tiny_spi_remove, |
ce792580 TC |
352 | .driver = { |
353 | .name = DRV_NAME, | |
354 | .owner = THIS_MODULE, | |
355 | .pm = NULL, | |
9547acce | 356 | .of_match_table = of_match_ptr(tiny_spi_match), |
ce792580 TC |
357 | }, |
358 | }; | |
940ab889 | 359 | module_platform_driver(tiny_spi_driver); |
ce792580 TC |
360 | |
361 | MODULE_DESCRIPTION("OpenCores tiny SPI driver"); | |
362 | MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); | |
363 | MODULE_LICENSE("GPL"); | |
364 | MODULE_ALIAS("platform:" DRV_NAME); |