Commit | Line | Data |
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0b782531 TC |
1 | /* |
2 | * Altera SPI driver | |
3 | * | |
4 | * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw> | |
5 | * | |
6 | * Based on spi_s3c24xx.c, which is: | |
7 | * Copyright (c) 2006 Ben Dooks | |
8 | * Copyright (c) 2006 Simtec Electronics | |
9 | * Ben Dooks <ben@simtec.co.uk> | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License version 2 as | |
13 | * published by the Free Software Foundation. | |
14 | */ | |
15 | ||
16 | #include <linux/init.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/errno.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/spi/spi.h> | |
21 | #include <linux/spi/spi_bitbang.h> | |
22 | #include <linux/io.h> | |
23 | #include <linux/of.h> | |
24 | ||
25 | #define DRV_NAME "spi_altera" | |
26 | ||
27 | #define ALTERA_SPI_RXDATA 0 | |
28 | #define ALTERA_SPI_TXDATA 4 | |
29 | #define ALTERA_SPI_STATUS 8 | |
30 | #define ALTERA_SPI_CONTROL 12 | |
31 | #define ALTERA_SPI_SLAVE_SEL 20 | |
32 | ||
33 | #define ALTERA_SPI_STATUS_ROE_MSK 0x8 | |
34 | #define ALTERA_SPI_STATUS_TOE_MSK 0x10 | |
35 | #define ALTERA_SPI_STATUS_TMT_MSK 0x20 | |
36 | #define ALTERA_SPI_STATUS_TRDY_MSK 0x40 | |
37 | #define ALTERA_SPI_STATUS_RRDY_MSK 0x80 | |
38 | #define ALTERA_SPI_STATUS_E_MSK 0x100 | |
39 | ||
40 | #define ALTERA_SPI_CONTROL_IROE_MSK 0x8 | |
41 | #define ALTERA_SPI_CONTROL_ITOE_MSK 0x10 | |
42 | #define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40 | |
43 | #define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80 | |
44 | #define ALTERA_SPI_CONTROL_IE_MSK 0x100 | |
45 | #define ALTERA_SPI_CONTROL_SSO_MSK 0x400 | |
46 | ||
47 | struct altera_spi { | |
48 | /* bitbang has to be first */ | |
49 | struct spi_bitbang bitbang; | |
50 | struct completion done; | |
51 | ||
52 | void __iomem *base; | |
53 | int irq; | |
54 | int len; | |
55 | int count; | |
56 | int bytes_per_word; | |
57 | unsigned long imr; | |
58 | ||
59 | /* data buffers */ | |
60 | const unsigned char *tx; | |
61 | unsigned char *rx; | |
62 | }; | |
63 | ||
64 | static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev) | |
65 | { | |
66 | return spi_master_get_devdata(sdev->master); | |
67 | } | |
68 | ||
69 | static void altera_spi_chipsel(struct spi_device *spi, int value) | |
70 | { | |
71 | struct altera_spi *hw = altera_spi_to_hw(spi); | |
72 | ||
73 | if (spi->mode & SPI_CS_HIGH) { | |
74 | switch (value) { | |
75 | case BITBANG_CS_INACTIVE: | |
76 | writel(1 << spi->chip_select, | |
77 | hw->base + ALTERA_SPI_SLAVE_SEL); | |
78 | hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; | |
79 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
80 | break; | |
81 | ||
82 | case BITBANG_CS_ACTIVE: | |
83 | hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK; | |
84 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
85 | writel(0, hw->base + ALTERA_SPI_SLAVE_SEL); | |
86 | break; | |
87 | } | |
88 | } else { | |
89 | switch (value) { | |
90 | case BITBANG_CS_INACTIVE: | |
91 | hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK; | |
92 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
93 | break; | |
94 | ||
95 | case BITBANG_CS_ACTIVE: | |
96 | writel(1 << spi->chip_select, | |
97 | hw->base + ALTERA_SPI_SLAVE_SEL); | |
98 | hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; | |
99 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
100 | break; | |
101 | } | |
102 | } | |
103 | } | |
104 | ||
105 | static int altera_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t) | |
106 | { | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static int altera_spi_setup(struct spi_device *spi) | |
111 | { | |
112 | return 0; | |
113 | } | |
114 | ||
115 | static inline unsigned int hw_txbyte(struct altera_spi *hw, int count) | |
116 | { | |
117 | if (hw->tx) { | |
118 | switch (hw->bytes_per_word) { | |
119 | case 1: | |
120 | return hw->tx[count]; | |
121 | case 2: | |
122 | return (hw->tx[count * 2] | |
123 | | (hw->tx[count * 2 + 1] << 8)); | |
124 | } | |
125 | } | |
126 | return 0; | |
127 | } | |
128 | ||
129 | static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t) | |
130 | { | |
131 | struct altera_spi *hw = altera_spi_to_hw(spi); | |
132 | ||
133 | hw->tx = t->tx_buf; | |
134 | hw->rx = t->rx_buf; | |
135 | hw->count = 0; | |
136 | hw->bytes_per_word = (t->bits_per_word ? : spi->bits_per_word) / 8; | |
137 | hw->len = t->len / hw->bytes_per_word; | |
138 | ||
139 | if (hw->irq >= 0) { | |
140 | /* enable receive interrupt */ | |
141 | hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK; | |
142 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
143 | ||
144 | /* send the first byte */ | |
145 | writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA); | |
146 | ||
147 | wait_for_completion(&hw->done); | |
148 | /* disable receive interrupt */ | |
149 | hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK; | |
150 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
151 | } else { | |
152 | /* send the first byte */ | |
153 | writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA); | |
154 | ||
155 | while (1) { | |
156 | unsigned int rxd; | |
157 | ||
158 | while (!(readl(hw->base + ALTERA_SPI_STATUS) & | |
159 | ALTERA_SPI_STATUS_RRDY_MSK)) | |
160 | cpu_relax(); | |
161 | ||
162 | rxd = readl(hw->base + ALTERA_SPI_RXDATA); | |
163 | if (hw->rx) { | |
164 | switch (hw->bytes_per_word) { | |
165 | case 1: | |
166 | hw->rx[hw->count] = rxd; | |
167 | break; | |
168 | case 2: | |
169 | hw->rx[hw->count * 2] = rxd; | |
170 | hw->rx[hw->count * 2 + 1] = rxd >> 8; | |
171 | break; | |
172 | } | |
173 | } | |
174 | ||
175 | hw->count++; | |
176 | ||
177 | if (hw->count < hw->len) | |
178 | writel(hw_txbyte(hw, hw->count), | |
179 | hw->base + ALTERA_SPI_TXDATA); | |
180 | else | |
181 | break; | |
182 | } | |
183 | ||
184 | } | |
185 | ||
186 | return hw->count * hw->bytes_per_word; | |
187 | } | |
188 | ||
189 | static irqreturn_t altera_spi_irq(int irq, void *dev) | |
190 | { | |
191 | struct altera_spi *hw = dev; | |
192 | unsigned int rxd; | |
193 | ||
194 | rxd = readl(hw->base + ALTERA_SPI_RXDATA); | |
195 | if (hw->rx) { | |
196 | switch (hw->bytes_per_word) { | |
197 | case 1: | |
198 | hw->rx[hw->count] = rxd; | |
199 | break; | |
200 | case 2: | |
201 | hw->rx[hw->count * 2] = rxd; | |
202 | hw->rx[hw->count * 2 + 1] = rxd >> 8; | |
203 | break; | |
204 | } | |
205 | } | |
206 | ||
207 | hw->count++; | |
208 | ||
209 | if (hw->count < hw->len) | |
210 | writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA); | |
211 | else | |
212 | complete(&hw->done); | |
213 | ||
214 | return IRQ_HANDLED; | |
215 | } | |
216 | ||
217 | static int __devinit altera_spi_probe(struct platform_device *pdev) | |
218 | { | |
219 | struct altera_spi_platform_data *platp = pdev->dev.platform_data; | |
220 | struct altera_spi *hw; | |
221 | struct spi_master *master; | |
222 | struct resource *res; | |
223 | int err = -ENODEV; | |
224 | ||
225 | master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi)); | |
226 | if (!master) | |
227 | return err; | |
228 | ||
229 | /* setup the master state. */ | |
230 | master->bus_num = pdev->id; | |
231 | master->num_chipselect = 16; | |
232 | master->mode_bits = SPI_CS_HIGH; | |
233 | master->setup = altera_spi_setup; | |
234 | ||
235 | hw = spi_master_get_devdata(master); | |
236 | platform_set_drvdata(pdev, hw); | |
237 | ||
238 | /* setup the state for the bitbang driver */ | |
239 | hw->bitbang.master = spi_master_get(master); | |
240 | if (!hw->bitbang.master) | |
241 | return err; | |
242 | hw->bitbang.setup_transfer = altera_spi_setupxfer; | |
243 | hw->bitbang.chipselect = altera_spi_chipsel; | |
244 | hw->bitbang.txrx_bufs = altera_spi_txrx; | |
245 | ||
246 | /* find and map our resources */ | |
247 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
248 | if (!res) | |
249 | goto exit_busy; | |
250 | if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res), | |
251 | pdev->name)) | |
252 | goto exit_busy; | |
253 | hw->base = devm_ioremap_nocache(&pdev->dev, res->start, | |
254 | resource_size(res)); | |
255 | if (!hw->base) | |
256 | goto exit_busy; | |
257 | /* program defaults into the registers */ | |
258 | hw->imr = 0; /* disable spi interrupts */ | |
259 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
260 | writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */ | |
261 | if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK) | |
262 | readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */ | |
263 | /* irq is optional */ | |
264 | hw->irq = platform_get_irq(pdev, 0); | |
265 | if (hw->irq >= 0) { | |
266 | init_completion(&hw->done); | |
267 | err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0, | |
268 | pdev->name, hw); | |
269 | if (err) | |
270 | goto exit; | |
271 | } | |
272 | /* find platform data */ | |
273 | if (!platp) | |
274 | hw->bitbang.master->dev.of_node = pdev->dev.of_node; | |
275 | ||
276 | /* register our spi controller */ | |
277 | err = spi_bitbang_start(&hw->bitbang); | |
278 | if (err) | |
279 | goto exit; | |
280 | dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); | |
281 | ||
282 | return 0; | |
283 | ||
284 | exit_busy: | |
285 | err = -EBUSY; | |
286 | exit: | |
287 | platform_set_drvdata(pdev, NULL); | |
288 | spi_master_put(master); | |
289 | return err; | |
290 | } | |
291 | ||
292 | static int __devexit altera_spi_remove(struct platform_device *dev) | |
293 | { | |
294 | struct altera_spi *hw = platform_get_drvdata(dev); | |
295 | struct spi_master *master = hw->bitbang.master; | |
296 | ||
297 | spi_bitbang_stop(&hw->bitbang); | |
298 | platform_set_drvdata(dev, NULL); | |
299 | spi_master_put(master); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | #ifdef CONFIG_OF | |
304 | static const struct of_device_id altera_spi_match[] = { | |
305 | { .compatible = "ALTR,spi-1.0", }, | |
306 | {}, | |
307 | }; | |
308 | MODULE_DEVICE_TABLE(of, altera_spi_match); | |
309 | #else /* CONFIG_OF */ | |
310 | #define altera_spi_match NULL | |
311 | #endif /* CONFIG_OF */ | |
312 | ||
313 | static struct platform_driver altera_spi_driver = { | |
314 | .probe = altera_spi_probe, | |
315 | .remove = __devexit_p(altera_spi_remove), | |
316 | .driver = { | |
317 | .name = DRV_NAME, | |
318 | .owner = THIS_MODULE, | |
319 | .pm = NULL, | |
320 | .of_match_table = altera_spi_match, | |
321 | }, | |
322 | }; | |
323 | ||
324 | static int __init altera_spi_init(void) | |
325 | { | |
326 | return platform_driver_register(&altera_spi_driver); | |
327 | } | |
328 | module_init(altera_spi_init); | |
329 | ||
330 | static void __exit altera_spi_exit(void) | |
331 | { | |
332 | platform_driver_unregister(&altera_spi_driver); | |
333 | } | |
334 | module_exit(altera_spi_exit); | |
335 | ||
336 | MODULE_DESCRIPTION("Altera SPI driver"); | |
337 | MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); | |
338 | MODULE_LICENSE("GPL"); | |
339 | MODULE_ALIAS("platform:" DRV_NAME); |