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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
47struct 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
64static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
65{
66 return spi_master_get_devdata(sdev->master);
67}
68
69static 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
105static int altera_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
106{
107 return 0;
108}
109
110static int altera_spi_setup(struct spi_device *spi)
111{
112 return 0;
113}
114
115static 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
129static 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
189static 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
217static 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
284exit_busy:
285 err = -EBUSY;
286exit:
287 platform_set_drvdata(pdev, NULL);
288 spi_master_put(master);
289 return err;
290}
291
292static 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
304static const struct of_device_id altera_spi_match[] = {
305 { .compatible = "ALTR,spi-1.0", },
306 {},
307};
308MODULE_DEVICE_TABLE(of, altera_spi_match);
309#else /* CONFIG_OF */
310#define altera_spi_match NULL
311#endif /* CONFIG_OF */
312
313static 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
324static int __init altera_spi_init(void)
325{
326 return platform_driver_register(&altera_spi_driver);
327}
328module_init(altera_spi_init);
329
330static void __exit altera_spi_exit(void)
331{
332 platform_driver_unregister(&altera_spi_driver);
333}
334module_exit(altera_spi_exit);
335
336MODULE_DESCRIPTION("Altera SPI driver");
337MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
338MODULE_LICENSE("GPL");
339MODULE_ALIAS("platform:" DRV_NAME);