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