1 /*
2 * Copyright (c) 2009 Nuvoton technology.
3 * Wan ZongShun <mcuos.com@gmail.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 */
10
11 #include <linux/module.h>
12 #include <linux/spinlock.h>
13 #include <linux/interrupt.h>
14 #include <linux/delay.h>
15 #include <linux/errno.h>
16 #include <linux/err.h>
17 #include <linux/clk.h>
18 #include <linux/device.h>
19 #include <linux/platform_device.h>
20 #include <linux/gpio.h>
21 #include <linux/io.h>
22 #include <linux/slab.h>
23
24 #include <linux/spi/spi.h>
25 #include <linux/spi/spi_bitbang.h>
26
27 #include <linux/platform_data/spi-nuc900.h>
28
29 /* usi registers offset */
30 #define USI_CNT 0x00
31 #define USI_DIV 0x04
32 #define USI_SSR 0x08
33 #define USI_RX0 0x10
34 #define USI_TX0 0x10
35
36 /* usi register bit */
37 #define ENINT (0x01 << 17)
38 #define ENFLG (0x01 << 16)
39 #define SLEEP (0x0f << 12)
40 #define TXNUM (0x03 << 8)
41 #define TXBITLEN (0x1f << 3)
42 #define TXNEG (0x01 << 2)
43 #define RXNEG (0x01 << 1)
44 #define LSB (0x01 << 10)
45 #define SELECTLEV (0x01 << 2)
46 #define SELECTPOL (0x01 << 31)
47 #define SELECTSLAVE 0x01
48 #define GOBUSY 0x01
49
50 struct nuc900_spi {
51 struct spi_bitbang bitbang;
52 struct completion done;
53 void __iomem *regs;
54 int irq;
55 int len;
56 int count;
57 const unsigned char *tx;
58 unsigned char *rx;
59 struct clk *clk;
60 struct spi_master *master;
61 struct nuc900_spi_info *pdata;
62 spinlock_t lock;
63 };
64
to_hw(struct spi_device * sdev)65 static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
66 {
67 return spi_master_get_devdata(sdev->master);
68 }
69
nuc900_slave_select(struct spi_device * spi,unsigned int ssr)70 static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
71 {
72 struct nuc900_spi *hw = to_hw(spi);
73 unsigned int val;
74 unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
75 unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
76 unsigned long flags;
77
78 spin_lock_irqsave(&hw->lock, flags);
79
80 val = __raw_readl(hw->regs + USI_SSR);
81
82 if (!cs)
83 val &= ~SELECTLEV;
84 else
85 val |= SELECTLEV;
86
87 if (!ssr)
88 val &= ~SELECTSLAVE;
89 else
90 val |= SELECTSLAVE;
91
92 __raw_writel(val, hw->regs + USI_SSR);
93
94 val = __raw_readl(hw->regs + USI_CNT);
95
96 if (!cpol)
97 val &= ~SELECTPOL;
98 else
99 val |= SELECTPOL;
100
101 __raw_writel(val, hw->regs + USI_CNT);
102
103 spin_unlock_irqrestore(&hw->lock, flags);
104 }
105
nuc900_spi_chipsel(struct spi_device * spi,int value)106 static void nuc900_spi_chipsel(struct spi_device *spi, int value)
107 {
108 switch (value) {
109 case BITBANG_CS_INACTIVE:
110 nuc900_slave_select(spi, 0);
111 break;
112
113 case BITBANG_CS_ACTIVE:
114 nuc900_slave_select(spi, 1);
115 break;
116 }
117 }
118
nuc900_spi_setup_txnum(struct nuc900_spi * hw,unsigned int txnum)119 static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
120 {
121 unsigned int val;
122 unsigned long flags;
123
124 spin_lock_irqsave(&hw->lock, flags);
125
126 val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;
127
128 if (txnum)
129 val |= txnum << 0x08;
130
131 __raw_writel(val, hw->regs + USI_CNT);
132
133 spin_unlock_irqrestore(&hw->lock, flags);
134
135 }
136
nuc900_spi_setup_txbitlen(struct nuc900_spi * hw,unsigned int txbitlen)137 static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
138 unsigned int txbitlen)
139 {
140 unsigned int val;
141 unsigned long flags;
142
143 spin_lock_irqsave(&hw->lock, flags);
144
145 val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;
146
147 val |= (txbitlen << 0x03);
148
149 __raw_writel(val, hw->regs + USI_CNT);
150
151 spin_unlock_irqrestore(&hw->lock, flags);
152 }
153
nuc900_spi_gobusy(struct nuc900_spi * hw)154 static void nuc900_spi_gobusy(struct nuc900_spi *hw)
155 {
156 unsigned int val;
157 unsigned long flags;
158
159 spin_lock_irqsave(&hw->lock, flags);
160
161 val = __raw_readl(hw->regs + USI_CNT);
162
163 val |= GOBUSY;
164
165 __raw_writel(val, hw->regs + USI_CNT);
166
167 spin_unlock_irqrestore(&hw->lock, flags);
168 }
169
hw_txbyte(struct nuc900_spi * hw,int count)170 static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
171 {
172 return hw->tx ? hw->tx[count] : 0;
173 }
174
nuc900_spi_txrx(struct spi_device * spi,struct spi_transfer * t)175 static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
176 {
177 struct nuc900_spi *hw = to_hw(spi);
178
179 hw->tx = t->tx_buf;
180 hw->rx = t->rx_buf;
181 hw->len = t->len;
182 hw->count = 0;
183
184 __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
185
186 nuc900_spi_gobusy(hw);
187
188 wait_for_completion(&hw->done);
189
190 return hw->count;
191 }
192
nuc900_spi_irq(int irq,void * dev)193 static irqreturn_t nuc900_spi_irq(int irq, void *dev)
194 {
195 struct nuc900_spi *hw = dev;
196 unsigned int status;
197 unsigned int count = hw->count;
198
199 status = __raw_readl(hw->regs + USI_CNT);
200 __raw_writel(status, hw->regs + USI_CNT);
201
202 if (status & ENFLG) {
203 hw->count++;
204
205 if (hw->rx)
206 hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
207 count++;
208
209 if (count < hw->len) {
210 __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
211 nuc900_spi_gobusy(hw);
212 } else {
213 complete(&hw->done);
214 }
215
216 return IRQ_HANDLED;
217 }
218
219 complete(&hw->done);
220 return IRQ_HANDLED;
221 }
222
nuc900_tx_edge(struct nuc900_spi * hw,unsigned int edge)223 static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
224 {
225 unsigned int val;
226 unsigned long flags;
227
228 spin_lock_irqsave(&hw->lock, flags);
229
230 val = __raw_readl(hw->regs + USI_CNT);
231
232 if (edge)
233 val |= TXNEG;
234 else
235 val &= ~TXNEG;
236 __raw_writel(val, hw->regs + USI_CNT);
237
238 spin_unlock_irqrestore(&hw->lock, flags);
239 }
240
nuc900_rx_edge(struct nuc900_spi * hw,unsigned int edge)241 static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
242 {
243 unsigned int val;
244 unsigned long flags;
245
246 spin_lock_irqsave(&hw->lock, flags);
247
248 val = __raw_readl(hw->regs + USI_CNT);
249
250 if (edge)
251 val |= RXNEG;
252 else
253 val &= ~RXNEG;
254 __raw_writel(val, hw->regs + USI_CNT);
255
256 spin_unlock_irqrestore(&hw->lock, flags);
257 }
258
nuc900_send_first(struct nuc900_spi * hw,unsigned int lsb)259 static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
260 {
261 unsigned int val;
262 unsigned long flags;
263
264 spin_lock_irqsave(&hw->lock, flags);
265
266 val = __raw_readl(hw->regs + USI_CNT);
267
268 if (lsb)
269 val |= LSB;
270 else
271 val &= ~LSB;
272 __raw_writel(val, hw->regs + USI_CNT);
273
274 spin_unlock_irqrestore(&hw->lock, flags);
275 }
276
nuc900_set_sleep(struct nuc900_spi * hw,unsigned int sleep)277 static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
278 {
279 unsigned int val;
280 unsigned long flags;
281
282 spin_lock_irqsave(&hw->lock, flags);
283
284 val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;
285
286 if (sleep)
287 val |= (sleep << 12);
288
289 __raw_writel(val, hw->regs + USI_CNT);
290
291 spin_unlock_irqrestore(&hw->lock, flags);
292 }
293
nuc900_enable_int(struct nuc900_spi * hw)294 static void nuc900_enable_int(struct nuc900_spi *hw)
295 {
296 unsigned int val;
297 unsigned long flags;
298
299 spin_lock_irqsave(&hw->lock, flags);
300
301 val = __raw_readl(hw->regs + USI_CNT);
302
303 val |= ENINT;
304
305 __raw_writel(val, hw->regs + USI_CNT);
306
307 spin_unlock_irqrestore(&hw->lock, flags);
308 }
309
nuc900_set_divider(struct nuc900_spi * hw)310 static void nuc900_set_divider(struct nuc900_spi *hw)
311 {
312 __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
313 }
314
nuc900_init_spi(struct nuc900_spi * hw)315 static void nuc900_init_spi(struct nuc900_spi *hw)
316 {
317 clk_enable(hw->clk);
318 spin_lock_init(&hw->lock);
319
320 nuc900_tx_edge(hw, hw->pdata->txneg);
321 nuc900_rx_edge(hw, hw->pdata->rxneg);
322 nuc900_send_first(hw, hw->pdata->lsb);
323 nuc900_set_sleep(hw, hw->pdata->sleep);
324 nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
325 nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
326 nuc900_set_divider(hw);
327 nuc900_enable_int(hw);
328 }
329
nuc900_spi_probe(struct platform_device * pdev)330 static int nuc900_spi_probe(struct platform_device *pdev)
331 {
332 struct nuc900_spi *hw;
333 struct spi_master *master;
334 struct resource *res;
335 int err = 0;
336
337 master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
338 if (master == NULL) {
339 dev_err(&pdev->dev, "No memory for spi_master\n");
340 return -ENOMEM;
341 }
342
343 hw = spi_master_get_devdata(master);
344 hw->master = master;
345 hw->pdata = dev_get_platdata(&pdev->dev);
346
347 if (hw->pdata == NULL) {
348 dev_err(&pdev->dev, "No platform data supplied\n");
349 err = -ENOENT;
350 goto err_pdata;
351 }
352
353 platform_set_drvdata(pdev, hw);
354 init_completion(&hw->done);
355
356 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
357 if (hw->pdata->lsb)
358 master->mode_bits |= SPI_LSB_FIRST;
359 master->num_chipselect = hw->pdata->num_cs;
360 master->bus_num = hw->pdata->bus_num;
361 hw->bitbang.master = hw->master;
362 hw->bitbang.chipselect = nuc900_spi_chipsel;
363 hw->bitbang.txrx_bufs = nuc900_spi_txrx;
364
365 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
366 hw->regs = devm_ioremap_resource(&pdev->dev, res);
367 if (IS_ERR(hw->regs)) {
368 err = PTR_ERR(hw->regs);
369 goto err_pdata;
370 }
371
372 hw->irq = platform_get_irq(pdev, 0);
373 if (hw->irq < 0) {
374 dev_err(&pdev->dev, "No IRQ specified\n");
375 err = -ENOENT;
376 goto err_pdata;
377 }
378
379 err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
380 pdev->name, hw);
381 if (err) {
382 dev_err(&pdev->dev, "Cannot claim IRQ\n");
383 goto err_pdata;
384 }
385
386 hw->clk = devm_clk_get(&pdev->dev, "spi");
387 if (IS_ERR(hw->clk)) {
388 dev_err(&pdev->dev, "No clock for device\n");
389 err = PTR_ERR(hw->clk);
390 goto err_pdata;
391 }
392
393 mfp_set_groupg(&pdev->dev, NULL);
394 nuc900_init_spi(hw);
395
396 err = spi_bitbang_start(&hw->bitbang);
397 if (err) {
398 dev_err(&pdev->dev, "Failed to register SPI master\n");
399 goto err_register;
400 }
401
402 return 0;
403
404 err_register:
405 clk_disable(hw->clk);
406 err_pdata:
407 spi_master_put(hw->master);
408 return err;
409 }
410
nuc900_spi_remove(struct platform_device * dev)411 static int nuc900_spi_remove(struct platform_device *dev)
412 {
413 struct nuc900_spi *hw = platform_get_drvdata(dev);
414
415 spi_bitbang_stop(&hw->bitbang);
416 clk_disable(hw->clk);
417 spi_master_put(hw->master);
418 return 0;
419 }
420
421 static struct platform_driver nuc900_spi_driver = {
422 .probe = nuc900_spi_probe,
423 .remove = nuc900_spi_remove,
424 .driver = {
425 .name = "nuc900-spi",
426 },
427 };
428 module_platform_driver(nuc900_spi_driver);
429
430 MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
431 MODULE_DESCRIPTION("nuc900 spi driver!");
432 MODULE_LICENSE("GPL");
433 MODULE_ALIAS("platform:nuc900-spi");
434
