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Grant Likelyca632f52011-06-06 01:16:30 -06001/*
Wan ZongShun30eaed02009-12-01 14:29:20 +00002 * 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 *
Grant Likelyca632f52011-06-06 01:16:30 -06009 */
Wan ZongShun30eaed02009-12-01 14:29:20 +000010
Axel Lin00d29522011-11-24 11:10:51 +080011#include <linux/module.h>
Wan ZongShun30eaed02009-12-01 14:29:20 +000012#include <linux/init.h>
13#include <linux/spinlock.h>
14#include <linux/workqueue.h>
15#include <linux/interrupt.h>
16#include <linux/delay.h>
17#include <linux/errno.h>
18#include <linux/err.h>
19#include <linux/clk.h>
20#include <linux/device.h>
21#include <linux/platform_device.h>
22#include <linux/gpio.h>
23#include <linux/io.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090024#include <linux/slab.h>
Wan ZongShun30eaed02009-12-01 14:29:20 +000025
26#include <linux/spi/spi.h>
27#include <linux/spi/spi_bitbang.h>
28
Arnd Bergmann54ecf4f2012-08-24 15:18:36 +020029#include <linux/platform_data/spi-nuc900.h>
Wan ZongShun30eaed02009-12-01 14:29:20 +000030
31/* usi registers offset */
32#define USI_CNT 0x00
33#define USI_DIV 0x04
34#define USI_SSR 0x08
35#define USI_RX0 0x10
36#define USI_TX0 0x10
37
38/* usi register bit */
39#define ENINT (0x01 << 17)
40#define ENFLG (0x01 << 16)
41#define TXNUM (0x03 << 8)
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
50struct 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;
Wan ZongShun30eaed02009-12-01 14:29:20 +000060 struct spi_master *master;
61 struct spi_device *curdev;
62 struct device *dev;
63 struct nuc900_spi_info *pdata;
64 spinlock_t lock;
65 struct resource *res;
66};
67
68static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
69{
70 return spi_master_get_devdata(sdev->master);
71}
72
73static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
74{
75 struct nuc900_spi *hw = to_hw(spi);
76 unsigned int val;
77 unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
78 unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
79 unsigned long flags;
80
81 spin_lock_irqsave(&hw->lock, flags);
82
83 val = __raw_readl(hw->regs + USI_SSR);
84
85 if (!cs)
86 val &= ~SELECTLEV;
87 else
88 val |= SELECTLEV;
89
90 if (!ssr)
91 val &= ~SELECTSLAVE;
92 else
93 val |= SELECTSLAVE;
94
95 __raw_writel(val, hw->regs + USI_SSR);
96
97 val = __raw_readl(hw->regs + USI_CNT);
98
99 if (!cpol)
100 val &= ~SELECTPOL;
101 else
102 val |= SELECTPOL;
103
104 __raw_writel(val, hw->regs + USI_CNT);
105
106 spin_unlock_irqrestore(&hw->lock, flags);
107}
108
109static void nuc900_spi_chipsel(struct spi_device *spi, int value)
110{
111 switch (value) {
112 case BITBANG_CS_INACTIVE:
113 nuc900_slave_select(spi, 0);
114 break;
115
116 case BITBANG_CS_ACTIVE:
117 nuc900_slave_select(spi, 1);
118 break;
119 }
120}
121
122static void nuc900_spi_setup_txnum(struct nuc900_spi *hw,
123 unsigned int txnum)
124{
125 unsigned int val;
126 unsigned long flags;
127
128 spin_lock_irqsave(&hw->lock, flags);
129
130 val = __raw_readl(hw->regs + USI_CNT);
131
132 if (!txnum)
133 val &= ~TXNUM;
134 else
135 val |= txnum << 0x08;
136
137 __raw_writel(val, hw->regs + USI_CNT);
138
139 spin_unlock_irqrestore(&hw->lock, flags);
140
141}
142
143static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
144 unsigned int txbitlen)
145{
146 unsigned int val;
147 unsigned long flags;
148
149 spin_lock_irqsave(&hw->lock, flags);
150
151 val = __raw_readl(hw->regs + USI_CNT);
152
153 val |= (txbitlen << 0x03);
154
155 __raw_writel(val, hw->regs + USI_CNT);
156
157 spin_unlock_irqrestore(&hw->lock, flags);
158}
159
160static void nuc900_spi_gobusy(struct nuc900_spi *hw)
161{
162 unsigned int val;
163 unsigned long flags;
164
165 spin_lock_irqsave(&hw->lock, flags);
166
167 val = __raw_readl(hw->regs + USI_CNT);
168
169 val |= GOBUSY;
170
171 __raw_writel(val, hw->regs + USI_CNT);
172
173 spin_unlock_irqrestore(&hw->lock, flags);
174}
175
Wan ZongShun30eaed02009-12-01 14:29:20 +0000176static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
177{
178 return hw->tx ? hw->tx[count] : 0;
179}
180
181static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
182{
183 struct nuc900_spi *hw = to_hw(spi);
184
185 hw->tx = t->tx_buf;
186 hw->rx = t->rx_buf;
187 hw->len = t->len;
188 hw->count = 0;
189
190 __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
191
192 nuc900_spi_gobusy(hw);
193
194 wait_for_completion(&hw->done);
195
196 return hw->count;
197}
198
199static irqreturn_t nuc900_spi_irq(int irq, void *dev)
200{
201 struct nuc900_spi *hw = dev;
202 unsigned int status;
203 unsigned int count = hw->count;
204
205 status = __raw_readl(hw->regs + USI_CNT);
206 __raw_writel(status, hw->regs + USI_CNT);
207
208 if (status & ENFLG) {
209 hw->count++;
210
211 if (hw->rx)
212 hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
213 count++;
214
215 if (count < hw->len) {
216 __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
217 nuc900_spi_gobusy(hw);
218 } else {
219 complete(&hw->done);
220 }
221
222 return IRQ_HANDLED;
223 }
224
225 complete(&hw->done);
226 return IRQ_HANDLED;
227}
228
229static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
230{
231 unsigned int val;
232 unsigned long flags;
233
234 spin_lock_irqsave(&hw->lock, flags);
235
236 val = __raw_readl(hw->regs + USI_CNT);
237
238 if (edge)
239 val |= TXNEG;
240 else
241 val &= ~TXNEG;
242 __raw_writel(val, hw->regs + USI_CNT);
243
244 spin_unlock_irqrestore(&hw->lock, flags);
245}
246
247static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
248{
249 unsigned int val;
250 unsigned long flags;
251
252 spin_lock_irqsave(&hw->lock, flags);
253
254 val = __raw_readl(hw->regs + USI_CNT);
255
256 if (edge)
257 val |= RXNEG;
258 else
259 val &= ~RXNEG;
260 __raw_writel(val, hw->regs + USI_CNT);
261
262 spin_unlock_irqrestore(&hw->lock, flags);
263}
264
265static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
266{
267 unsigned int val;
268 unsigned long flags;
269
270 spin_lock_irqsave(&hw->lock, flags);
271
272 val = __raw_readl(hw->regs + USI_CNT);
273
274 if (lsb)
275 val |= LSB;
276 else
277 val &= ~LSB;
278 __raw_writel(val, hw->regs + USI_CNT);
279
280 spin_unlock_irqrestore(&hw->lock, flags);
281}
282
283static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
284{
285 unsigned int val;
286 unsigned long flags;
287
288 spin_lock_irqsave(&hw->lock, flags);
289
290 val = __raw_readl(hw->regs + USI_CNT);
291
292 if (sleep)
293 val |= (sleep << 12);
294 else
295 val &= ~(0x0f << 12);
296 __raw_writel(val, hw->regs + USI_CNT);
297
298 spin_unlock_irqrestore(&hw->lock, flags);
299}
300
301static void nuc900_enable_int(struct nuc900_spi *hw)
302{
303 unsigned int val;
304 unsigned long flags;
305
306 spin_lock_irqsave(&hw->lock, flags);
307
308 val = __raw_readl(hw->regs + USI_CNT);
309
310 val |= ENINT;
311
312 __raw_writel(val, hw->regs + USI_CNT);
313
314 spin_unlock_irqrestore(&hw->lock, flags);
315}
316
317static void nuc900_set_divider(struct nuc900_spi *hw)
318{
319 __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
320}
321
322static void nuc900_init_spi(struct nuc900_spi *hw)
323{
324 clk_enable(hw->clk);
325 spin_lock_init(&hw->lock);
326
327 nuc900_tx_edge(hw, hw->pdata->txneg);
328 nuc900_rx_edge(hw, hw->pdata->rxneg);
329 nuc900_send_first(hw, hw->pdata->lsb);
330 nuc900_set_sleep(hw, hw->pdata->sleep);
331 nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
332 nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
333 nuc900_set_divider(hw);
334 nuc900_enable_int(hw);
335}
336
Grant Likelyfd4a3192012-12-07 16:57:14 +0000337static int nuc900_spi_probe(struct platform_device *pdev)
Wan ZongShun30eaed02009-12-01 14:29:20 +0000338{
339 struct nuc900_spi *hw;
340 struct spi_master *master;
341 int err = 0;
342
343 master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
344 if (master == NULL) {
345 dev_err(&pdev->dev, "No memory for spi_master\n");
Jingoo Han75194592013-12-09 19:18:18 +0900346 return -ENOMEM;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000347 }
348
349 hw = spi_master_get_devdata(master);
Axel Lin94c69f72013-09-10 15:43:41 +0800350 hw->master = master;
Jingoo Han8074cf02013-07-30 16:58:59 +0900351 hw->pdata = dev_get_platdata(&pdev->dev);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000352 hw->dev = &pdev->dev;
353
354 if (hw->pdata == NULL) {
355 dev_err(&pdev->dev, "No platform data supplied\n");
356 err = -ENOENT;
357 goto err_pdata;
358 }
359
360 platform_set_drvdata(pdev, hw);
361 init_completion(&hw->done);
362
Axel Lin044d0bb2013-08-15 14:11:21 +0800363 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000364 master->num_chipselect = hw->pdata->num_cs;
365 master->bus_num = hw->pdata->bus_num;
366 hw->bitbang.master = hw->master;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000367 hw->bitbang.chipselect = nuc900_spi_chipsel;
368 hw->bitbang.txrx_bufs = nuc900_spi_txrx;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000369
370 hw->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Jingoo Han75194592013-12-09 19:18:18 +0900371 hw->regs = devm_ioremap_resource(&pdev->dev, hw->res);
372 if (IS_ERR(hw->regs)) {
373 err = PTR_ERR(hw->regs);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000374 goto err_pdata;
375 }
376
Wan ZongShun30eaed02009-12-01 14:29:20 +0000377 hw->irq = platform_get_irq(pdev, 0);
378 if (hw->irq < 0) {
379 dev_err(&pdev->dev, "No IRQ specified\n");
380 err = -ENOENT;
Jingoo Han75194592013-12-09 19:18:18 +0900381 goto err_pdata;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000382 }
383
Jingoo Han75194592013-12-09 19:18:18 +0900384 err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
385 pdev->name, hw);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000386 if (err) {
387 dev_err(&pdev->dev, "Cannot claim IRQ\n");
Jingoo Han75194592013-12-09 19:18:18 +0900388 goto err_pdata;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000389 }
390
Jingoo Han75194592013-12-09 19:18:18 +0900391 hw->clk = devm_clk_get(&pdev->dev, "spi");
Wan ZongShun30eaed02009-12-01 14:29:20 +0000392 if (IS_ERR(hw->clk)) {
393 dev_err(&pdev->dev, "No clock for device\n");
394 err = PTR_ERR(hw->clk);
Jingoo Han75194592013-12-09 19:18:18 +0900395 goto err_pdata;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000396 }
397
Axel Lin97371fa2011-11-25 00:23:28 +0100398 mfp_set_groupg(&pdev->dev, NULL);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000399 nuc900_init_spi(hw);
400
401 err = spi_bitbang_start(&hw->bitbang);
402 if (err) {
403 dev_err(&pdev->dev, "Failed to register SPI master\n");
404 goto err_register;
405 }
406
407 return 0;
408
409err_register:
410 clk_disable(hw->clk);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000411err_pdata:
Joe Perchesbc3f67a2010-11-14 19:04:47 -0800412 spi_master_put(hw->master);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000413 return err;
414}
415
Grant Likelyfd4a3192012-12-07 16:57:14 +0000416static int nuc900_spi_remove(struct platform_device *dev)
Wan ZongShun30eaed02009-12-01 14:29:20 +0000417{
418 struct nuc900_spi *hw = platform_get_drvdata(dev);
419
Axel Lin708a7e42011-05-15 07:33:28 +0800420 spi_bitbang_stop(&hw->bitbang);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000421 clk_disable(hw->clk);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000422 spi_master_put(hw->master);
423 return 0;
424}
425
426static struct platform_driver nuc900_spi_driver = {
427 .probe = nuc900_spi_probe,
Grant Likelyfd4a3192012-12-07 16:57:14 +0000428 .remove = nuc900_spi_remove,
Wan ZongShun30eaed02009-12-01 14:29:20 +0000429 .driver = {
430 .name = "nuc900-spi",
431 .owner = THIS_MODULE,
432 },
433};
Grant Likely940ab882011-10-05 11:29:49 -0600434module_platform_driver(nuc900_spi_driver);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000435
436MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
437MODULE_DESCRIPTION("nuc900 spi driver!");
438MODULE_LICENSE("GPL");
439MODULE_ALIAS("platform:nuc900-spi");