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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/spinlock.h>
Wan ZongShun30eaed02009-12-01 14:29:20 +000013#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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090022#include <linux/slab.h>
Wan ZongShun30eaed02009-12-01 14:29:20 +000023
24#include <linux/spi/spi.h>
25#include <linux/spi/spi_bitbang.h>
26
Arnd Bergmann54ecf4f2012-08-24 15:18:36 +020027#include <linux/platform_data/spi-nuc900.h>
Wan ZongShun30eaed02009-12-01 14:29:20 +000028
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)
Axel Linfb534f12014-03-21 13:24:14 +080039#define SLEEP (0x0f << 12)
Wan ZongShun30eaed02009-12-01 14:29:20 +000040#define TXNUM (0x03 << 8)
Axel Linfb534f12014-03-21 13:24:14 +080041#define TXBITLEN (0x1f << 3)
Wan ZongShun30eaed02009-12-01 14:29:20 +000042#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;
Wan ZongShun30eaed02009-12-01 14:29:20 +000061 struct nuc900_spi_info *pdata;
62 spinlock_t lock;
Wan ZongShun30eaed02009-12-01 14:29:20 +000063};
64
65static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
66{
67 return spi_master_get_devdata(sdev->master);
68}
69
70static 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
106static 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
Axel Linfb534f12014-03-21 13:24:14 +0800119static void nuc900_spi_setup_txnum(struct nuc900_spi *hw, unsigned int txnum)
Wan ZongShun30eaed02009-12-01 14:29:20 +0000120{
121 unsigned int val;
122 unsigned long flags;
123
124 spin_lock_irqsave(&hw->lock, flags);
125
Axel Linfb534f12014-03-21 13:24:14 +0800126 val = __raw_readl(hw->regs + USI_CNT) & ~TXNUM;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000127
Axel Linfb534f12014-03-21 13:24:14 +0800128 if (txnum)
Wan ZongShun30eaed02009-12-01 14:29:20 +0000129 val |= txnum << 0x08;
130
131 __raw_writel(val, hw->regs + USI_CNT);
132
133 spin_unlock_irqrestore(&hw->lock, flags);
134
135}
136
137static 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
Axel Linfb534f12014-03-21 13:24:14 +0800145 val = __raw_readl(hw->regs + USI_CNT) & ~TXBITLEN;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000146
147 val |= (txbitlen << 0x03);
148
149 __raw_writel(val, hw->regs + USI_CNT);
150
151 spin_unlock_irqrestore(&hw->lock, flags);
152}
153
154static 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
Wan ZongShun30eaed02009-12-01 14:29:20 +0000170static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
171{
172 return hw->tx ? hw->tx[count] : 0;
173}
174
175static 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
193static 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
223static 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
241static 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
259static 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
277static 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
Axel Linfb534f12014-03-21 13:24:14 +0800284 val = __raw_readl(hw->regs + USI_CNT) & ~SLEEP;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000285
286 if (sleep)
287 val |= (sleep << 12);
Axel Linfb534f12014-03-21 13:24:14 +0800288
Wan ZongShun30eaed02009-12-01 14:29:20 +0000289 __raw_writel(val, hw->regs + USI_CNT);
290
291 spin_unlock_irqrestore(&hw->lock, flags);
292}
293
294static 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
310static void nuc900_set_divider(struct nuc900_spi *hw)
311{
312 __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
313}
314
315static 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
Grant Likelyfd4a3192012-12-07 16:57:14 +0000330static int nuc900_spi_probe(struct platform_device *pdev)
Wan ZongShun30eaed02009-12-01 14:29:20 +0000331{
332 struct nuc900_spi *hw;
333 struct spi_master *master;
Axel Lin8120ff82014-02-08 11:15:57 +0800334 struct resource *res;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000335 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");
Jingoo Han75194592013-12-09 19:18:18 +0900340 return -ENOMEM;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000341 }
342
343 hw = spi_master_get_devdata(master);
Axel Lin94c69f72013-09-10 15:43:41 +0800344 hw->master = master;
Jingoo Han8074cf02013-07-30 16:58:59 +0900345 hw->pdata = dev_get_platdata(&pdev->dev);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000346
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
Axel Lin044d0bb2013-08-15 14:11:21 +0800356 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
Axel Linf7db1582014-01-20 23:22:07 +0800357 if (hw->pdata->lsb)
358 master->mode_bits |= SPI_LSB_FIRST;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000359 master->num_chipselect = hw->pdata->num_cs;
360 master->bus_num = hw->pdata->bus_num;
361 hw->bitbang.master = hw->master;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000362 hw->bitbang.chipselect = nuc900_spi_chipsel;
363 hw->bitbang.txrx_bufs = nuc900_spi_txrx;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000364
Axel Lin8120ff82014-02-08 11:15:57 +0800365 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
366 hw->regs = devm_ioremap_resource(&pdev->dev, res);
Jingoo Han75194592013-12-09 19:18:18 +0900367 if (IS_ERR(hw->regs)) {
368 err = PTR_ERR(hw->regs);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000369 goto err_pdata;
370 }
371
Wan ZongShun30eaed02009-12-01 14:29:20 +0000372 hw->irq = platform_get_irq(pdev, 0);
373 if (hw->irq < 0) {
374 dev_err(&pdev->dev, "No IRQ specified\n");
375 err = -ENOENT;
Jingoo Han75194592013-12-09 19:18:18 +0900376 goto err_pdata;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000377 }
378
Jingoo Han75194592013-12-09 19:18:18 +0900379 err = devm_request_irq(&pdev->dev, hw->irq, nuc900_spi_irq, 0,
380 pdev->name, hw);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000381 if (err) {
382 dev_err(&pdev->dev, "Cannot claim IRQ\n");
Jingoo Han75194592013-12-09 19:18:18 +0900383 goto err_pdata;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000384 }
385
Jingoo Han75194592013-12-09 19:18:18 +0900386 hw->clk = devm_clk_get(&pdev->dev, "spi");
Wan ZongShun30eaed02009-12-01 14:29:20 +0000387 if (IS_ERR(hw->clk)) {
388 dev_err(&pdev->dev, "No clock for device\n");
389 err = PTR_ERR(hw->clk);
Jingoo Han75194592013-12-09 19:18:18 +0900390 goto err_pdata;
Wan ZongShun30eaed02009-12-01 14:29:20 +0000391 }
392
Axel Lin97371fa2011-11-25 00:23:28 +0100393 mfp_set_groupg(&pdev->dev, NULL);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000394 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
404err_register:
405 clk_disable(hw->clk);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000406err_pdata:
Joe Perchesbc3f67a2010-11-14 19:04:47 -0800407 spi_master_put(hw->master);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000408 return err;
409}
410
Grant Likelyfd4a3192012-12-07 16:57:14 +0000411static int nuc900_spi_remove(struct platform_device *dev)
Wan ZongShun30eaed02009-12-01 14:29:20 +0000412{
413 struct nuc900_spi *hw = platform_get_drvdata(dev);
414
Axel Lin708a7e42011-05-15 07:33:28 +0800415 spi_bitbang_stop(&hw->bitbang);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000416 clk_disable(hw->clk);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000417 spi_master_put(hw->master);
418 return 0;
419}
420
421static struct platform_driver nuc900_spi_driver = {
422 .probe = nuc900_spi_probe,
Grant Likelyfd4a3192012-12-07 16:57:14 +0000423 .remove = nuc900_spi_remove,
Wan ZongShun30eaed02009-12-01 14:29:20 +0000424 .driver = {
425 .name = "nuc900-spi",
426 .owner = THIS_MODULE,
427 },
428};
Grant Likely940ab882011-10-05 11:29:49 -0600429module_platform_driver(nuc900_spi_driver);
Wan ZongShun30eaed02009-12-01 14:29:20 +0000430
431MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
432MODULE_DESCRIPTION("nuc900 spi driver!");
433MODULE_LICENSE("GPL");
434MODULE_ALIAS("platform:nuc900-spi");