This source file includes following definitions.
- tiny_spi_to_hw
- tiny_spi_baud
- tiny_spi_chipselect
- tiny_spi_setup_transfer
- tiny_spi_setup
- tiny_spi_wait_txr
- tiny_spi_wait_txe
- tiny_spi_txrx_bufs
- tiny_spi_irq
- tiny_spi_of_probe
- tiny_spi_of_probe
- tiny_spi_probe
- tiny_spi_remove
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15 #include <linux/interrupt.h>
16 #include <linux/errno.h>
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/spi/spi.h>
20 #include <linux/spi/spi_bitbang.h>
21 #include <linux/spi/spi_oc_tiny.h>
22 #include <linux/io.h>
23 #include <linux/gpio.h>
24 #include <linux/of.h>
25
26 #define DRV_NAME "spi_oc_tiny"
27
28 #define TINY_SPI_RXDATA 0
29 #define TINY_SPI_TXDATA 4
30 #define TINY_SPI_STATUS 8
31 #define TINY_SPI_CONTROL 12
32 #define TINY_SPI_BAUD 16
33
34 #define TINY_SPI_STATUS_TXE 0x1
35 #define TINY_SPI_STATUS_TXR 0x2
36
37 struct tiny_spi {
38
39 struct spi_bitbang bitbang;
40 struct completion done;
41
42 void __iomem *base;
43 int irq;
44 unsigned int freq;
45 unsigned int baudwidth;
46 unsigned int baud;
47 unsigned int speed_hz;
48 unsigned int mode;
49 unsigned int len;
50 unsigned int txc, rxc;
51 const u8 *txp;
52 u8 *rxp;
53 int gpio_cs_count;
54 int *gpio_cs;
55 };
56
57 static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
58 {
59 return spi_master_get_devdata(sdev->master);
60 }
61
62 static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
63 {
64 struct tiny_spi *hw = tiny_spi_to_hw(spi);
65
66 return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
67 }
68
69 static void tiny_spi_chipselect(struct spi_device *spi, int is_active)
70 {
71 struct tiny_spi *hw = tiny_spi_to_hw(spi);
72
73 if (hw->gpio_cs_count > 0) {
74 gpio_set_value(hw->gpio_cs[spi->chip_select],
75 (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
76 }
77 }
78
79 static int tiny_spi_setup_transfer(struct spi_device *spi,
80 struct spi_transfer *t)
81 {
82 struct tiny_spi *hw = tiny_spi_to_hw(spi);
83 unsigned int baud = hw->baud;
84
85 if (t) {
86 if (t->speed_hz && t->speed_hz != hw->speed_hz)
87 baud = tiny_spi_baud(spi, t->speed_hz);
88 }
89 writel(baud, hw->base + TINY_SPI_BAUD);
90 writel(hw->mode, hw->base + TINY_SPI_CONTROL);
91 return 0;
92 }
93
94 static int tiny_spi_setup(struct spi_device *spi)
95 {
96 struct tiny_spi *hw = tiny_spi_to_hw(spi);
97
98 if (spi->max_speed_hz != hw->speed_hz) {
99 hw->speed_hz = spi->max_speed_hz;
100 hw->baud = tiny_spi_baud(spi, hw->speed_hz);
101 }
102 hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA);
103 return 0;
104 }
105
106 static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
107 {
108 while (!(readb(hw->base + TINY_SPI_STATUS) &
109 TINY_SPI_STATUS_TXR))
110 cpu_relax();
111 }
112
113 static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
114 {
115 while (!(readb(hw->base + TINY_SPI_STATUS) &
116 TINY_SPI_STATUS_TXE))
117 cpu_relax();
118 }
119
120 static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
121 {
122 struct tiny_spi *hw = tiny_spi_to_hw(spi);
123 const u8 *txp = t->tx_buf;
124 u8 *rxp = t->rx_buf;
125 unsigned int i;
126
127 if (hw->irq >= 0) {
128
129 hw->len = t->len;
130 hw->txp = t->tx_buf;
131 hw->rxp = t->rx_buf;
132 hw->txc = 0;
133 hw->rxc = 0;
134
135
136 if (t->len > 1) {
137 writeb(hw->txp ? *hw->txp++ : 0,
138 hw->base + TINY_SPI_TXDATA);
139 hw->txc++;
140 writeb(hw->txp ? *hw->txp++ : 0,
141 hw->base + TINY_SPI_TXDATA);
142 hw->txc++;
143 writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
144 } else {
145 writeb(hw->txp ? *hw->txp++ : 0,
146 hw->base + TINY_SPI_TXDATA);
147 hw->txc++;
148 writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
149 }
150
151 wait_for_completion(&hw->done);
152 } else {
153
154 writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
155 for (i = 1; i < t->len; i++) {
156 writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
157
158 if (rxp || (i != t->len - 1))
159 tiny_spi_wait_txr(hw);
160 if (rxp)
161 *rxp++ = readb(hw->base + TINY_SPI_TXDATA);
162 }
163 tiny_spi_wait_txe(hw);
164 if (rxp)
165 *rxp++ = readb(hw->base + TINY_SPI_RXDATA);
166 }
167
168 return t->len;
169 }
170
171 static irqreturn_t tiny_spi_irq(int irq, void *dev)
172 {
173 struct tiny_spi *hw = dev;
174
175 writeb(0, hw->base + TINY_SPI_STATUS);
176 if (hw->rxc + 1 == hw->len) {
177 if (hw->rxp)
178 *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
179 hw->rxc++;
180 complete(&hw->done);
181 } else {
182 if (hw->rxp)
183 *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
184 hw->rxc++;
185 if (hw->txc < hw->len) {
186 writeb(hw->txp ? *hw->txp++ : 0,
187 hw->base + TINY_SPI_TXDATA);
188 hw->txc++;
189 writeb(TINY_SPI_STATUS_TXR,
190 hw->base + TINY_SPI_STATUS);
191 } else {
192 writeb(TINY_SPI_STATUS_TXE,
193 hw->base + TINY_SPI_STATUS);
194 }
195 }
196 return IRQ_HANDLED;
197 }
198
199 #ifdef CONFIG_OF
200 #include <linux/of_gpio.h>
201
202 static int tiny_spi_of_probe(struct platform_device *pdev)
203 {
204 struct tiny_spi *hw = platform_get_drvdata(pdev);
205 struct device_node *np = pdev->dev.of_node;
206 unsigned int i;
207 u32 val;
208
209 if (!np)
210 return 0;
211 hw->gpio_cs_count = of_gpio_count(np);
212 if (hw->gpio_cs_count > 0) {
213 hw->gpio_cs = devm_kcalloc(&pdev->dev,
214 hw->gpio_cs_count, sizeof(unsigned int),
215 GFP_KERNEL);
216 if (!hw->gpio_cs)
217 return -ENOMEM;
218 }
219 for (i = 0; i < hw->gpio_cs_count; i++) {
220 hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL);
221 if (hw->gpio_cs[i] < 0)
222 return -ENODEV;
223 }
224 hw->bitbang.master->dev.of_node = pdev->dev.of_node;
225 if (!of_property_read_u32(np, "clock-frequency", &val))
226 hw->freq = val;
227 if (!of_property_read_u32(np, "baud-width", &val))
228 hw->baudwidth = val;
229 return 0;
230 }
231 #else
232 static int tiny_spi_of_probe(struct platform_device *pdev)
233 {
234 return 0;
235 }
236 #endif
237
238 static int tiny_spi_probe(struct platform_device *pdev)
239 {
240 struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
241 struct tiny_spi *hw;
242 struct spi_master *master;
243 unsigned int i;
244 int err = -ENODEV;
245
246 master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi));
247 if (!master)
248 return err;
249
250
251 master->bus_num = pdev->id;
252 master->num_chipselect = 255;
253 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
254 master->setup = tiny_spi_setup;
255
256 hw = spi_master_get_devdata(master);
257 platform_set_drvdata(pdev, hw);
258
259
260 hw->bitbang.master = master;
261 hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
262 hw->bitbang.chipselect = tiny_spi_chipselect;
263 hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
264
265
266 hw->base = devm_platform_ioremap_resource(pdev, 0);
267 if (IS_ERR(hw->base)) {
268 err = PTR_ERR(hw->base);
269 goto exit;
270 }
271
272 hw->irq = platform_get_irq(pdev, 0);
273 if (hw->irq >= 0) {
274 init_completion(&hw->done);
275 err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
276 pdev->name, hw);
277 if (err)
278 goto exit;
279 }
280
281 if (platp) {
282 hw->gpio_cs_count = platp->gpio_cs_count;
283 hw->gpio_cs = platp->gpio_cs;
284 if (platp->gpio_cs_count && !platp->gpio_cs) {
285 err = -EBUSY;
286 goto exit;
287 }
288 hw->freq = platp->freq;
289 hw->baudwidth = platp->baudwidth;
290 } else {
291 err = tiny_spi_of_probe(pdev);
292 if (err)
293 goto exit;
294 }
295 for (i = 0; i < hw->gpio_cs_count; i++) {
296 err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev));
297 if (err)
298 goto exit_gpio;
299 gpio_direction_output(hw->gpio_cs[i], 1);
300 }
301 hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count);
302
303
304 err = spi_bitbang_start(&hw->bitbang);
305 if (err)
306 goto exit;
307 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
308
309 return 0;
310
311 exit_gpio:
312 while (i-- > 0)
313 gpio_free(hw->gpio_cs[i]);
314 exit:
315 spi_master_put(master);
316 return err;
317 }
318
319 static int tiny_spi_remove(struct platform_device *pdev)
320 {
321 struct tiny_spi *hw = platform_get_drvdata(pdev);
322 struct spi_master *master = hw->bitbang.master;
323 unsigned int i;
324
325 spi_bitbang_stop(&hw->bitbang);
326 for (i = 0; i < hw->gpio_cs_count; i++)
327 gpio_free(hw->gpio_cs[i]);
328 spi_master_put(master);
329 return 0;
330 }
331
332 #ifdef CONFIG_OF
333 static const struct of_device_id tiny_spi_match[] = {
334 { .compatible = "opencores,tiny-spi-rtlsvn2", },
335 {},
336 };
337 MODULE_DEVICE_TABLE(of, tiny_spi_match);
338 #endif
339
340 static struct platform_driver tiny_spi_driver = {
341 .probe = tiny_spi_probe,
342 .remove = tiny_spi_remove,
343 .driver = {
344 .name = DRV_NAME,
345 .pm = NULL,
346 .of_match_table = of_match_ptr(tiny_spi_match),
347 },
348 };
349 module_platform_driver(tiny_spi_driver);
350
351 MODULE_DESCRIPTION("OpenCores tiny SPI driver");
352 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
353 MODULE_LICENSE("GPL");
354 MODULE_ALIAS("platform:" DRV_NAME);