Commit | Line | Data |
---|---|---|
d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
ce792580 TC |
2 | /* |
3 | * OpenCores tiny SPI master driver | |
4 | * | |
5 | * http://opencores.org/project,tiny_spi | |
6 | * | |
7 | * Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw> | |
8 | * | |
9 | * Based on spi_s3c24xx.c, which is: | |
10 | * Copyright (c) 2006 Ben Dooks | |
11 | * Copyright (c) 2006 Simtec Electronics | |
12 | * Ben Dooks <ben@simtec.co.uk> | |
ce792580 TC |
13 | */ |
14 | ||
ce792580 TC |
15 | #include <linux/interrupt.h> |
16 | #include <linux/errno.h> | |
d7614de4 | 17 | #include <linux/module.h> |
ce792580 TC |
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 | /* bitbang has to be first */ | |
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; | |
e80beb27 | 53 | int gpio_cs_count; |
ce792580 TC |
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 | ||
e80beb27 | 73 | if (hw->gpio_cs_count > 0) { |
ce792580 TC |
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) { | |
886db6ac | 128 | /* use interrupt driven data transfer */ |
ce792580 TC |
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 | /* send the first byte */ | |
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); | |
ce792580 | 152 | } else { |
e826a7ff AL |
153 | /* we need to tighten the transfer loop */ |
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)) | |
ce792580 | 159 | tiny_spi_wait_txr(hw); |
e826a7ff AL |
160 | if (rxp) |
161 | *rxp++ = readb(hw->base + TINY_SPI_TXDATA); | |
ce792580 TC |
162 | } |
163 | tiny_spi_wait_txe(hw); | |
e826a7ff AL |
164 | if (rxp) |
165 | *rxp++ = readb(hw->base + TINY_SPI_RXDATA); | |
ce792580 | 166 | } |
e826a7ff | 167 | |
ce792580 TC |
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 | ||
fd4a319b | 202 | static int tiny_spi_of_probe(struct platform_device *pdev) |
ce792580 TC |
203 | { |
204 | struct tiny_spi *hw = platform_get_drvdata(pdev); | |
205 | struct device_node *np = pdev->dev.of_node; | |
206 | unsigned int i; | |
45a3e771 | 207 | u32 val; |
ce792580 TC |
208 | |
209 | if (!np) | |
210 | return 0; | |
211 | hw->gpio_cs_count = of_gpio_count(np); | |
e80beb27 | 212 | if (hw->gpio_cs_count > 0) { |
a86854d0 KC |
213 | hw->gpio_cs = devm_kcalloc(&pdev->dev, |
214 | hw->gpio_cs_count, sizeof(unsigned int), | |
ce792580 TC |
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; | |
45a3e771 TK |
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; | |
ce792580 TC |
229 | return 0; |
230 | } | |
231 | #else /* !CONFIG_OF */ | |
fd4a319b | 232 | static int tiny_spi_of_probe(struct platform_device *pdev) |
ce792580 TC |
233 | { |
234 | return 0; | |
235 | } | |
236 | #endif /* CONFIG_OF */ | |
237 | ||
fd4a319b | 238 | static int tiny_spi_probe(struct platform_device *pdev) |
ce792580 | 239 | { |
8074cf06 | 240 | struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev); |
ce792580 TC |
241 | struct tiny_spi *hw; |
242 | struct spi_master *master; | |
243 | struct resource *res; | |
244 | unsigned int i; | |
245 | int err = -ENODEV; | |
246 | ||
247 | master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi)); | |
248 | if (!master) | |
249 | return err; | |
250 | ||
251 | /* setup the master state. */ | |
252 | master->bus_num = pdev->id; | |
253 | master->num_chipselect = 255; | |
254 | master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; | |
255 | master->setup = tiny_spi_setup; | |
256 | ||
257 | hw = spi_master_get_devdata(master); | |
258 | platform_set_drvdata(pdev, hw); | |
259 | ||
260 | /* setup the state for the bitbang driver */ | |
94c69f76 | 261 | hw->bitbang.master = master; |
ce792580 TC |
262 | hw->bitbang.setup_transfer = tiny_spi_setup_transfer; |
263 | hw->bitbang.chipselect = tiny_spi_chipselect; | |
264 | hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs; | |
265 | ||
266 | /* find and map our resources */ | |
267 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
b3136f8f JL |
268 | hw->base = devm_ioremap_resource(&pdev->dev, res); |
269 | if (IS_ERR(hw->base)) { | |
270 | err = PTR_ERR(hw->base); | |
271 | goto exit; | |
272 | } | |
ce792580 TC |
273 | /* irq is optional */ |
274 | hw->irq = platform_get_irq(pdev, 0); | |
275 | if (hw->irq >= 0) { | |
276 | init_completion(&hw->done); | |
277 | err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0, | |
278 | pdev->name, hw); | |
279 | if (err) | |
280 | goto exit; | |
281 | } | |
282 | /* find platform data */ | |
283 | if (platp) { | |
284 | hw->gpio_cs_count = platp->gpio_cs_count; | |
285 | hw->gpio_cs = platp->gpio_cs; | |
b3136f8f JL |
286 | if (platp->gpio_cs_count && !platp->gpio_cs) { |
287 | err = -EBUSY; | |
288 | goto exit; | |
289 | } | |
ce792580 TC |
290 | hw->freq = platp->freq; |
291 | hw->baudwidth = platp->baudwidth; | |
292 | } else { | |
293 | err = tiny_spi_of_probe(pdev); | |
294 | if (err) | |
295 | goto exit; | |
296 | } | |
297 | for (i = 0; i < hw->gpio_cs_count; i++) { | |
298 | err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev)); | |
299 | if (err) | |
300 | goto exit_gpio; | |
301 | gpio_direction_output(hw->gpio_cs[i], 1); | |
302 | } | |
e80beb27 | 303 | hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count); |
ce792580 TC |
304 | |
305 | /* register our spi controller */ | |
306 | err = spi_bitbang_start(&hw->bitbang); | |
307 | if (err) | |
308 | goto exit; | |
309 | dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); | |
310 | ||
311 | return 0; | |
312 | ||
313 | exit_gpio: | |
314 | while (i-- > 0) | |
315 | gpio_free(hw->gpio_cs[i]); | |
ce792580 | 316 | exit: |
ce792580 TC |
317 | spi_master_put(master); |
318 | return err; | |
319 | } | |
320 | ||
fd4a319b | 321 | static int tiny_spi_remove(struct platform_device *pdev) |
ce792580 TC |
322 | { |
323 | struct tiny_spi *hw = platform_get_drvdata(pdev); | |
324 | struct spi_master *master = hw->bitbang.master; | |
325 | unsigned int i; | |
326 | ||
327 | spi_bitbang_stop(&hw->bitbang); | |
328 | for (i = 0; i < hw->gpio_cs_count; i++) | |
329 | gpio_free(hw->gpio_cs[i]); | |
ce792580 TC |
330 | spi_master_put(master); |
331 | return 0; | |
332 | } | |
333 | ||
334 | #ifdef CONFIG_OF | |
335 | static const struct of_device_id tiny_spi_match[] = { | |
336 | { .compatible = "opencores,tiny-spi-rtlsvn2", }, | |
337 | {}, | |
338 | }; | |
339 | MODULE_DEVICE_TABLE(of, tiny_spi_match); | |
ce792580 TC |
340 | #endif /* CONFIG_OF */ |
341 | ||
342 | static struct platform_driver tiny_spi_driver = { | |
343 | .probe = tiny_spi_probe, | |
fd4a319b | 344 | .remove = tiny_spi_remove, |
ce792580 TC |
345 | .driver = { |
346 | .name = DRV_NAME, | |
ce792580 | 347 | .pm = NULL, |
9547acce | 348 | .of_match_table = of_match_ptr(tiny_spi_match), |
ce792580 TC |
349 | }, |
350 | }; | |
940ab889 | 351 | module_platform_driver(tiny_spi_driver); |
ce792580 TC |
352 | |
353 | MODULE_DESCRIPTION("OpenCores tiny SPI driver"); | |
354 | MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); | |
355 | MODULE_LICENSE("GPL"); | |
356 | MODULE_ALIAS("platform:" DRV_NAME); |