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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * OpenCores tiny SPI host driver
4 *
5 * https://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>
13 */
14
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/of.h>
24
25#define DRV_NAME "spi_oc_tiny"
26
27#define TINY_SPI_RXDATA 0
28#define TINY_SPI_TXDATA 4
29#define TINY_SPI_STATUS 8
30#define TINY_SPI_CONTROL 12
31#define TINY_SPI_BAUD 16
32
33#define TINY_SPI_STATUS_TXE 0x1
34#define TINY_SPI_STATUS_TXR 0x2
35
36struct tiny_spi {
37 /* bitbang has to be first */
38 struct spi_bitbang bitbang;
39 struct completion done;
40
41 void __iomem *base;
42 int irq;
43 unsigned int freq;
44 unsigned int baudwidth;
45 unsigned int baud;
46 unsigned int speed_hz;
47 unsigned int mode;
48 unsigned int len;
49 unsigned int txc, rxc;
50 const u8 *txp;
51 u8 *rxp;
52};
53
54static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
55{
56 return spi_controller_get_devdata(sdev->controller);
57}
58
59static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
60{
61 struct tiny_spi *hw = tiny_spi_to_hw(spi);
62
63 return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
64}
65
66static int tiny_spi_setup_transfer(struct spi_device *spi,
67 struct spi_transfer *t)
68{
69 struct tiny_spi *hw = tiny_spi_to_hw(spi);
70 unsigned int baud = hw->baud;
71
72 if (t) {
73 if (t->speed_hz && t->speed_hz != hw->speed_hz)
74 baud = tiny_spi_baud(spi, t->speed_hz);
75 }
76 writel(baud, hw->base + TINY_SPI_BAUD);
77 writel(hw->mode, hw->base + TINY_SPI_CONTROL);
78 return 0;
79}
80
81static int tiny_spi_setup(struct spi_device *spi)
82{
83 struct tiny_spi *hw = tiny_spi_to_hw(spi);
84
85 if (spi->max_speed_hz != hw->speed_hz) {
86 hw->speed_hz = spi->max_speed_hz;
87 hw->baud = tiny_spi_baud(spi, hw->speed_hz);
88 }
89 hw->mode = spi->mode & SPI_MODE_X_MASK;
90 return 0;
91}
92
93static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
94{
95 while (!(readb(hw->base + TINY_SPI_STATUS) &
96 TINY_SPI_STATUS_TXR))
97 cpu_relax();
98}
99
100static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
101{
102 while (!(readb(hw->base + TINY_SPI_STATUS) &
103 TINY_SPI_STATUS_TXE))
104 cpu_relax();
105}
106
107static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
108{
109 struct tiny_spi *hw = tiny_spi_to_hw(spi);
110 const u8 *txp = t->tx_buf;
111 u8 *rxp = t->rx_buf;
112 unsigned int i;
113
114 if (hw->irq >= 0) {
115 /* use interrupt driven data transfer */
116 hw->len = t->len;
117 hw->txp = t->tx_buf;
118 hw->rxp = t->rx_buf;
119 hw->txc = 0;
120 hw->rxc = 0;
121
122 /* send the first byte */
123 if (t->len > 1) {
124 writeb(hw->txp ? *hw->txp++ : 0,
125 hw->base + TINY_SPI_TXDATA);
126 hw->txc++;
127 writeb(hw->txp ? *hw->txp++ : 0,
128 hw->base + TINY_SPI_TXDATA);
129 hw->txc++;
130 writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
131 } else {
132 writeb(hw->txp ? *hw->txp++ : 0,
133 hw->base + TINY_SPI_TXDATA);
134 hw->txc++;
135 writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
136 }
137
138 wait_for_completion(&hw->done);
139 } else {
140 /* we need to tighten the transfer loop */
141 writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
142 for (i = 1; i < t->len; i++) {
143 writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
144
145 if (rxp || (i != t->len - 1))
146 tiny_spi_wait_txr(hw);
147 if (rxp)
148 *rxp++ = readb(hw->base + TINY_SPI_TXDATA);
149 }
150 tiny_spi_wait_txe(hw);
151 if (rxp)
152 *rxp++ = readb(hw->base + TINY_SPI_RXDATA);
153 }
154
155 return t->len;
156}
157
158static irqreturn_t tiny_spi_irq(int irq, void *dev)
159{
160 struct tiny_spi *hw = dev;
161
162 writeb(0, hw->base + TINY_SPI_STATUS);
163 if (hw->rxc + 1 == hw->len) {
164 if (hw->rxp)
165 *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
166 hw->rxc++;
167 complete(&hw->done);
168 } else {
169 if (hw->rxp)
170 *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
171 hw->rxc++;
172 if (hw->txc < hw->len) {
173 writeb(hw->txp ? *hw->txp++ : 0,
174 hw->base + TINY_SPI_TXDATA);
175 hw->txc++;
176 writeb(TINY_SPI_STATUS_TXR,
177 hw->base + TINY_SPI_STATUS);
178 } else {
179 writeb(TINY_SPI_STATUS_TXE,
180 hw->base + TINY_SPI_STATUS);
181 }
182 }
183 return IRQ_HANDLED;
184}
185
186#ifdef CONFIG_OF
187static int tiny_spi_of_probe(struct platform_device *pdev)
188{
189 struct tiny_spi *hw = platform_get_drvdata(pdev);
190 struct device_node *np = pdev->dev.of_node;
191 u32 val;
192
193 if (!np)
194 return 0;
195 hw->bitbang.ctlr->dev.of_node = pdev->dev.of_node;
196 if (!of_property_read_u32(np, "clock-frequency", &val))
197 hw->freq = val;
198 if (!of_property_read_u32(np, "baud-width", &val))
199 hw->baudwidth = val;
200 return 0;
201}
202#else /* !CONFIG_OF */
203static int tiny_spi_of_probe(struct platform_device *pdev)
204{
205 return 0;
206}
207#endif /* CONFIG_OF */
208
209static int tiny_spi_probe(struct platform_device *pdev)
210{
211 struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
212 struct tiny_spi *hw;
213 struct spi_controller *host;
214 int err = -ENODEV;
215
216 host = spi_alloc_host(&pdev->dev, sizeof(struct tiny_spi));
217 if (!host)
218 return err;
219
220 /* setup the host state. */
221 host->bus_num = pdev->id;
222 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
223 host->setup = tiny_spi_setup;
224 host->use_gpio_descriptors = true;
225
226 hw = spi_controller_get_devdata(host);
227 platform_set_drvdata(pdev, hw);
228
229 /* setup the state for the bitbang driver */
230 hw->bitbang.ctlr = host;
231 hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
232 hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
233
234 /* find and map our resources */
235 hw->base = devm_platform_ioremap_resource(pdev, 0);
236 if (IS_ERR(hw->base)) {
237 err = PTR_ERR(hw->base);
238 goto exit;
239 }
240 /* irq is optional */
241 hw->irq = platform_get_irq(pdev, 0);
242 if (hw->irq >= 0) {
243 init_completion(&hw->done);
244 err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
245 pdev->name, hw);
246 if (err)
247 goto exit;
248 }
249 /* find platform data */
250 if (platp) {
251 hw->freq = platp->freq;
252 hw->baudwidth = platp->baudwidth;
253 } else {
254 err = tiny_spi_of_probe(pdev);
255 if (err)
256 goto exit;
257 }
258
259 /* register our spi controller */
260 err = spi_bitbang_start(&hw->bitbang);
261 if (err)
262 goto exit;
263 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
264
265 return 0;
266
267exit:
268 spi_controller_put(host);
269 return err;
270}
271
272static void tiny_spi_remove(struct platform_device *pdev)
273{
274 struct tiny_spi *hw = platform_get_drvdata(pdev);
275 struct spi_controller *host = hw->bitbang.ctlr;
276
277 spi_bitbang_stop(&hw->bitbang);
278 spi_controller_put(host);
279}
280
281#ifdef CONFIG_OF
282static const struct of_device_id tiny_spi_match[] = {
283 { .compatible = "opencores,tiny-spi-rtlsvn2", },
284 {},
285};
286MODULE_DEVICE_TABLE(of, tiny_spi_match);
287#endif /* CONFIG_OF */
288
289static struct platform_driver tiny_spi_driver = {
290 .probe = tiny_spi_probe,
291 .remove = tiny_spi_remove,
292 .driver = {
293 .name = DRV_NAME,
294 .pm = NULL,
295 .of_match_table = of_match_ptr(tiny_spi_match),
296 },
297};
298module_platform_driver(tiny_spi_driver);
299
300MODULE_DESCRIPTION("OpenCores tiny SPI driver");
301MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
302MODULE_LICENSE("GPL");
303MODULE_ALIAS("platform:" DRV_NAME);
1// SPDX-License-Identifier: GPL-2.0-only
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>
13 */
14
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
37struct 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;
53 int gpio_cs_count;
54 int *gpio_cs;
55};
56
57static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
58{
59 return spi_master_get_devdata(sdev->master);
60}
61
62static 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
69static 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
79static 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
94static 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
106static 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
113static 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
120static 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 /* use interrupt driven data transfer */
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);
152 } else {
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))
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
171static 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
202static 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 /* !CONFIG_OF */
232static int tiny_spi_of_probe(struct platform_device *pdev)
233{
234 return 0;
235}
236#endif /* CONFIG_OF */
237
238static 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 /* setup the master state. */
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 /* setup the state for the bitbang driver */
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 /* find and map our resources */
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 /* irq is optional */
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 /* find platform data */
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 /* register our spi controller */
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
311exit_gpio:
312 while (i-- > 0)
313 gpio_free(hw->gpio_cs[i]);
314exit:
315 spi_master_put(master);
316 return err;
317}
318
319static 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
333static const struct of_device_id tiny_spi_match[] = {
334 { .compatible = "opencores,tiny-spi-rtlsvn2", },
335 {},
336};
337MODULE_DEVICE_TABLE(of, tiny_spi_match);
338#endif /* CONFIG_OF */
339
340static 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};
349module_platform_driver(tiny_spi_driver);
350
351MODULE_DESCRIPTION("OpenCores tiny SPI driver");
352MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
353MODULE_LICENSE("GPL");
354MODULE_ALIAS("platform:" DRV_NAME);