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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
187#include <linux/of_gpio.h>
188
189static int tiny_spi_of_probe(struct platform_device *pdev)
190{
191 struct tiny_spi *hw = platform_get_drvdata(pdev);
192 struct device_node *np = pdev->dev.of_node;
193 u32 val;
194
195 if (!np)
196 return 0;
197 hw->bitbang.master->dev.of_node = pdev->dev.of_node;
198 if (!of_property_read_u32(np, "clock-frequency", &val))
199 hw->freq = val;
200 if (!of_property_read_u32(np, "baud-width", &val))
201 hw->baudwidth = val;
202 return 0;
203}
204#else /* !CONFIG_OF */
205static int tiny_spi_of_probe(struct platform_device *pdev)
206{
207 return 0;
208}
209#endif /* CONFIG_OF */
210
211static int tiny_spi_probe(struct platform_device *pdev)
212{
213 struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
214 struct tiny_spi *hw;
215 struct spi_controller *host;
216 int err = -ENODEV;
217
218 host = spi_alloc_host(&pdev->dev, sizeof(struct tiny_spi));
219 if (!host)
220 return err;
221
222 /* setup the host state. */
223 host->bus_num = pdev->id;
224 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
225 host->setup = tiny_spi_setup;
226 host->use_gpio_descriptors = true;
227
228 hw = spi_controller_get_devdata(host);
229 platform_set_drvdata(pdev, hw);
230
231 /* setup the state for the bitbang driver */
232 hw->bitbang.master = host;
233 hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
234 hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
235
236 /* find and map our resources */
237 hw->base = devm_platform_ioremap_resource(pdev, 0);
238 if (IS_ERR(hw->base)) {
239 err = PTR_ERR(hw->base);
240 goto exit;
241 }
242 /* irq is optional */
243 hw->irq = platform_get_irq(pdev, 0);
244 if (hw->irq >= 0) {
245 init_completion(&hw->done);
246 err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
247 pdev->name, hw);
248 if (err)
249 goto exit;
250 }
251 /* find platform data */
252 if (platp) {
253 hw->freq = platp->freq;
254 hw->baudwidth = platp->baudwidth;
255 } else {
256 err = tiny_spi_of_probe(pdev);
257 if (err)
258 goto exit;
259 }
260
261 /* register our spi controller */
262 err = spi_bitbang_start(&hw->bitbang);
263 if (err)
264 goto exit;
265 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
266
267 return 0;
268
269exit:
270 spi_controller_put(host);
271 return err;
272}
273
274static void tiny_spi_remove(struct platform_device *pdev)
275{
276 struct tiny_spi *hw = platform_get_drvdata(pdev);
277 struct spi_controller *host = hw->bitbang.master;
278
279 spi_bitbang_stop(&hw->bitbang);
280 spi_controller_put(host);
281}
282
283#ifdef CONFIG_OF
284static const struct of_device_id tiny_spi_match[] = {
285 { .compatible = "opencores,tiny-spi-rtlsvn2", },
286 {},
287};
288MODULE_DEVICE_TABLE(of, tiny_spi_match);
289#endif /* CONFIG_OF */
290
291static struct platform_driver tiny_spi_driver = {
292 .probe = tiny_spi_probe,
293 .remove_new = tiny_spi_remove,
294 .driver = {
295 .name = DRV_NAME,
296 .pm = NULL,
297 .of_match_table = of_match_ptr(tiny_spi_match),
298 },
299};
300module_platform_driver(tiny_spi_driver);
301
302MODULE_DESCRIPTION("OpenCores tiny SPI driver");
303MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
304MODULE_LICENSE("GPL");
305MODULE_ALIAS("platform:" DRV_NAME);
1/*
2 * OpenCores tiny SPI master driver
3 *
4 * http://opencores.org/project,tiny_spi
5 *
6 * Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw>
7 *
8 * Based on spi_s3c24xx.c, which is:
9 * Copyright (c) 2006 Ben Dooks
10 * Copyright (c) 2006 Simtec Electronics
11 * Ben Dooks <ben@simtec.co.uk>
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 */
17
18#include <linux/interrupt.h>
19#include <linux/errno.h>
20#include <linux/module.h>
21#include <linux/platform_device.h>
22#include <linux/spi/spi.h>
23#include <linux/spi/spi_bitbang.h>
24#include <linux/spi/spi_oc_tiny.h>
25#include <linux/io.h>
26#include <linux/gpio.h>
27#include <linux/of.h>
28
29#define DRV_NAME "spi_oc_tiny"
30
31#define TINY_SPI_RXDATA 0
32#define TINY_SPI_TXDATA 4
33#define TINY_SPI_STATUS 8
34#define TINY_SPI_CONTROL 12
35#define TINY_SPI_BAUD 16
36
37#define TINY_SPI_STATUS_TXE 0x1
38#define TINY_SPI_STATUS_TXR 0x2
39
40struct tiny_spi {
41 /* bitbang has to be first */
42 struct spi_bitbang bitbang;
43 struct completion done;
44
45 void __iomem *base;
46 int irq;
47 unsigned int freq;
48 unsigned int baudwidth;
49 unsigned int baud;
50 unsigned int speed_hz;
51 unsigned int mode;
52 unsigned int len;
53 unsigned int txc, rxc;
54 const u8 *txp;
55 u8 *rxp;
56 int gpio_cs_count;
57 int *gpio_cs;
58};
59
60static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
61{
62 return spi_master_get_devdata(sdev->master);
63}
64
65static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
66{
67 struct tiny_spi *hw = tiny_spi_to_hw(spi);
68
69 return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
70}
71
72static void tiny_spi_chipselect(struct spi_device *spi, int is_active)
73{
74 struct tiny_spi *hw = tiny_spi_to_hw(spi);
75
76 if (hw->gpio_cs_count > 0) {
77 gpio_set_value(hw->gpio_cs[spi->chip_select],
78 (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
79 }
80}
81
82static int tiny_spi_setup_transfer(struct spi_device *spi,
83 struct spi_transfer *t)
84{
85 struct tiny_spi *hw = tiny_spi_to_hw(spi);
86 unsigned int baud = hw->baud;
87
88 if (t) {
89 if (t->speed_hz && t->speed_hz != hw->speed_hz)
90 baud = tiny_spi_baud(spi, t->speed_hz);
91 }
92 writel(baud, hw->base + TINY_SPI_BAUD);
93 writel(hw->mode, hw->base + TINY_SPI_CONTROL);
94 return 0;
95}
96
97static int tiny_spi_setup(struct spi_device *spi)
98{
99 struct tiny_spi *hw = tiny_spi_to_hw(spi);
100
101 if (spi->max_speed_hz != hw->speed_hz) {
102 hw->speed_hz = spi->max_speed_hz;
103 hw->baud = tiny_spi_baud(spi, hw->speed_hz);
104 }
105 hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA);
106 return 0;
107}
108
109static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
110{
111 while (!(readb(hw->base + TINY_SPI_STATUS) &
112 TINY_SPI_STATUS_TXR))
113 cpu_relax();
114}
115
116static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
117{
118 while (!(readb(hw->base + TINY_SPI_STATUS) &
119 TINY_SPI_STATUS_TXE))
120 cpu_relax();
121}
122
123static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
124{
125 struct tiny_spi *hw = tiny_spi_to_hw(spi);
126 const u8 *txp = t->tx_buf;
127 u8 *rxp = t->rx_buf;
128 unsigned int i;
129
130 if (hw->irq >= 0) {
131 /* use interrupt driven data transfer */
132 hw->len = t->len;
133 hw->txp = t->tx_buf;
134 hw->rxp = t->rx_buf;
135 hw->txc = 0;
136 hw->rxc = 0;
137
138 /* send the first byte */
139 if (t->len > 1) {
140 writeb(hw->txp ? *hw->txp++ : 0,
141 hw->base + TINY_SPI_TXDATA);
142 hw->txc++;
143 writeb(hw->txp ? *hw->txp++ : 0,
144 hw->base + TINY_SPI_TXDATA);
145 hw->txc++;
146 writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
147 } else {
148 writeb(hw->txp ? *hw->txp++ : 0,
149 hw->base + TINY_SPI_TXDATA);
150 hw->txc++;
151 writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
152 }
153
154 wait_for_completion(&hw->done);
155 } else {
156 /* we need to tighten the transfer loop */
157 writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
158 for (i = 1; i < t->len; i++) {
159 writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
160
161 if (rxp || (i != t->len - 1))
162 tiny_spi_wait_txr(hw);
163 if (rxp)
164 *rxp++ = readb(hw->base + TINY_SPI_TXDATA);
165 }
166 tiny_spi_wait_txe(hw);
167 if (rxp)
168 *rxp++ = readb(hw->base + TINY_SPI_RXDATA);
169 }
170
171 return t->len;
172}
173
174static irqreturn_t tiny_spi_irq(int irq, void *dev)
175{
176 struct tiny_spi *hw = dev;
177
178 writeb(0, hw->base + TINY_SPI_STATUS);
179 if (hw->rxc + 1 == hw->len) {
180 if (hw->rxp)
181 *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
182 hw->rxc++;
183 complete(&hw->done);
184 } else {
185 if (hw->rxp)
186 *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
187 hw->rxc++;
188 if (hw->txc < hw->len) {
189 writeb(hw->txp ? *hw->txp++ : 0,
190 hw->base + TINY_SPI_TXDATA);
191 hw->txc++;
192 writeb(TINY_SPI_STATUS_TXR,
193 hw->base + TINY_SPI_STATUS);
194 } else {
195 writeb(TINY_SPI_STATUS_TXE,
196 hw->base + TINY_SPI_STATUS);
197 }
198 }
199 return IRQ_HANDLED;
200}
201
202#ifdef CONFIG_OF
203#include <linux/of_gpio.h>
204
205static int tiny_spi_of_probe(struct platform_device *pdev)
206{
207 struct tiny_spi *hw = platform_get_drvdata(pdev);
208 struct device_node *np = pdev->dev.of_node;
209 unsigned int i;
210 const __be32 *val;
211 int len;
212
213 if (!np)
214 return 0;
215 hw->gpio_cs_count = of_gpio_count(np);
216 if (hw->gpio_cs_count > 0) {
217 hw->gpio_cs = devm_kzalloc(&pdev->dev,
218 hw->gpio_cs_count * sizeof(unsigned int),
219 GFP_KERNEL);
220 if (!hw->gpio_cs)
221 return -ENOMEM;
222 }
223 for (i = 0; i < hw->gpio_cs_count; i++) {
224 hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL);
225 if (hw->gpio_cs[i] < 0)
226 return -ENODEV;
227 }
228 hw->bitbang.master->dev.of_node = pdev->dev.of_node;
229 val = of_get_property(pdev->dev.of_node,
230 "clock-frequency", &len);
231 if (val && len >= sizeof(__be32))
232 hw->freq = be32_to_cpup(val);
233 val = of_get_property(pdev->dev.of_node, "baud-width", &len);
234 if (val && len >= sizeof(__be32))
235 hw->baudwidth = be32_to_cpup(val);
236 return 0;
237}
238#else /* !CONFIG_OF */
239static int tiny_spi_of_probe(struct platform_device *pdev)
240{
241 return 0;
242}
243#endif /* CONFIG_OF */
244
245static int tiny_spi_probe(struct platform_device *pdev)
246{
247 struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
248 struct tiny_spi *hw;
249 struct spi_master *master;
250 struct resource *res;
251 unsigned int i;
252 int err = -ENODEV;
253
254 master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi));
255 if (!master)
256 return err;
257
258 /* setup the master state. */
259 master->bus_num = pdev->id;
260 master->num_chipselect = 255;
261 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
262 master->setup = tiny_spi_setup;
263
264 hw = spi_master_get_devdata(master);
265 platform_set_drvdata(pdev, hw);
266
267 /* setup the state for the bitbang driver */
268 hw->bitbang.master = master;
269 hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
270 hw->bitbang.chipselect = tiny_spi_chipselect;
271 hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
272
273 /* find and map our resources */
274 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
275 hw->base = devm_ioremap_resource(&pdev->dev, res);
276 if (IS_ERR(hw->base)) {
277 err = PTR_ERR(hw->base);
278 goto exit;
279 }
280 /* irq is optional */
281 hw->irq = platform_get_irq(pdev, 0);
282 if (hw->irq >= 0) {
283 init_completion(&hw->done);
284 err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
285 pdev->name, hw);
286 if (err)
287 goto exit;
288 }
289 /* find platform data */
290 if (platp) {
291 hw->gpio_cs_count = platp->gpio_cs_count;
292 hw->gpio_cs = platp->gpio_cs;
293 if (platp->gpio_cs_count && !platp->gpio_cs) {
294 err = -EBUSY;
295 goto exit;
296 }
297 hw->freq = platp->freq;
298 hw->baudwidth = platp->baudwidth;
299 } else {
300 err = tiny_spi_of_probe(pdev);
301 if (err)
302 goto exit;
303 }
304 for (i = 0; i < hw->gpio_cs_count; i++) {
305 err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev));
306 if (err)
307 goto exit_gpio;
308 gpio_direction_output(hw->gpio_cs[i], 1);
309 }
310 hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count);
311
312 /* register our spi controller */
313 err = spi_bitbang_start(&hw->bitbang);
314 if (err)
315 goto exit;
316 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
317
318 return 0;
319
320exit_gpio:
321 while (i-- > 0)
322 gpio_free(hw->gpio_cs[i]);
323exit:
324 spi_master_put(master);
325 return err;
326}
327
328static int tiny_spi_remove(struct platform_device *pdev)
329{
330 struct tiny_spi *hw = platform_get_drvdata(pdev);
331 struct spi_master *master = hw->bitbang.master;
332 unsigned int i;
333
334 spi_bitbang_stop(&hw->bitbang);
335 for (i = 0; i < hw->gpio_cs_count; i++)
336 gpio_free(hw->gpio_cs[i]);
337 spi_master_put(master);
338 return 0;
339}
340
341#ifdef CONFIG_OF
342static const struct of_device_id tiny_spi_match[] = {
343 { .compatible = "opencores,tiny-spi-rtlsvn2", },
344 {},
345};
346MODULE_DEVICE_TABLE(of, tiny_spi_match);
347#endif /* CONFIG_OF */
348
349static struct platform_driver tiny_spi_driver = {
350 .probe = tiny_spi_probe,
351 .remove = tiny_spi_remove,
352 .driver = {
353 .name = DRV_NAME,
354 .owner = THIS_MODULE,
355 .pm = NULL,
356 .of_match_table = of_match_ptr(tiny_spi_match),
357 },
358};
359module_platform_driver(tiny_spi_driver);
360
361MODULE_DESCRIPTION("OpenCores tiny SPI driver");
362MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
363MODULE_LICENSE("GPL");
364MODULE_ALIAS("platform:" DRV_NAME);