1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012-2013 Uwe Kleine-Koenig for Pengutronix
4 */
5#include <linux/kernel.h>
6#include <linux/io.h>
7#include <linux/spi/spi.h>
8#include <linux/spi/spi_bitbang.h>
9#include <linux/interrupt.h>
10#include <linux/platform_device.h>
11#include <linux/clk.h>
12#include <linux/err.h>
13#include <linux/module.h>
14#include <linux/platform_data/efm32-spi.h>
15#include <linux/of.h>
16
17#define DRIVER_NAME "efm32-spi"
18
19#define MASK_VAL(mask, val)		((val << __ffs(mask)) & mask)
20
21#define REG_CTRL		0x00
22#define REG_CTRL_SYNC			0x0001
23#define REG_CTRL_CLKPOL			0x0100
24#define REG_CTRL_CLKPHA			0x0200
25#define REG_CTRL_MSBF			0x0400
26#define REG_CTRL_TXBIL			0x1000
27
28#define REG_FRAME		0x04
29#define REG_FRAME_DATABITS__MASK	0x000f
30#define REG_FRAME_DATABITS(n)		((n) - 3)
31
32#define REG_CMD			0x0c
33#define REG_CMD_RXEN			0x0001
34#define REG_CMD_RXDIS			0x0002
35#define REG_CMD_TXEN			0x0004
36#define REG_CMD_TXDIS			0x0008
37#define REG_CMD_MASTEREN		0x0010
38
39#define REG_STATUS		0x10
40#define REG_STATUS_TXENS		0x0002
41#define REG_STATUS_TXC			0x0020
42#define REG_STATUS_TXBL			0x0040
43#define REG_STATUS_RXDATAV		0x0080
44
45#define REG_CLKDIV		0x14
46
47#define REG_RXDATAX		0x18
48#define REG_RXDATAX_RXDATA__MASK	0x01ff
49#define REG_RXDATAX_PERR		0x4000
50#define REG_RXDATAX_FERR		0x8000
51
52#define REG_TXDATA		0x34
53
54#define REG_IF		0x40
55#define REG_IF_TXBL			0x0002
56#define REG_IF_RXDATAV			0x0004
57
58#define REG_IFS		0x44
59#define REG_IFC		0x48
60#define REG_IEN		0x4c
61
62#define REG_ROUTE		0x54
63#define REG_ROUTE_RXPEN			0x0001
64#define REG_ROUTE_TXPEN			0x0002
65#define REG_ROUTE_CLKPEN		0x0008
66#define REG_ROUTE_LOCATION__MASK	0x0700
67#define REG_ROUTE_LOCATION(n)		MASK_VAL(REG_ROUTE_LOCATION__MASK, (n))
68
69struct efm32_spi_ddata {
70	struct spi_bitbang bitbang;
71
72	spinlock_t lock;
73
74	struct clk *clk;
75	void __iomem *base;
76	unsigned int rxirq, txirq;
77	struct efm32_spi_pdata pdata;
78
79	/* irq data */
80	struct completion done;
81	const u8 *tx_buf;
82	u8 *rx_buf;
83	unsigned tx_len, rx_len;
84};
85
86#define ddata_to_dev(ddata)	(&(ddata->bitbang.master->dev))
87#define efm32_spi_vdbg(ddata, format, arg...)	\
88	dev_vdbg(ddata_to_dev(ddata), format, ##arg)
89
90static void efm32_spi_write32(struct efm32_spi_ddata *ddata,
91		u32 value, unsigned offset)
92{
93	writel_relaxed(value, ddata->base + offset);
94}
95
96static u32 efm32_spi_read32(struct efm32_spi_ddata *ddata, unsigned offset)
97{
98	return readl_relaxed(ddata->base + offset);
99}
100
101static int efm32_spi_setup_transfer(struct spi_device *spi,
102		struct spi_transfer *t)
103{
104	struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
105
106	unsigned bpw = t->bits_per_word ?: spi->bits_per_word;
107	unsigned speed = t->speed_hz ?: spi->max_speed_hz;
108	unsigned long clkfreq = clk_get_rate(ddata->clk);
109	u32 clkdiv;
110
111	efm32_spi_write32(ddata, REG_CTRL_SYNC | REG_CTRL_MSBF |
112			(spi->mode & SPI_CPHA ? REG_CTRL_CLKPHA : 0) |
113			(spi->mode & SPI_CPOL ? REG_CTRL_CLKPOL : 0), REG_CTRL);
114
115	efm32_spi_write32(ddata,
116			REG_FRAME_DATABITS(bpw), REG_FRAME);
117
118	if (2 * speed >= clkfreq)
119		clkdiv = 0;
120	else
121		clkdiv = 64 * (DIV_ROUND_UP(2 * clkfreq, speed) - 4);
122
123	if (clkdiv > (1U << 21))
124		return -EINVAL;
125
126	efm32_spi_write32(ddata, clkdiv, REG_CLKDIV);
127	efm32_spi_write32(ddata, REG_CMD_MASTEREN, REG_CMD);
128	efm32_spi_write32(ddata, REG_CMD_RXEN | REG_CMD_TXEN, REG_CMD);
129
130	return 0;
131}
132
133static void efm32_spi_tx_u8(struct efm32_spi_ddata *ddata)
134{
135	u8 val = 0;
136
137	if (ddata->tx_buf) {
138		val = *ddata->tx_buf;
139		ddata->tx_buf++;
140	}
141
142	ddata->tx_len--;
143	efm32_spi_write32(ddata, val, REG_TXDATA);
144	efm32_spi_vdbg(ddata, "%s: tx 0x%x\n", __func__, val);
145}
146
147static void efm32_spi_rx_u8(struct efm32_spi_ddata *ddata)
148{
149	u32 rxdata = efm32_spi_read32(ddata, REG_RXDATAX);
150	efm32_spi_vdbg(ddata, "%s: rx 0x%x\n", __func__, rxdata);
151
152	if (ddata->rx_buf) {
153		*ddata->rx_buf = rxdata;
154		ddata->rx_buf++;
155	}
156
157	ddata->rx_len--;
158}
159
160static void efm32_spi_filltx(struct efm32_spi_ddata *ddata)
161{
162	while (ddata->tx_len &&
163			ddata->tx_len + 2 > ddata->rx_len &&
164			efm32_spi_read32(ddata, REG_STATUS) & REG_STATUS_TXBL) {
165		efm32_spi_tx_u8(ddata);
166	}
167}
168
169static int efm32_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
170{
171	struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
172	int ret = -EBUSY;
173
174	spin_lock_irq(&ddata->lock);
175
176	if (ddata->tx_buf || ddata->rx_buf)
177		goto out_unlock;
178
179	ddata->tx_buf = t->tx_buf;
180	ddata->rx_buf = t->rx_buf;
181	ddata->tx_len = ddata->rx_len =
182		t->len * DIV_ROUND_UP(t->bits_per_word, 8);
183
184	efm32_spi_filltx(ddata);
185
186	reinit_completion(&ddata->done);
187
188	efm32_spi_write32(ddata, REG_IF_TXBL | REG_IF_RXDATAV, REG_IEN);
189
190	spin_unlock_irq(&ddata->lock);
191
192	wait_for_completion(&ddata->done);
193
194	spin_lock_irq(&ddata->lock);
195
196	ret = t->len - max(ddata->tx_len, ddata->rx_len);
197
198	efm32_spi_write32(ddata, 0, REG_IEN);
199	ddata->tx_buf = ddata->rx_buf = NULL;
200
201out_unlock:
202	spin_unlock_irq(&ddata->lock);
203
204	return ret;
205}
206
207static irqreturn_t efm32_spi_rxirq(int irq, void *data)
208{
209	struct efm32_spi_ddata *ddata = data;
210	irqreturn_t ret = IRQ_NONE;
211
212	spin_lock(&ddata->lock);
213
214	while (ddata->rx_len > 0 &&
215			efm32_spi_read32(ddata, REG_STATUS) &
216			REG_STATUS_RXDATAV) {
217		efm32_spi_rx_u8(ddata);
218
219		ret = IRQ_HANDLED;
220	}
221
222	if (!ddata->rx_len) {
223		u32 ien = efm32_spi_read32(ddata, REG_IEN);
224
225		ien &= ~REG_IF_RXDATAV;
226
227		efm32_spi_write32(ddata, ien, REG_IEN);
228
229		complete(&ddata->done);
230	}
231
232	spin_unlock(&ddata->lock);
233
234	return ret;
235}
236
237static irqreturn_t efm32_spi_txirq(int irq, void *data)
238{
239	struct efm32_spi_ddata *ddata = data;
240
241	efm32_spi_vdbg(ddata,
242			"%s: txlen = %u, rxlen = %u, if=0x%08x, stat=0x%08x\n",
243			__func__, ddata->tx_len, ddata->rx_len,
244			efm32_spi_read32(ddata, REG_IF),
245			efm32_spi_read32(ddata, REG_STATUS));
246
247	spin_lock(&ddata->lock);
248
249	efm32_spi_filltx(ddata);
250
251	efm32_spi_vdbg(ddata, "%s: txlen = %u, rxlen = %u\n",
252			__func__, ddata->tx_len, ddata->rx_len);
253
254	if (!ddata->tx_len) {
255		u32 ien = efm32_spi_read32(ddata, REG_IEN);
256
257		ien &= ~REG_IF_TXBL;
258
259		efm32_spi_write32(ddata, ien, REG_IEN);
260		efm32_spi_vdbg(ddata, "disable TXBL\n");
261	}
262
263	spin_unlock(&ddata->lock);
264
265	return IRQ_HANDLED;
266}
267
268static u32 efm32_spi_get_configured_location(struct efm32_spi_ddata *ddata)
269{
270	u32 reg = efm32_spi_read32(ddata, REG_ROUTE);
271
272	return (reg & REG_ROUTE_LOCATION__MASK) >> __ffs(REG_ROUTE_LOCATION__MASK);
273}
274
275static void efm32_spi_probe_dt(struct platform_device *pdev,
276		struct spi_master *master, struct efm32_spi_ddata *ddata)
277{
278	struct device_node *np = pdev->dev.of_node;
279	u32 location;
280	int ret;
281
282	ret = of_property_read_u32(np, "energymicro,location", &location);
283
284	if (ret)
285		/* fall back to wrongly namespaced property */
286		ret = of_property_read_u32(np, "efm32,location", &location);
287
288	if (ret)
289		/* fall back to old and (wrongly) generic property "location" */
290		ret = of_property_read_u32(np, "location", &location);
291
292	if (!ret) {
293		dev_dbg(&pdev->dev, "using location %u\n", location);
294	} else {
295		/* default to location configured in hardware */
296		location = efm32_spi_get_configured_location(ddata);
297
298		dev_info(&pdev->dev, "fall back to location %u\n", location);
299	}
300
301	ddata->pdata.location = location;
302}
303
304static int efm32_spi_probe(struct platform_device *pdev)
305{
306	struct efm32_spi_ddata *ddata;
307	struct resource *res;
308	int ret;
309	struct spi_master *master;
310	struct device_node *np = pdev->dev.of_node;
311
312	if (!np)
313		return -EINVAL;
314
315	master = spi_alloc_master(&pdev->dev, sizeof(*ddata));
316	if (!master) {
317		dev_dbg(&pdev->dev,
318				"failed to allocate spi master controller\n");
319		return -ENOMEM;
320	}
321	platform_set_drvdata(pdev, master);
322
323	master->dev.of_node = pdev->dev.of_node;
324
325	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
326	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
327	master->use_gpio_descriptors = true;
328
329	ddata = spi_master_get_devdata(master);
330
331	ddata->bitbang.master = master;
332	ddata->bitbang.setup_transfer = efm32_spi_setup_transfer;
333	ddata->bitbang.txrx_bufs = efm32_spi_txrx_bufs;
334
335	spin_lock_init(&ddata->lock);
336	init_completion(&ddata->done);
337
338	ddata->clk = devm_clk_get(&pdev->dev, NULL);
339	if (IS_ERR(ddata->clk)) {
340		ret = PTR_ERR(ddata->clk);
341		dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
342		goto err;
343	}
344
345	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
346	if (!res) {
347		ret = -ENODEV;
348		dev_err(&pdev->dev, "failed to determine base address\n");
349		goto err;
350	}
351
352	if (resource_size(res) < 0x60) {
353		ret = -EINVAL;
354		dev_err(&pdev->dev, "memory resource too small\n");
355		goto err;
356	}
357
358	ddata->base = devm_ioremap_resource(&pdev->dev, res);
359	if (IS_ERR(ddata->base)) {
360		ret = PTR_ERR(ddata->base);
361		goto err;
362	}
363
364	ret = platform_get_irq(pdev, 0);
365	if (ret <= 0)
366		goto err;
367
368	ddata->rxirq = ret;
369
370	ret = platform_get_irq(pdev, 1);
371	if (ret <= 0)
372		ret = ddata->rxirq + 1;
373
374	ddata->txirq = ret;
375
376	ret = clk_prepare_enable(ddata->clk);
377	if (ret < 0) {
378		dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
379		goto err;
380	}
381
382	efm32_spi_probe_dt(pdev, master, ddata);
383
384	efm32_spi_write32(ddata, 0, REG_IEN);
385	efm32_spi_write32(ddata, REG_ROUTE_TXPEN | REG_ROUTE_RXPEN |
386			REG_ROUTE_CLKPEN |
387			REG_ROUTE_LOCATION(ddata->pdata.location), REG_ROUTE);
388
389	ret = request_irq(ddata->rxirq, efm32_spi_rxirq,
390			0, DRIVER_NAME " rx", ddata);
391	if (ret) {
392		dev_err(&pdev->dev, "failed to register rxirq (%d)\n", ret);
393		goto err_disable_clk;
394	}
395
396	ret = request_irq(ddata->txirq, efm32_spi_txirq,
397			0, DRIVER_NAME " tx", ddata);
398	if (ret) {
399		dev_err(&pdev->dev, "failed to register txirq (%d)\n", ret);
400		goto err_free_rx_irq;
401	}
402
403	ret = spi_bitbang_start(&ddata->bitbang);
404	if (ret) {
405		dev_err(&pdev->dev, "spi_bitbang_start failed (%d)\n", ret);
406
407		free_irq(ddata->txirq, ddata);
408err_free_rx_irq:
409		free_irq(ddata->rxirq, ddata);
410err_disable_clk:
411		clk_disable_unprepare(ddata->clk);
412err:
413		spi_master_put(master);
414	}
415
416	return ret;
417}
418
419static int efm32_spi_remove(struct platform_device *pdev)
420{
421	struct spi_master *master = platform_get_drvdata(pdev);
422	struct efm32_spi_ddata *ddata = spi_master_get_devdata(master);
423
424	spi_bitbang_stop(&ddata->bitbang);
425
426	efm32_spi_write32(ddata, 0, REG_IEN);
427
428	free_irq(ddata->txirq, ddata);
429	free_irq(ddata->rxirq, ddata);
430	clk_disable_unprepare(ddata->clk);
431	spi_master_put(master);
432
433	return 0;
434}
435
436static const struct of_device_id efm32_spi_dt_ids[] = {
437	{
438		.compatible = "energymicro,efm32-spi",
439	}, {
440		/* doesn't follow the "vendor,device" scheme, don't use */
441		.compatible = "efm32,spi",
442	}, {
443		/* sentinel */
444	}
445};
446MODULE_DEVICE_TABLE(of, efm32_spi_dt_ids);
447
448static struct platform_driver efm32_spi_driver = {
449	.probe = efm32_spi_probe,
450	.remove = efm32_spi_remove,
451
452	.driver = {
453		.name = DRIVER_NAME,
454		.of_match_table = efm32_spi_dt_ids,
455	},
456};
457module_platform_driver(efm32_spi_driver);
458
459MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
460MODULE_DESCRIPTION("EFM32 SPI driver");
461MODULE_LICENSE("GPL v2");
462MODULE_ALIAS("platform:" DRIVER_NAME);
463