1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2015 Marvell International Ltd.
4 *
5 * Copyright (C) 2016 Stefan Roese <sr@denx.de>
6 */
7
8 #include <common.h>
9 #include <dm.h>
10 #include <log.h>
11 #include <malloc.h>
12 #include <spi.h>
13 #include <clk.h>
14 #include <wait_bit.h>
15 #include <asm/global_data.h>
16 #include <asm/io.h>
17 #include <dm/device_compat.h>
18 #include <linux/bitops.h>
19 #include <asm/gpio.h>
20
21 DECLARE_GLOBAL_DATA_PTR;
22
23 #define MVEBU_SPI_A3700_XFER_RDY BIT(1)
24 #define MVEBU_SPI_A3700_FIFO_FLUSH BIT(9)
25 #define MVEBU_SPI_A3700_BYTE_LEN BIT(5)
26 #define MVEBU_SPI_A3700_CLK_PHA BIT(6)
27 #define MVEBU_SPI_A3700_CLK_POL BIT(7)
28 #define MVEBU_SPI_A3700_FIFO_EN BIT(17)
29 #define MVEBU_SPI_A3700_SPI_EN_0 BIT(16)
30 #define MVEBU_SPI_A3700_CLK_PRESCALE_MASK 0x1f
31
32 #define MAX_CS_COUNT 4
33
34 /* SPI registers */
35 struct spi_reg {
36 u32 ctrl; /* 0x10600 */
37 u32 cfg; /* 0x10604 */
38 u32 dout; /* 0x10608 */
39 u32 din; /* 0x1060c */
40 };
41
42 struct mvebu_spi_plat {
43 struct spi_reg *spireg;
44 struct clk clk;
45 struct gpio_desc cs_gpios[MAX_CS_COUNT];
46 };
47
spi_cs_activate(struct mvebu_spi_plat * plat,int cs)48 static void spi_cs_activate(struct mvebu_spi_plat *plat, int cs)
49 {
50 if (CONFIG_IS_ENABLED(DM_GPIO) && dm_gpio_is_valid(&plat->cs_gpios[cs]))
51 dm_gpio_set_value(&plat->cs_gpios[cs], 1);
52 else
53 setbits_le32(&plat->spireg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
54 }
55
spi_cs_deactivate(struct mvebu_spi_plat * plat,int cs)56 static void spi_cs_deactivate(struct mvebu_spi_plat *plat, int cs)
57 {
58 if (CONFIG_IS_ENABLED(DM_GPIO) && dm_gpio_is_valid(&plat->cs_gpios[cs]))
59 dm_gpio_set_value(&plat->cs_gpios[cs], 0);
60 else
61 clrbits_le32(&plat->spireg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
62 }
63
64 /**
65 * spi_legacy_shift_byte() - triggers the real SPI transfer
66 * @bytelen: Indicate how many bytes to transfer.
67 * @dout: Buffer address of what to send.
68 * @din: Buffer address of where to receive.
69 *
70 * This function triggers the real SPI transfer in legacy mode. It
71 * will shift out char buffer from @dout, and shift in char buffer to
72 * @din, if necessary.
73 *
74 * This function assumes that only one byte is shifted at one time.
75 * However, it is not its responisbility to set the transfer type to
76 * one-byte. Also, it does not guarantee that it will work if transfer
77 * type becomes two-byte. See spi_set_legacy() for details.
78 *
79 * In legacy mode, simply write to the SPI_DOUT register will trigger
80 * the transfer.
81 *
82 * If @dout == NULL, which means no actual data needs to be sent out,
83 * then the function will shift out 0x00 in order to shift in data.
84 * The XFER_RDY flag is checked every time before accessing SPI_DOUT
85 * and SPI_DIN register.
86 *
87 * The number of transfers to be triggerred is decided by @bytelen.
88 *
89 * Return: 0 - cool
90 * -ETIMEDOUT - XFER_RDY flag timeout
91 */
spi_legacy_shift_byte(struct spi_reg * reg,unsigned int bytelen,const void * dout,void * din)92 static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
93 const void *dout, void *din)
94 {
95 const u8 *dout_8;
96 u8 *din_8;
97 int ret;
98
99 /* Use 0x00 as dummy dout */
100 const u8 dummy_dout = 0x0;
101 u32 pending_dout = 0x0;
102
103 /* dout_8: pointer of current dout */
104 dout_8 = dout;
105 /* din_8: pointer of current din */
106 din_8 = din;
107
108 while (bytelen) {
109 ret = wait_for_bit_le32(®->ctrl,
110 MVEBU_SPI_A3700_XFER_RDY,
111 true,100, false);
112 if (ret)
113 return ret;
114
115 if (dout)
116 pending_dout = (u32)*dout_8;
117 else
118 pending_dout = (u32)dummy_dout;
119
120 /* Trigger the xfer */
121 writel(pending_dout, ®->dout);
122
123 if (din) {
124 ret = wait_for_bit_le32(®->ctrl,
125 MVEBU_SPI_A3700_XFER_RDY,
126 true, 100, false);
127 if (ret)
128 return ret;
129
130 /* Read what is transferred in */
131 *din_8 = (u8)readl(®->din);
132 }
133
134 /* Don't increment the current pointer if NULL */
135 if (dout)
136 dout_8++;
137 if (din)
138 din_8++;
139
140 bytelen--;
141 }
142
143 return 0;
144 }
145
mvebu_spi_xfer(struct udevice * dev,unsigned int bitlen,const void * dout,void * din,unsigned long flags)146 static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
147 const void *dout, void *din, unsigned long flags)
148 {
149 struct udevice *bus = dev->parent;
150 struct mvebu_spi_plat *plat = dev_get_plat(bus);
151 struct spi_reg *reg = plat->spireg;
152 unsigned int bytelen;
153 int ret;
154
155 bytelen = bitlen / 8;
156
157 if (dout && din)
158 debug("This is a duplex transfer.\n");
159
160 /* Activate CS */
161 if (flags & SPI_XFER_BEGIN) {
162 debug("SPI: activate cs.\n");
163 spi_cs_activate(plat, spi_chip_select(dev));
164 }
165
166 /* Send and/or receive */
167 if (dout || din) {
168 ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
169 if (ret)
170 return ret;
171 }
172
173 /* Deactivate CS */
174 if (flags & SPI_XFER_END) {
175 ret = wait_for_bit_le32(®->ctrl,
176 MVEBU_SPI_A3700_XFER_RDY,
177 true, 100, false);
178 if (ret)
179 return ret;
180
181 debug("SPI: deactivate cs.\n");
182 spi_cs_deactivate(plat, spi_chip_select(dev));
183 }
184
185 return 0;
186 }
187
mvebu_spi_set_speed(struct udevice * bus,uint hz)188 static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
189 {
190 struct mvebu_spi_plat *plat = dev_get_plat(bus);
191 struct spi_reg *reg = plat->spireg;
192 u32 data, prescale;
193
194 data = readl(®->cfg);
195
196 prescale = DIV_ROUND_UP(clk_get_rate(&plat->clk), hz);
197 if (prescale > 0xf)
198 prescale = 0x10 + (prescale + 1) / 2;
199 prescale = min(prescale, 0x1fu);
200
201 data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
202 data |= prescale & MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
203
204 writel(data, ®->cfg);
205
206 return 0;
207 }
208
mvebu_spi_set_mode(struct udevice * bus,uint mode)209 static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
210 {
211 struct mvebu_spi_plat *plat = dev_get_plat(bus);
212 struct spi_reg *reg = plat->spireg;
213
214 /*
215 * Set SPI polarity
216 * 0: Serial interface clock is low when inactive
217 * 1: Serial interface clock is high when inactive
218 */
219 if (mode & SPI_CPOL)
220 setbits_le32(®->cfg, MVEBU_SPI_A3700_CLK_POL);
221 else
222 clrbits_le32(®->cfg, MVEBU_SPI_A3700_CLK_POL);
223 if (mode & SPI_CPHA)
224 setbits_le32(®->cfg, MVEBU_SPI_A3700_CLK_PHA);
225 else
226 clrbits_le32(®->cfg, MVEBU_SPI_A3700_CLK_PHA);
227
228 return 0;
229 }
230
mvebu_spi_probe(struct udevice * bus)231 static int mvebu_spi_probe(struct udevice *bus)
232 {
233 struct mvebu_spi_plat *plat = dev_get_plat(bus);
234 struct spi_reg *reg = plat->spireg;
235 u32 data;
236 int ret;
237
238 /*
239 * Settings SPI controller to be working in legacy mode, which
240 * means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
241 * for Data In.
242 */
243
244 /* Flush read/write FIFO */
245 data = readl(®->cfg);
246 writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, ®->cfg);
247 ret = wait_for_bit_le32(®->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
248 false, 1000, false);
249 if (ret)
250 return ret;
251
252 /* Disable FIFO mode */
253 data &= ~MVEBU_SPI_A3700_FIFO_EN;
254
255 /* Always shift 1 byte at a time */
256 data &= ~MVEBU_SPI_A3700_BYTE_LEN;
257
258 writel(data, ®->cfg);
259
260 /* Set up CS GPIOs in device tree, if any */
261 if (CONFIG_IS_ENABLED(DM_GPIO) && gpio_get_list_count(bus, "cs-gpios") > 0) {
262 int i;
263
264 for (i = 0; i < ARRAY_SIZE(plat->cs_gpios); i++) {
265 ret = gpio_request_by_name(bus, "cs-gpios", i, &plat->cs_gpios[i], 0);
266 if (ret < 0 || !dm_gpio_is_valid(&plat->cs_gpios[i])) {
267 /* Use the native CS function for this line */
268 continue;
269 }
270
271 ret = dm_gpio_set_dir_flags(&plat->cs_gpios[i],
272 GPIOD_IS_OUT | GPIOD_ACTIVE_LOW);
273 if (ret) {
274 dev_err(bus, "Setting cs %d error\n", i);
275 return ret;
276 }
277 }
278 }
279
280 return 0;
281 }
282
mvebu_spi_of_to_plat(struct udevice * bus)283 static int mvebu_spi_of_to_plat(struct udevice *bus)
284 {
285 struct mvebu_spi_plat *plat = dev_get_plat(bus);
286 int ret;
287
288 plat->spireg = dev_read_addr_ptr(bus);
289
290 ret = clk_get_by_index(bus, 0, &plat->clk);
291 if (ret) {
292 dev_err(bus, "cannot get clock\n");
293 return ret;
294 }
295
296 return 0;
297 }
298
mvebu_spi_remove(struct udevice * bus)299 static int mvebu_spi_remove(struct udevice *bus)
300 {
301 struct mvebu_spi_plat *plat = dev_get_plat(bus);
302
303 clk_free(&plat->clk);
304
305 return 0;
306 }
307
308 static const struct dm_spi_ops mvebu_spi_ops = {
309 .xfer = mvebu_spi_xfer,
310 .set_speed = mvebu_spi_set_speed,
311 .set_mode = mvebu_spi_set_mode,
312 /*
313 * cs_info is not needed, since we require all chip selects to be
314 * in the device tree explicitly
315 */
316 };
317
318 static const struct udevice_id mvebu_spi_ids[] = {
319 { .compatible = "marvell,armada-3700-spi" },
320 { }
321 };
322
323 U_BOOT_DRIVER(mvebu_spi) = {
324 .name = "mvebu_spi",
325 .id = UCLASS_SPI,
326 .of_match = mvebu_spi_ids,
327 .ops = &mvebu_spi_ops,
328 .of_to_plat = mvebu_spi_of_to_plat,
329 .plat_auto = sizeof(struct mvebu_spi_plat),
330 .probe = mvebu_spi_probe,
331 .remove = mvebu_spi_remove,
332 };
333