1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * MPC52xx PSC in SPI mode driver.
4 *
5 * Maintainer: Dragos Carp
6 *
7 * Copyright (C) 2006 TOPTICA Photonics AG.
8 */
9
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <linux/errno.h>
13 #include <linux/interrupt.h>
14 #include <linux/platform_device.h>
15 #include <linux/property.h>
16 #include <linux/workqueue.h>
17 #include <linux/completion.h>
18 #include <linux/io.h>
19 #include <linux/delay.h>
20 #include <linux/spi/spi.h>
21 #include <linux/slab.h>
22
23 #include <asm/mpc52xx.h>
24 #include <asm/mpc52xx_psc.h>
25
26 #define MCLK 20000000 /* PSC port MClk in hz */
27
28 struct mpc52xx_psc_spi {
29 /* driver internal data */
30 struct mpc52xx_psc __iomem *psc;
31 struct mpc52xx_psc_fifo __iomem *fifo;
32 int irq;
33 u8 bits_per_word;
34
35 struct completion done;
36 };
37
38 /* controller state */
39 struct mpc52xx_psc_spi_cs {
40 int bits_per_word;
41 int speed_hz;
42 };
43
44 /* set clock freq, clock ramp, bits per work
45 * if t is NULL then reset the values to the default values
46 */
mpc52xx_psc_spi_transfer_setup(struct spi_device * spi,struct spi_transfer * t)47 static int mpc52xx_psc_spi_transfer_setup(struct spi_device *spi,
48 struct spi_transfer *t)
49 {
50 struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
51
52 cs->speed_hz = (t && t->speed_hz)
53 ? t->speed_hz : spi->max_speed_hz;
54 cs->bits_per_word = (t && t->bits_per_word)
55 ? t->bits_per_word : spi->bits_per_word;
56 cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
57 return 0;
58 }
59
mpc52xx_psc_spi_activate_cs(struct spi_device * spi)60 static void mpc52xx_psc_spi_activate_cs(struct spi_device *spi)
61 {
62 struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
63 struct mpc52xx_psc_spi *mps = spi_controller_get_devdata(spi->controller);
64 struct mpc52xx_psc __iomem *psc = mps->psc;
65 u32 sicr;
66 u16 ccr;
67
68 sicr = in_be32(&psc->sicr);
69
70 /* Set clock phase and polarity */
71 if (spi->mode & SPI_CPHA)
72 sicr |= 0x00001000;
73 else
74 sicr &= ~0x00001000;
75 if (spi->mode & SPI_CPOL)
76 sicr |= 0x00002000;
77 else
78 sicr &= ~0x00002000;
79
80 if (spi->mode & SPI_LSB_FIRST)
81 sicr |= 0x10000000;
82 else
83 sicr &= ~0x10000000;
84 out_be32(&psc->sicr, sicr);
85
86 /* Set clock frequency and bits per word
87 * Because psc->ccr is defined as 16bit register instead of 32bit
88 * just set the lower byte of BitClkDiv
89 */
90 ccr = in_be16((u16 __iomem *)&psc->ccr);
91 ccr &= 0xFF00;
92 if (cs->speed_hz)
93 ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
94 else /* by default SPI Clk 1MHz */
95 ccr |= (MCLK / 1000000 - 1) & 0xFF;
96 out_be16((u16 __iomem *)&psc->ccr, ccr);
97 mps->bits_per_word = cs->bits_per_word;
98 }
99
100 #define MPC52xx_PSC_BUFSIZE (MPC52xx_PSC_RFNUM_MASK + 1)
101 /* wake up when 80% fifo full */
102 #define MPC52xx_PSC_RFALARM (MPC52xx_PSC_BUFSIZE * 20 / 100)
103
mpc52xx_psc_spi_transfer_rxtx(struct spi_device * spi,struct spi_transfer * t)104 static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
105 struct spi_transfer *t)
106 {
107 struct mpc52xx_psc_spi *mps = spi_controller_get_devdata(spi->controller);
108 struct mpc52xx_psc __iomem *psc = mps->psc;
109 struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
110 unsigned rb = 0; /* number of bytes receieved */
111 unsigned sb = 0; /* number of bytes sent */
112 unsigned char *rx_buf = (unsigned char *)t->rx_buf;
113 unsigned char *tx_buf = (unsigned char *)t->tx_buf;
114 unsigned rfalarm;
115 unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
116 unsigned recv_at_once;
117 int last_block = 0;
118
119 if (!t->tx_buf && !t->rx_buf && t->len)
120 return -EINVAL;
121
122 /* enable transmiter/receiver */
123 out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
124 while (rb < t->len) {
125 if (t->len - rb > MPC52xx_PSC_BUFSIZE) {
126 rfalarm = MPC52xx_PSC_RFALARM;
127 last_block = 0;
128 } else {
129 send_at_once = t->len - sb;
130 rfalarm = MPC52xx_PSC_BUFSIZE - (t->len - rb);
131 last_block = 1;
132 }
133
134 dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
135 for (; send_at_once; sb++, send_at_once--) {
136 /* set EOF flag before the last word is sent */
137 if (send_at_once == 1 && last_block)
138 out_8(&psc->ircr2, 0x01);
139
140 if (tx_buf)
141 out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
142 else
143 out_8(&psc->mpc52xx_psc_buffer_8, 0);
144 }
145
146
147 /* enable interrupts and wait for wake up
148 * if just one byte is expected the Rx FIFO genererates no
149 * FFULL interrupt, so activate the RxRDY interrupt
150 */
151 out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
152 if (t->len - rb == 1) {
153 out_8(&psc->mode, 0);
154 } else {
155 out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
156 out_be16(&fifo->rfalarm, rfalarm);
157 }
158 out_be16(&psc->mpc52xx_psc_imr, MPC52xx_PSC_IMR_RXRDY);
159 wait_for_completion(&mps->done);
160 recv_at_once = in_be16(&fifo->rfnum);
161 dev_dbg(&spi->dev, "%d bytes received\n", recv_at_once);
162
163 send_at_once = recv_at_once;
164 if (rx_buf) {
165 for (; recv_at_once; rb++, recv_at_once--)
166 rx_buf[rb] = in_8(&psc->mpc52xx_psc_buffer_8);
167 } else {
168 for (; recv_at_once; rb++, recv_at_once--)
169 in_8(&psc->mpc52xx_psc_buffer_8);
170 }
171 }
172 /* disable transmiter/receiver */
173 out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
174
175 return 0;
176 }
177
mpc52xx_psc_spi_transfer_one_message(struct spi_controller * ctlr,struct spi_message * m)178 static int mpc52xx_psc_spi_transfer_one_message(struct spi_controller *ctlr,
179 struct spi_message *m)
180 {
181 struct spi_device *spi;
182 struct spi_transfer *t = NULL;
183 unsigned cs_change;
184 int status;
185
186 spi = m->spi;
187 cs_change = 1;
188 status = 0;
189 list_for_each_entry (t, &m->transfers, transfer_list) {
190 if (t->bits_per_word || t->speed_hz) {
191 status = mpc52xx_psc_spi_transfer_setup(spi, t);
192 if (status < 0)
193 break;
194 }
195
196 if (cs_change)
197 mpc52xx_psc_spi_activate_cs(spi);
198 cs_change = t->cs_change;
199
200 status = mpc52xx_psc_spi_transfer_rxtx(spi, t);
201 if (status)
202 break;
203 m->actual_length += t->len;
204
205 spi_transfer_delay_exec(t);
206 }
207
208 m->status = status;
209
210 mpc52xx_psc_spi_transfer_setup(spi, NULL);
211
212 spi_finalize_current_message(ctlr);
213
214 return 0;
215 }
216
mpc52xx_psc_spi_setup(struct spi_device * spi)217 static int mpc52xx_psc_spi_setup(struct spi_device *spi)
218 {
219 struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
220
221 if (spi->bits_per_word%8)
222 return -EINVAL;
223
224 if (!cs) {
225 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
226 if (!cs)
227 return -ENOMEM;
228 spi->controller_state = cs;
229 }
230
231 cs->bits_per_word = spi->bits_per_word;
232 cs->speed_hz = spi->max_speed_hz;
233
234 return 0;
235 }
236
mpc52xx_psc_spi_cleanup(struct spi_device * spi)237 static void mpc52xx_psc_spi_cleanup(struct spi_device *spi)
238 {
239 kfree(spi->controller_state);
240 }
241
mpc52xx_psc_spi_port_config(int psc_id,struct mpc52xx_psc_spi * mps)242 static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)
243 {
244 struct mpc52xx_psc __iomem *psc = mps->psc;
245 struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
246 u32 mclken_div;
247 int ret;
248
249 /* default sysclk is 512MHz */
250 mclken_div = 512000000 / MCLK;
251 ret = mpc52xx_set_psc_clkdiv(psc_id, mclken_div);
252 if (ret)
253 return ret;
254
255 /* Reset the PSC into a known state */
256 out_8(&psc->command, MPC52xx_PSC_RST_RX);
257 out_8(&psc->command, MPC52xx_PSC_RST_TX);
258 out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
259
260 /* Disable interrupts, interrupts are based on alarm level */
261 out_be16(&psc->mpc52xx_psc_imr, 0);
262 out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
263 out_8(&fifo->rfcntl, 0);
264 out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
265
266 /* Configure 8bit codec mode as a SPI host and use EOF flags */
267 /* SICR_SIM_CODEC8|SICR_GENCLK|SICR_SPI|SICR_MSTR|SICR_USEEOF */
268 out_be32(&psc->sicr, 0x0180C800);
269 out_be16((u16 __iomem *)&psc->ccr, 0x070F); /* default SPI Clk 1MHz */
270
271 /* Set 2ms DTL delay */
272 out_8(&psc->ctur, 0x00);
273 out_8(&psc->ctlr, 0x84);
274
275 mps->bits_per_word = 8;
276
277 return 0;
278 }
279
mpc52xx_psc_spi_isr(int irq,void * dev_id)280 static irqreturn_t mpc52xx_psc_spi_isr(int irq, void *dev_id)
281 {
282 struct mpc52xx_psc_spi *mps = (struct mpc52xx_psc_spi *)dev_id;
283 struct mpc52xx_psc __iomem *psc = mps->psc;
284
285 /* disable interrupt and wake up the work queue */
286 if (in_be16(&psc->mpc52xx_psc_isr) & MPC52xx_PSC_IMR_RXRDY) {
287 out_be16(&psc->mpc52xx_psc_imr, 0);
288 complete(&mps->done);
289 return IRQ_HANDLED;
290 }
291 return IRQ_NONE;
292 }
293
mpc52xx_psc_spi_of_probe(struct platform_device * pdev)294 static int mpc52xx_psc_spi_of_probe(struct platform_device *pdev)
295 {
296 struct device *dev = &pdev->dev;
297 struct mpc52xx_psc_spi *mps;
298 struct spi_controller *host;
299 u32 bus_num;
300 int ret;
301
302 host = devm_spi_alloc_host(dev, sizeof(*mps));
303 if (host == NULL)
304 return -ENOMEM;
305
306 dev_set_drvdata(dev, host);
307 mps = spi_controller_get_devdata(host);
308
309 /* the spi->mode bits understood by this driver: */
310 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
311
312 ret = device_property_read_u32(dev, "cell-index", &bus_num);
313 if (ret || bus_num > 5)
314 return dev_err_probe(dev, ret ? : -EINVAL, "Invalid cell-index property\n");
315 host->bus_num = bus_num + 1;
316
317 host->num_chipselect = 255;
318 host->setup = mpc52xx_psc_spi_setup;
319 host->transfer_one_message = mpc52xx_psc_spi_transfer_one_message;
320 host->cleanup = mpc52xx_psc_spi_cleanup;
321
322 device_set_node(&host->dev, dev_fwnode(dev));
323
324 mps->psc = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
325 if (IS_ERR(mps->psc))
326 return dev_err_probe(dev, PTR_ERR(mps->psc), "could not ioremap I/O port range\n");
327
328 /* On the 5200, fifo regs are immediately ajacent to the psc regs */
329 mps->fifo = ((void __iomem *)mps->psc) + sizeof(struct mpc52xx_psc);
330
331 mps->irq = platform_get_irq(pdev, 0);
332 if (mps->irq < 0)
333 return mps->irq;
334
335 ret = devm_request_irq(dev, mps->irq, mpc52xx_psc_spi_isr, 0,
336 "mpc52xx-psc-spi", mps);
337 if (ret)
338 return ret;
339
340 ret = mpc52xx_psc_spi_port_config(host->bus_num, mps);
341 if (ret < 0)
342 return dev_err_probe(dev, ret, "can't configure PSC! Is it capable of SPI?\n");
343
344 init_completion(&mps->done);
345
346 return devm_spi_register_controller(dev, host);
347 }
348
349 static const struct of_device_id mpc52xx_psc_spi_of_match[] = {
350 { .compatible = "fsl,mpc5200-psc-spi", },
351 { .compatible = "mpc5200-psc-spi", }, /* old */
352 {}
353 };
354
355 MODULE_DEVICE_TABLE(of, mpc52xx_psc_spi_of_match);
356
357 static struct platform_driver mpc52xx_psc_spi_of_driver = {
358 .probe = mpc52xx_psc_spi_of_probe,
359 .driver = {
360 .name = "mpc52xx-psc-spi",
361 .of_match_table = mpc52xx_psc_spi_of_match,
362 },
363 };
364 module_platform_driver(mpc52xx_psc_spi_of_driver);
365
366 MODULE_AUTHOR("Dragos Carp");
367 MODULE_DESCRIPTION("MPC52xx PSC SPI Driver");
368 MODULE_LICENSE("GPL");
369