1 // SPDX-License-Identifier: GPL-2.0+
4 * Copyright (C) 2008 Christian Pellegrin <chripell@evolware.org>
6 * Notes: the MAX3100 doesn't provide an interrupt on CTS so we have
7 * to use polling for flow control. TX empty IRQ is unusable, since
8 * writing conf clears FIFO buffer and we cannot have this interrupt
9 * always asking us for attention.
11 * Example platform data:
13 static struct plat_max3100 max3100_plat_data = {
19 static struct spi_board_info spi_board_info[] = {
21 .modalias = "max3100",
22 .platform_data = &max3100_plat_data,
24 .max_speed_hz = 5*1000*1000,
29 * The initial minor number is 209 in the low-density serial port:
30 * mknod /dev/ttyMAX0 c 204 209
33 #define MAX3100_MAJOR 204
34 #define MAX3100_MINOR 209
35 /* 4 MAX3100s should be enough for everyone */
38 #include <linux/delay.h>
39 #include <linux/slab.h>
40 #include <linux/device.h>
41 #include <linux/module.h>
42 #include <linux/serial_core.h>
43 #include <linux/serial.h>
44 #include <linux/spi/spi.h>
45 #include <linux/freezer.h>
46 #include <linux/tty.h>
47 #include <linux/tty_flip.h>
48 #include <linux/types.h>
50 #include <asm/unaligned.h>
52 #include <linux/serial_max3100.h>
54 #define MAX3100_C (1<<14)
55 #define MAX3100_D (0<<14)
56 #define MAX3100_W (1<<15)
57 #define MAX3100_RX (0<<15)
59 #define MAX3100_WC (MAX3100_W | MAX3100_C)
60 #define MAX3100_RC (MAX3100_RX | MAX3100_C)
61 #define MAX3100_WD (MAX3100_W | MAX3100_D)
62 #define MAX3100_RD (MAX3100_RX | MAX3100_D)
63 #define MAX3100_CMD (3 << 14)
65 #define MAX3100_T (1<<14)
66 #define MAX3100_R (1<<15)
68 #define MAX3100_FEN (1<<13)
69 #define MAX3100_SHDN (1<<12)
70 #define MAX3100_TM (1<<11)
71 #define MAX3100_RM (1<<10)
72 #define MAX3100_PM (1<<9)
73 #define MAX3100_RAM (1<<8)
74 #define MAX3100_IR (1<<7)
75 #define MAX3100_ST (1<<6)
76 #define MAX3100_PE (1<<5)
77 #define MAX3100_L (1<<4)
78 #define MAX3100_BAUD (0xf)
80 #define MAX3100_TE (1<<10)
81 #define MAX3100_RAFE (1<<10)
82 #define MAX3100_RTS (1<<9)
83 #define MAX3100_CTS (1<<9)
84 #define MAX3100_PT (1<<8)
85 #define MAX3100_DATA (0xff)
87 #define MAX3100_RT (MAX3100_R | MAX3100_T)
88 #define MAX3100_RTC (MAX3100_RT | MAX3100_CTS | MAX3100_RAFE)
90 /* the following simulate a status reg for ignore_status_mask */
91 #define MAX3100_STATUS_PE 1
92 #define MAX3100_STATUS_FE 2
93 #define MAX3100_STATUS_OE 4
96 struct uart_port port;
97 struct spi_device *spi;
99 int cts; /* last CTS received for flow ctrl */
100 int tx_empty; /* last TX empty bit */
102 spinlock_t conf_lock; /* shared data */
103 int conf_commit; /* need to make changes */
104 int conf; /* configuration for the MAX31000
105 * (bits 0-7, bits 8-11 are irqs) */
106 int rts_commit; /* need to change rts */
107 int rts; /* rts status */
108 int baud; /* current baud rate */
110 int parity; /* keeps track if we should send parity */
111 #define MAX3100_PARITY_ON 1
112 #define MAX3100_PARITY_ODD 2
113 #define MAX3100_7BIT 4
114 int rx_enabled; /* if we should rx chars */
116 int irq; /* irq assigned to the max3100 */
118 int minor; /* minor number */
119 int crystal; /* 1 if 3.6864Mhz crystal 0 for 1.8432 */
120 int loopback; /* 1 if we are in loopback mode */
122 /* for handling irqs: need workqueue since we do spi_sync */
123 struct workqueue_struct *workqueue;
124 struct work_struct work;
125 /* set to 1 to make the workhandler exit as soon as possible */
127 /* need to know we are suspending to avoid deadlock on workqueue */
130 /* hook for suspending MAX3100 via dedicated pin */
131 void (*max3100_hw_suspend) (int suspend);
133 /* poll time (in ms) for ctrl lines */
136 struct timer_list timer;
139 static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
140 static DEFINE_MUTEX(max3100s_lock); /* race on probe */
142 static int max3100_do_parity(struct max3100_port *s, u16 c)
146 if (s->parity & MAX3100_PARITY_ODD)
151 if (s->parity & MAX3100_7BIT)
156 parity = parity ^ (hweight8(c) & 1);
160 static int max3100_check_parity(struct max3100_port *s, u16 c)
162 return max3100_do_parity(s, c) == ((c >> 8) & 1);
165 static void max3100_calc_parity(struct max3100_port *s, u16 *c)
167 if (s->parity & MAX3100_7BIT)
172 if (s->parity & MAX3100_PARITY_ON)
173 *c |= max3100_do_parity(s, *c) << 8;
176 static void max3100_work(struct work_struct *w);
178 static void max3100_dowork(struct max3100_port *s)
180 if (!s->force_end_work && !freezing(current) && !s->suspending)
181 queue_work(s->workqueue, &s->work);
184 static void max3100_timeout(struct timer_list *t)
186 struct max3100_port *s = from_timer(s, t, timer);
190 mod_timer(&s->timer, jiffies + s->poll_time);
194 static int max3100_sr(struct max3100_port *s, u16 tx, u16 *rx)
196 struct spi_message message;
199 struct spi_transfer tran = {
205 etx = cpu_to_be16(tx);
206 spi_message_init(&message);
207 spi_message_add_tail(&tran, &message);
208 status = spi_sync(s->spi, &message);
210 dev_warn(&s->spi->dev, "error while calling spi_sync\n");
213 *rx = be16_to_cpu(erx);
214 s->tx_empty = (*rx & MAX3100_T) > 0;
215 dev_dbg(&s->spi->dev, "%04x - %04x\n", tx, *rx);
219 static int max3100_handlerx_unlocked(struct max3100_port *s, u16 rx)
221 unsigned int ch, flg, status = 0;
224 if (rx & MAX3100_R && s->rx_enabled) {
225 dev_dbg(&s->spi->dev, "%s\n", __func__);
226 ch = rx & (s->parity & MAX3100_7BIT ? 0x7f : 0xff);
227 if (rx & MAX3100_RAFE) {
228 s->port.icount.frame++;
230 status |= MAX3100_STATUS_FE;
232 if (s->parity & MAX3100_PARITY_ON) {
233 if (max3100_check_parity(s, rx)) {
237 s->port.icount.parity++;
239 status |= MAX3100_STATUS_PE;
246 uart_insert_char(&s->port, status, MAX3100_STATUS_OE, ch, flg);
250 cts = (rx & MAX3100_CTS) > 0;
253 uart_handle_cts_change(&s->port, cts ? TIOCM_CTS : 0);
259 static int max3100_handlerx(struct max3100_port *s, u16 rx)
264 uart_port_lock_irqsave(&s->port, &flags);
265 ret = max3100_handlerx_unlocked(s, rx);
266 uart_port_unlock_irqrestore(&s->port, flags);
270 static void max3100_work(struct work_struct *w)
272 struct max3100_port *s = container_of(w, struct max3100_port, work);
275 int conf, cconf, crts;
276 struct circ_buf *xmit = &s->port.state->xmit;
278 dev_dbg(&s->spi->dev, "%s\n", __func__);
282 spin_lock(&s->conf_lock);
284 cconf = s->conf_commit;
286 crts = s->rts_commit;
288 spin_unlock(&s->conf_lock);
290 max3100_sr(s, MAX3100_WC | conf, &rx);
292 max3100_sr(s, MAX3100_WD | MAX3100_TE |
293 (s->rts ? MAX3100_RTS : 0), &rx);
294 rxchars += max3100_handlerx(s, rx);
297 max3100_sr(s, MAX3100_RD, &rx);
298 rxchars += max3100_handlerx(s, rx);
300 if (rx & MAX3100_T) {
302 if (s->port.x_char) {
306 } else if (!uart_circ_empty(xmit) &&
307 !uart_tx_stopped(&s->port)) {
308 tx = xmit->buf[xmit->tail];
309 xmit->tail = (xmit->tail + 1) &
310 (UART_XMIT_SIZE - 1);
314 max3100_calc_parity(s, &tx);
315 tx |= MAX3100_WD | (s->rts ? MAX3100_RTS : 0);
316 max3100_sr(s, tx, &rx);
317 rxchars += max3100_handlerx(s, rx);
322 tty_flip_buffer_push(&s->port.state->port);
325 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
326 uart_write_wakeup(&s->port);
328 } while (!s->force_end_work &&
329 !freezing(current) &&
331 (!uart_circ_empty(xmit) &&
332 !uart_tx_stopped(&s->port))));
335 tty_flip_buffer_push(&s->port.state->port);
338 static irqreturn_t max3100_irq(int irqno, void *dev_id)
340 struct max3100_port *s = dev_id;
342 dev_dbg(&s->spi->dev, "%s\n", __func__);
348 static void max3100_enable_ms(struct uart_port *port)
350 struct max3100_port *s = container_of(port,
354 if (s->poll_time > 0)
355 mod_timer(&s->timer, jiffies);
356 dev_dbg(&s->spi->dev, "%s\n", __func__);
359 static void max3100_start_tx(struct uart_port *port)
361 struct max3100_port *s = container_of(port,
365 dev_dbg(&s->spi->dev, "%s\n", __func__);
370 static void max3100_stop_rx(struct uart_port *port)
372 struct max3100_port *s = container_of(port,
376 dev_dbg(&s->spi->dev, "%s\n", __func__);
379 spin_lock(&s->conf_lock);
380 s->conf &= ~MAX3100_RM;
382 spin_unlock(&s->conf_lock);
386 static unsigned int max3100_tx_empty(struct uart_port *port)
388 struct max3100_port *s = container_of(port,
392 dev_dbg(&s->spi->dev, "%s\n", __func__);
394 /* may not be truly up-to-date */
399 static unsigned int max3100_get_mctrl(struct uart_port *port)
401 struct max3100_port *s = container_of(port,
405 dev_dbg(&s->spi->dev, "%s\n", __func__);
407 /* may not be truly up-to-date */
409 /* always assert DCD and DSR since these lines are not wired */
410 return (s->cts ? TIOCM_CTS : 0) | TIOCM_DSR | TIOCM_CAR;
413 static void max3100_set_mctrl(struct uart_port *port, unsigned int mctrl)
415 struct max3100_port *s = container_of(port,
420 dev_dbg(&s->spi->dev, "%s\n", __func__);
422 rts = (mctrl & TIOCM_RTS) > 0;
424 spin_lock(&s->conf_lock);
430 spin_unlock(&s->conf_lock);
434 max3100_set_termios(struct uart_port *port, struct ktermios *termios,
435 struct ktermios *old)
437 struct max3100_port *s = container_of(port,
442 u32 param_new, param_mask, parity = 0;
444 dev_dbg(&s->spi->dev, "%s\n", __func__);
446 cflag = termios->c_cflag;
449 baud = tty_termios_baud_rate(termios);
450 param_new = s->conf & MAX3100_BAUD;
459 param_new = 14 + s->crystal;
462 param_new = 13 + s->crystal;
465 param_new = 12 + s->crystal;
468 param_new = 11 + s->crystal;
471 param_new = 10 + s->crystal;
474 param_new = 9 + s->crystal;
477 param_new = 8 + s->crystal;
480 param_new = 1 + s->crystal;
483 param_new = 0 + s->crystal;
494 tty_termios_encode_baud_rate(termios, baud, baud);
496 param_mask |= MAX3100_BAUD;
498 if ((cflag & CSIZE) == CS8) {
499 param_new &= ~MAX3100_L;
500 parity &= ~MAX3100_7BIT;
502 param_new |= MAX3100_L;
503 parity |= MAX3100_7BIT;
504 cflag = (cflag & ~CSIZE) | CS7;
506 param_mask |= MAX3100_L;
509 param_new |= MAX3100_ST;
511 param_new &= ~MAX3100_ST;
512 param_mask |= MAX3100_ST;
514 if (cflag & PARENB) {
515 param_new |= MAX3100_PE;
516 parity |= MAX3100_PARITY_ON;
518 param_new &= ~MAX3100_PE;
519 parity &= ~MAX3100_PARITY_ON;
521 param_mask |= MAX3100_PE;
524 parity |= MAX3100_PARITY_ODD;
526 parity &= ~MAX3100_PARITY_ODD;
528 /* mask termios capabilities we don't support */
530 termios->c_cflag = cflag;
532 s->port.ignore_status_mask = 0;
533 if (termios->c_iflag & IGNPAR)
534 s->port.ignore_status_mask |=
535 MAX3100_STATUS_PE | MAX3100_STATUS_FE |
538 /* we are sending char from a workqueue so enable */
539 s->port.state->port.low_latency = 1;
541 if (s->poll_time > 0)
542 del_timer_sync(&s->timer);
544 uart_update_timeout(port, termios->c_cflag, baud);
546 spin_lock(&s->conf_lock);
547 s->conf = (s->conf & ~param_mask) | (param_new & param_mask);
550 spin_unlock(&s->conf_lock);
553 if (UART_ENABLE_MS(&s->port, termios->c_cflag))
554 max3100_enable_ms(&s->port);
557 static void max3100_shutdown(struct uart_port *port)
559 struct max3100_port *s = container_of(port,
563 dev_dbg(&s->spi->dev, "%s\n", __func__);
568 s->force_end_work = 1;
570 if (s->poll_time > 0)
571 del_timer_sync(&s->timer);
574 flush_workqueue(s->workqueue);
575 destroy_workqueue(s->workqueue);
581 /* set shutdown mode to save power */
582 if (s->max3100_hw_suspend)
583 s->max3100_hw_suspend(1);
587 tx = MAX3100_WC | MAX3100_SHDN;
588 max3100_sr(s, tx, &rx);
592 static int max3100_startup(struct uart_port *port)
594 struct max3100_port *s = container_of(port,
599 dev_dbg(&s->spi->dev, "%s\n", __func__);
601 s->conf = MAX3100_RM;
602 s->baud = s->crystal ? 230400 : 115200;
608 s->force_end_work = 0;
612 sprintf(b, "max3100-%d", s->minor);
613 s->workqueue = create_freezable_workqueue(b);
615 dev_warn(&s->spi->dev, "cannot create workqueue\n");
618 INIT_WORK(&s->work, max3100_work);
620 if (request_irq(s->irq, max3100_irq,
621 IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
622 dev_warn(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
624 destroy_workqueue(s->workqueue);
632 max3100_sr(s, tx, &rx);
635 if (s->max3100_hw_suspend)
636 s->max3100_hw_suspend(0);
639 /* wait for clock to settle */
642 max3100_enable_ms(&s->port);
647 static const char *max3100_type(struct uart_port *port)
649 struct max3100_port *s = container_of(port,
653 dev_dbg(&s->spi->dev, "%s\n", __func__);
655 return s->port.type == PORT_MAX3100 ? "MAX3100" : NULL;
658 static void max3100_release_port(struct uart_port *port)
660 struct max3100_port *s = container_of(port,
664 dev_dbg(&s->spi->dev, "%s\n", __func__);
667 static void max3100_config_port(struct uart_port *port, int flags)
669 struct max3100_port *s = container_of(port,
673 dev_dbg(&s->spi->dev, "%s\n", __func__);
675 if (flags & UART_CONFIG_TYPE)
676 s->port.type = PORT_MAX3100;
679 static int max3100_verify_port(struct uart_port *port,
680 struct serial_struct *ser)
682 struct max3100_port *s = container_of(port,
687 dev_dbg(&s->spi->dev, "%s\n", __func__);
689 if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3100)
694 static void max3100_stop_tx(struct uart_port *port)
696 struct max3100_port *s = container_of(port,
700 dev_dbg(&s->spi->dev, "%s\n", __func__);
703 static int max3100_request_port(struct uart_port *port)
705 struct max3100_port *s = container_of(port,
709 dev_dbg(&s->spi->dev, "%s\n", __func__);
713 static void max3100_break_ctl(struct uart_port *port, int break_state)
715 struct max3100_port *s = container_of(port,
719 dev_dbg(&s->spi->dev, "%s\n", __func__);
722 static const struct uart_ops max3100_ops = {
723 .tx_empty = max3100_tx_empty,
724 .set_mctrl = max3100_set_mctrl,
725 .get_mctrl = max3100_get_mctrl,
726 .stop_tx = max3100_stop_tx,
727 .start_tx = max3100_start_tx,
728 .stop_rx = max3100_stop_rx,
729 .enable_ms = max3100_enable_ms,
730 .break_ctl = max3100_break_ctl,
731 .startup = max3100_startup,
732 .shutdown = max3100_shutdown,
733 .set_termios = max3100_set_termios,
734 .type = max3100_type,
735 .release_port = max3100_release_port,
736 .request_port = max3100_request_port,
737 .config_port = max3100_config_port,
738 .verify_port = max3100_verify_port,
741 static struct uart_driver max3100_uart_driver = {
742 .owner = THIS_MODULE,
743 .driver_name = "ttyMAX",
744 .dev_name = "ttyMAX",
745 .major = MAX3100_MAJOR,
746 .minor = MAX3100_MINOR,
749 static int uart_driver_registered;
751 static int max3100_probe(struct spi_device *spi)
754 struct plat_max3100 *pdata;
757 mutex_lock(&max3100s_lock);
759 if (!uart_driver_registered) {
760 retval = uart_register_driver(&max3100_uart_driver);
762 printk(KERN_ERR "Couldn't register max3100 uart driver\n");
763 mutex_unlock(&max3100s_lock);
767 uart_driver_registered = 1;
770 for (i = 0; i < MAX_MAX3100; i++)
773 if (i == MAX_MAX3100) {
774 dev_warn(&spi->dev, "too many MAX3100 chips\n");
775 mutex_unlock(&max3100s_lock);
779 max3100s[i] = kzalloc(sizeof(struct max3100_port), GFP_KERNEL);
782 "kmalloc for max3100 structure %d failed!\n", i);
783 mutex_unlock(&max3100s_lock);
786 max3100s[i]->spi = spi;
787 max3100s[i]->irq = spi->irq;
788 spin_lock_init(&max3100s[i]->conf_lock);
789 spi_set_drvdata(spi, max3100s[i]);
790 pdata = dev_get_platdata(&spi->dev);
791 max3100s[i]->crystal = pdata->crystal;
792 max3100s[i]->loopback = pdata->loopback;
793 max3100s[i]->poll_time = msecs_to_jiffies(pdata->poll_time);
794 if (pdata->poll_time > 0 && max3100s[i]->poll_time == 0)
795 max3100s[i]->poll_time = 1;
796 max3100s[i]->max3100_hw_suspend = pdata->max3100_hw_suspend;
797 max3100s[i]->minor = i;
798 timer_setup(&max3100s[i]->timer, max3100_timeout, 0);
800 dev_dbg(&spi->dev, "%s: adding port %d\n", __func__, i);
801 max3100s[i]->port.irq = max3100s[i]->irq;
802 max3100s[i]->port.uartclk = max3100s[i]->crystal ? 3686400 : 1843200;
803 max3100s[i]->port.fifosize = 16;
804 max3100s[i]->port.ops = &max3100_ops;
805 max3100s[i]->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
806 max3100s[i]->port.line = i;
807 max3100s[i]->port.type = PORT_MAX3100;
808 max3100s[i]->port.dev = &spi->dev;
809 retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port);
812 "uart_add_one_port failed for line %d with error %d\n",
815 /* set shutdown mode to save power. Will be woken-up on open */
816 if (max3100s[i]->max3100_hw_suspend)
817 max3100s[i]->max3100_hw_suspend(1);
819 tx = MAX3100_WC | MAX3100_SHDN;
820 max3100_sr(max3100s[i], tx, &rx);
822 mutex_unlock(&max3100s_lock);
826 static int max3100_remove(struct spi_device *spi)
828 struct max3100_port *s = spi_get_drvdata(spi);
831 mutex_lock(&max3100s_lock);
833 /* find out the index for the chip we are removing */
834 for (i = 0; i < MAX_MAX3100; i++)
835 if (max3100s[i] == s) {
836 dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
837 uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
843 WARN_ON(i == MAX_MAX3100);
845 /* check if this is the last chip we have */
846 for (i = 0; i < MAX_MAX3100; i++)
848 mutex_unlock(&max3100s_lock);
851 pr_debug("removing max3100 driver\n");
852 uart_unregister_driver(&max3100_uart_driver);
853 uart_driver_registered = 0;
855 mutex_unlock(&max3100s_lock);
859 #ifdef CONFIG_PM_SLEEP
861 static int max3100_suspend(struct device *dev)
863 struct max3100_port *s = dev_get_drvdata(dev);
865 dev_dbg(&s->spi->dev, "%s\n", __func__);
870 uart_suspend_port(&max3100_uart_driver, &s->port);
872 if (s->max3100_hw_suspend)
873 s->max3100_hw_suspend(1);
875 /* no HW suspend, so do SW one */
878 tx = MAX3100_WC | MAX3100_SHDN;
879 max3100_sr(s, tx, &rx);
884 static int max3100_resume(struct device *dev)
886 struct max3100_port *s = dev_get_drvdata(dev);
888 dev_dbg(&s->spi->dev, "%s\n", __func__);
890 if (s->max3100_hw_suspend)
891 s->max3100_hw_suspend(0);
892 uart_resume_port(&max3100_uart_driver, &s->port);
904 static SIMPLE_DEV_PM_OPS(max3100_pm_ops, max3100_suspend, max3100_resume);
905 #define MAX3100_PM_OPS (&max3100_pm_ops)
908 #define MAX3100_PM_OPS NULL
911 static struct spi_driver max3100_driver = {
914 .pm = MAX3100_PM_OPS,
916 .probe = max3100_probe,
917 .remove = max3100_remove,
920 module_spi_driver(max3100_driver);
922 MODULE_DESCRIPTION("MAX3100 driver");
923 MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
924 MODULE_LICENSE("GPL");
925 MODULE_ALIAS("spi:max3100");