/* * * Copyright (C) 2008 Christian Pellegrin <chripell@evolware.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * * Notes: the MAX3100 doesn't provide an interrupt on CTS so we have * to use polling for flow control. TX empty IRQ is unusable, since * writing conf clears FIFO buffer and we cannot have this interrupt * always asking us for attention. * * Example platform data: static struct plat_max3100 max3100_plat_data = { .loopback = 0, .crystal = 0, .poll_time = 100, }; static struct spi_board_info spi_board_info[] = { { .modalias = "max3100", .platform_data = &max3100_plat_data, .irq = IRQ_EINT12, .max_speed_hz = 5*1000*1000, .chip_select = 0, }, }; * The initial minor number is 209 in the low-density serial port: * mknod /dev/ttyMAX0 c 204 209 */ #define MAX3100_MAJOR 204 #define MAX3100_MINOR 209 /* 4 MAX3100s should be enough for everyone */ #define MAX_MAX3100 4 #include <linux/delay.h> #include <linux/slab.h> #include <linux/device.h> #include <linux/serial_core.h> #include <linux/serial.h> #include <linux/spi/spi.h> #include <linux/freezer.h> #include <linux/serial_max3100.h> #define MAX3100_C (1<<14) #define MAX3100_D (0<<14) #define MAX3100_W (1<<15) #define MAX3100_RX (0<<15) #define MAX3100_WC (MAX3100_W | MAX3100_C) #define MAX3100_RC (MAX3100_RX | MAX3100_C) #define MAX3100_WD (MAX3100_W | MAX3100_D) #define MAX3100_RD (MAX3100_RX | MAX3100_D) #define MAX3100_CMD (3 << 14) #define MAX3100_T (1<<14) #define MAX3100_R (1<<15) #define MAX3100_FEN (1<<13) #define MAX3100_SHDN (1<<12) #define MAX3100_TM (1<<11) #define MAX3100_RM (1<<10) #define MAX3100_PM (1<<9) #define MAX3100_RAM (1<<8) #define MAX3100_IR (1<<7) #define MAX3100_ST (1<<6) #define MAX3100_PE (1<<5) #define MAX3100_L (1<<4) #define MAX3100_BAUD (0xf) #define MAX3100_TE (1<<10) #define MAX3100_RAFE (1<<10) #define MAX3100_RTS (1<<9) #define MAX3100_CTS (1<<9) #define MAX3100_PT (1<<8) #define MAX3100_DATA (0xff) #define MAX3100_RT (MAX3100_R | MAX3100_T) #define MAX3100_RTC (MAX3100_RT | MAX3100_CTS | MAX3100_RAFE) /* the following simulate a status reg for ignore_status_mask */ #define MAX3100_STATUS_PE 1 #define MAX3100_STATUS_FE 2 #define MAX3100_STATUS_OE 4 struct max3100_port { struct uart_port port; struct spi_device *spi; int cts; /* last CTS received for flow ctrl */ int tx_empty; /* last TX empty bit */ spinlock_t conf_lock; /* shared data */ int conf_commit; /* need to make changes */ int conf; /* configuration for the MAX31000 * (bits 0-7, bits 8-11 are irqs) */ int rts_commit; /* need to change rts */ int rts; /* rts status */ int baud; /* current baud rate */ int parity; /* keeps track if we should send parity */ #define MAX3100_PARITY_ON 1 #define MAX3100_PARITY_ODD 2 #define MAX3100_7BIT 4 int rx_enabled; /* if we should rx chars */ int irq; /* irq assigned to the max3100 */ int minor; /* minor number */ int crystal; /* 1 if 3.6864Mhz crystal 0 for 1.8432 */ int loopback; /* 1 if we are in loopback mode */ /* for handling irqs: need workqueue since we do spi_sync */ struct workqueue_struct *workqueue; struct work_struct work; /* set to 1 to make the workhandler exit as soon as possible */ int force_end_work; /* need to know we are suspending to avoid deadlock on workqueue */ int suspending; /* hook for suspending MAX3100 via dedicated pin */ void (*max3100_hw_suspend) (int suspend); /* poll time (in ms) for ctrl lines */ int poll_time; /* and its timer */ struct timer_list timer; }; static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */ static DEFINE_MUTEX(max3100s_lock); /* race on probe */ static int max3100_do_parity(struct max3100_port *s, u16 c) { int parity; if (s->parity & MAX3100_PARITY_ODD) parity = 1; else parity = 0; if (s->parity & MAX3100_7BIT) c &= 0x7f; else c &= 0xff; parity = parity ^ (hweight8(c) & 1); return parity; } static int max3100_check_parity(struct max3100_port *s, u16 c) { return max3100_do_parity(s, c) == ((c >> 8) & 1); } static void max3100_calc_parity(struct max3100_port *s, u16 *c) { if (s->parity & MAX3100_7BIT) *c &= 0x7f; else *c &= 0xff; if (s->parity & MAX3100_PARITY_ON) *c |= max3100_do_parity(s, *c) << 8; } static void max3100_work(struct work_struct *w); static void max3100_dowork(struct max3100_port *s) { if (!s->force_end_work && !work_pending(&s->work) && !freezing(current) && !s->suspending) queue_work(s->workqueue, &s->work); } static void max3100_timeout(unsigned long data) { struct max3100_port *s = (struct max3100_port *)data; if (s->port.state) { max3100_dowork(s); mod_timer(&s->timer, jiffies + s->poll_time); } } static int max3100_sr(struct max3100_port *s, u16 tx, u16 *rx) { struct spi_message message; u16 etx, erx; int status; struct spi_transfer tran = { .tx_buf = &etx, .rx_buf = &erx, .len = 2, }; etx = cpu_to_be16(tx); spi_message_init(&message); spi_message_add_tail(&tran, &message); status = spi_sync(s->spi, &message); if (status) { dev_warn(&s->spi->dev, "error while calling spi_sync\n"); return -EIO; } *rx = be16_to_cpu(erx); s->tx_empty = (*rx & MAX3100_T) > 0; dev_dbg(&s->spi->dev, "%04x - %04x\n", tx, *rx); return 0; } static int max3100_handlerx(struct max3100_port *s, u16 rx) { unsigned int ch, flg, status = 0; int ret = 0, cts; if (rx & MAX3100_R && s->rx_enabled) { dev_dbg(&s->spi->dev, "%s\n", __func__); ch = rx & (s->parity & MAX3100_7BIT ? 0x7f : 0xff); if (rx & MAX3100_RAFE) { s->port.icount.frame++; flg = TTY_FRAME; status |= MAX3100_STATUS_FE; } else { if (s->parity & MAX3100_PARITY_ON) { if (max3100_check_parity(s, rx)) { s->port.icount.rx++; flg = TTY_NORMAL; } else { s->port.icount.parity++; flg = TTY_PARITY; status |= MAX3100_STATUS_PE; } } else { s->port.icount.rx++; flg = TTY_NORMAL; } } uart_insert_char(&s->port, status, MAX3100_STATUS_OE, ch, flg); ret = 1; } cts = (rx & MAX3100_CTS) > 0; if (s->cts != cts) { s->cts = cts; uart_handle_cts_change(&s->port, cts ? TIOCM_CTS : 0); } return ret; } static void max3100_work(struct work_struct *w) { struct max3100_port *s = container_of(w, struct max3100_port, work); int rxchars; u16 tx, rx; int conf, cconf, rts, crts; struct circ_buf *xmit = &s->port.state->xmit; dev_dbg(&s->spi->dev, "%s\n", __func__); rxchars = 0; do { spin_lock(&s->conf_lock); conf = s->conf; cconf = s->conf_commit; s->conf_commit = 0; rts = s->rts; crts = s->rts_commit; s->rts_commit = 0; spin_unlock(&s->conf_lock); if (cconf) max3100_sr(s, MAX3100_WC | conf, &rx); if (crts) { max3100_sr(s, MAX3100_WD | MAX3100_TE | (s->rts ? MAX3100_RTS : 0), &rx); rxchars += max3100_handlerx(s, rx); } max3100_sr(s, MAX3100_RD, &rx); rxchars += max3100_handlerx(s, rx); if (rx & MAX3100_T) { tx = 0xffff; if (s->port.x_char) { tx = s->port.x_char; s->port.icount.tx++; s->port.x_char = 0; } else if (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) { tx = xmit->buf[xmit->tail]; xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); s->port.icount.tx++; } if (tx != 0xffff) { max3100_calc_parity(s, &tx); tx |= MAX3100_WD | (s->rts ? MAX3100_RTS : 0); max3100_sr(s, tx, &rx); rxchars += max3100_handlerx(s, rx); } } if (rxchars > 16 && s->port.state->port.tty != NULL) { tty_flip_buffer_push(s->port.state->port.tty); rxchars = 0; } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&s->port); } while (!s->force_end_work && !freezing(current) && ((rx & MAX3100_R) || (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)))); if (rxchars > 0 && s->port.state->port.tty != NULL) tty_flip_buffer_push(s->port.state->port.tty); } static irqreturn_t max3100_irq(int irqno, void *dev_id) { struct max3100_port *s = dev_id; dev_dbg(&s->spi->dev, "%s\n", __func__); max3100_dowork(s); return IRQ_HANDLED; } static void max3100_enable_ms(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); if (s->poll_time > 0) mod_timer(&s->timer, jiffies); dev_dbg(&s->spi->dev, "%s\n", __func__); } static void max3100_start_tx(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); max3100_dowork(s); } static void max3100_stop_rx(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); s->rx_enabled = 0; spin_lock(&s->conf_lock); s->conf &= ~MAX3100_RM; s->conf_commit = 1; spin_unlock(&s->conf_lock); max3100_dowork(s); } static unsigned int max3100_tx_empty(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); /* may not be truly up-to-date */ max3100_dowork(s); return s->tx_empty; } static unsigned int max3100_get_mctrl(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); /* may not be truly up-to-date */ max3100_dowork(s); /* always assert DCD and DSR since these lines are not wired */ return (s->cts ? TIOCM_CTS : 0) | TIOCM_DSR | TIOCM_CAR; } static void max3100_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct max3100_port *s = container_of(port, struct max3100_port, port); int rts; dev_dbg(&s->spi->dev, "%s\n", __func__); rts = (mctrl & TIOCM_RTS) > 0; spin_lock(&s->conf_lock); if (s->rts != rts) { s->rts = rts; s->rts_commit = 1; max3100_dowork(s); } spin_unlock(&s->conf_lock); } static void max3100_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { struct max3100_port *s = container_of(port, struct max3100_port, port); int baud = 0; unsigned cflag; u32 param_new, param_mask, parity = 0; struct tty_struct *tty = s->port.state->port.tty; dev_dbg(&s->spi->dev, "%s\n", __func__); if (!tty) return; cflag = termios->c_cflag; param_new = 0; param_mask = 0; baud = tty_get_baud_rate(tty); param_new = s->conf & MAX3100_BAUD; switch (baud) { case 300: if (s->crystal) baud = s->baud; else param_new = 15; break; case 600: param_new = 14 + s->crystal; break; case 1200: param_new = 13 + s->crystal; break; case 2400: param_new = 12 + s->crystal; break; case 4800: param_new = 11 + s->crystal; break; case 9600: param_new = 10 + s->crystal; break; case 19200: param_new = 9 + s->crystal; break; case 38400: param_new = 8 + s->crystal; break; case 57600: param_new = 1 + s->crystal; break; case 115200: param_new = 0 + s->crystal; break; case 230400: if (s->crystal) param_new = 0; else baud = s->baud; break; default: baud = s->baud; } tty_encode_baud_rate(tty, baud, baud); s->baud = baud; param_mask |= MAX3100_BAUD; if ((cflag & CSIZE) == CS8) { param_new &= ~MAX3100_L; parity &= ~MAX3100_7BIT; } else { param_new |= MAX3100_L; parity |= MAX3100_7BIT; cflag = (cflag & ~CSIZE) | CS7; } param_mask |= MAX3100_L; if (cflag & CSTOPB) param_new |= MAX3100_ST; else param_new &= ~MAX3100_ST; param_mask |= MAX3100_ST; if (cflag & PARENB) { param_new |= MAX3100_PE; parity |= MAX3100_PARITY_ON; } else { param_new &= ~MAX3100_PE; parity &= ~MAX3100_PARITY_ON; } param_mask |= MAX3100_PE; if (cflag & PARODD) parity |= MAX3100_PARITY_ODD; else parity &= ~MAX3100_PARITY_ODD; /* mask termios capabilities we don't support */ cflag &= ~CMSPAR; termios->c_cflag = cflag; s->port.ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) s->port.ignore_status_mask |= MAX3100_STATUS_PE | MAX3100_STATUS_FE | MAX3100_STATUS_OE; /* we are sending char from a workqueue so enable */ s->port.state->port.tty->low_latency = 1; if (s->poll_time > 0) del_timer_sync(&s->timer); uart_update_timeout(port, termios->c_cflag, baud); spin_lock(&s->conf_lock); s->conf = (s->conf & ~param_mask) | (param_new & param_mask); s->conf_commit = 1; s->parity = parity; spin_unlock(&s->conf_lock); max3100_dowork(s); if (UART_ENABLE_MS(&s->port, termios->c_cflag)) max3100_enable_ms(&s->port); } static void max3100_shutdown(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); if (s->suspending) return; s->force_end_work = 1; if (s->poll_time > 0) del_timer_sync(&s->timer); if (s->workqueue) { flush_workqueue(s->workqueue); destroy_workqueue(s->workqueue); s->workqueue = NULL; } if (s->irq) free_irq(s->irq, s); /* set shutdown mode to save power */ if (s->max3100_hw_suspend) s->max3100_hw_suspend(1); else { u16 tx, rx; tx = MAX3100_WC | MAX3100_SHDN; max3100_sr(s, tx, &rx); } } static int max3100_startup(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); char b[12]; dev_dbg(&s->spi->dev, "%s\n", __func__); s->conf = MAX3100_RM; s->baud = s->crystal ? 230400 : 115200; s->rx_enabled = 1; if (s->suspending) return 0; s->force_end_work = 0; s->parity = 0; s->rts = 0; sprintf(b, "max3100-%d", s->minor); s->workqueue = create_freezeable_workqueue(b); if (!s->workqueue) { dev_warn(&s->spi->dev, "cannot create workqueue\n"); return -EBUSY; } INIT_WORK(&s->work, max3100_work); if (request_irq(s->irq, max3100_irq, IRQF_TRIGGER_FALLING, "max3100", s) < 0) { dev_warn(&s->spi->dev, "cannot allocate irq %d\n", s->irq); s->irq = 0; destroy_workqueue(s->workqueue); s->workqueue = NULL; return -EBUSY; } if (s->loopback) { u16 tx, rx; tx = 0x4001; max3100_sr(s, tx, &rx); } if (s->max3100_hw_suspend) s->max3100_hw_suspend(0); s->conf_commit = 1; max3100_dowork(s); /* wait for clock to settle */ msleep(50); max3100_enable_ms(&s->port); return 0; } static const char *max3100_type(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); return s->port.type == PORT_MAX3100 ? "MAX3100" : NULL; } static void max3100_release_port(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); } static void max3100_config_port(struct uart_port *port, int flags) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); if (flags & UART_CONFIG_TYPE) s->port.type = PORT_MAX3100; } static int max3100_verify_port(struct uart_port *port, struct serial_struct *ser) { struct max3100_port *s = container_of(port, struct max3100_port, port); int ret = -EINVAL; dev_dbg(&s->spi->dev, "%s\n", __func__); if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3100) ret = 0; return ret; } static void max3100_stop_tx(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); } static int max3100_request_port(struct uart_port *port) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); return 0; } static void max3100_break_ctl(struct uart_port *port, int break_state) { struct max3100_port *s = container_of(port, struct max3100_port, port); dev_dbg(&s->spi->dev, "%s\n", __func__); } static struct uart_ops max3100_ops = { .tx_empty = max3100_tx_empty, .set_mctrl = max3100_set_mctrl, .get_mctrl = max3100_get_mctrl, .stop_tx = max3100_stop_tx, .start_tx = max3100_start_tx, .stop_rx = max3100_stop_rx, .enable_ms = max3100_enable_ms, .break_ctl = max3100_break_ctl, .startup = max3100_startup, .shutdown = max3100_shutdown, .set_termios = max3100_set_termios, .type = max3100_type, .release_port = max3100_release_port, .request_port = max3100_request_port, .config_port = max3100_config_port, .verify_port = max3100_verify_port, }; static struct uart_driver max3100_uart_driver = { .owner = THIS_MODULE, .driver_name = "ttyMAX", .dev_name = "ttyMAX", .major = MAX3100_MAJOR, .minor = MAX3100_MINOR, .nr = MAX_MAX3100, }; static int uart_driver_registered; static int __devinit max3100_probe(struct spi_device *spi) { int i, retval; struct plat_max3100 *pdata; u16 tx, rx; mutex_lock(&max3100s_lock); if (!uart_driver_registered) { uart_driver_registered = 1; retval = uart_register_driver(&max3100_uart_driver); if (retval) { printk(KERN_ERR "Couldn't register max3100 uart driver\n"); mutex_unlock(&max3100s_lock); return retval; } } for (i = 0; i < MAX_MAX3100; i++) if (!max3100s[i]) break; if (i == MAX_MAX3100) { dev_warn(&spi->dev, "too many MAX3100 chips\n"); mutex_unlock(&max3100s_lock); return -ENOMEM; } max3100s[i] = kzalloc(sizeof(struct max3100_port), GFP_KERNEL); if (!max3100s[i]) { dev_warn(&spi->dev, "kmalloc for max3100 structure %d failed!\n", i); mutex_unlock(&max3100s_lock); return -ENOMEM; } max3100s[i]->spi = spi; max3100s[i]->irq = spi->irq; spin_lock_init(&max3100s[i]->conf_lock); dev_set_drvdata(&spi->dev, max3100s[i]); pdata = spi->dev.platform_data; max3100s[i]->crystal = pdata->crystal; max3100s[i]->loopback = pdata->loopback; max3100s[i]->poll_time = pdata->poll_time * HZ / 1000; if (pdata->poll_time > 0 && max3100s[i]->poll_time == 0) max3100s[i]->poll_time = 1; max3100s[i]->max3100_hw_suspend = pdata->max3100_hw_suspend; max3100s[i]->minor = i; init_timer(&max3100s[i]->timer); max3100s[i]->timer.function = max3100_timeout; max3100s[i]->timer.data = (unsigned long) max3100s[i]; dev_dbg(&spi->dev, "%s: adding port %d\n", __func__, i); max3100s[i]->port.irq = max3100s[i]->irq; max3100s[i]->port.uartclk = max3100s[i]->crystal ? 3686400 : 1843200; max3100s[i]->port.fifosize = 16; max3100s[i]->port.ops = &max3100_ops; max3100s[i]->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF; max3100s[i]->port.line = i; max3100s[i]->port.type = PORT_MAX3100; max3100s[i]->port.dev = &spi->dev; retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port); if (retval < 0) dev_warn(&spi->dev, "uart_add_one_port failed for line %d with error %d\n", i, retval); /* set shutdown mode to save power. Will be woken-up on open */ if (max3100s[i]->max3100_hw_suspend) max3100s[i]->max3100_hw_suspend(1); else { tx = MAX3100_WC | MAX3100_SHDN; max3100_sr(max3100s[i], tx, &rx); } mutex_unlock(&max3100s_lock); return 0; } static int __devexit max3100_remove(struct spi_device *spi) { struct max3100_port *s = dev_get_drvdata(&spi->dev); int i; mutex_lock(&max3100s_lock); /* find out the index for the chip we are removing */ for (i = 0; i < MAX_MAX3100; i++) if (max3100s[i] == s) break; dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i); uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port); kfree(max3100s[i]); max3100s[i] = NULL; /* check if this is the last chip we have */ for (i = 0; i < MAX_MAX3100; i++) if (max3100s[i]) { mutex_unlock(&max3100s_lock); return 0; } pr_debug("removing max3100 driver\n"); uart_unregister_driver(&max3100_uart_driver); mutex_unlock(&max3100s_lock); return 0; } #ifdef CONFIG_PM static int max3100_suspend(struct spi_device *spi, pm_message_t state) { struct max3100_port *s = dev_get_drvdata(&spi->dev); dev_dbg(&s->spi->dev, "%s\n", __func__); disable_irq(s->irq); s->suspending = 1; uart_suspend_port(&max3100_uart_driver, &s->port); if (s->max3100_hw_suspend) s->max3100_hw_suspend(1); else { /* no HW suspend, so do SW one */ u16 tx, rx; tx = MAX3100_WC | MAX3100_SHDN; max3100_sr(s, tx, &rx); } return 0; } static int max3100_resume(struct spi_device *spi) { struct max3100_port *s = dev_get_drvdata(&spi->dev); dev_dbg(&s->spi->dev, "%s\n", __func__); if (s->max3100_hw_suspend) s->max3100_hw_suspend(0); uart_resume_port(&max3100_uart_driver, &s->port); s->suspending = 0; enable_irq(s->irq); s->conf_commit = 1; if (s->workqueue) max3100_dowork(s); return 0; } #else #define max3100_suspend NULL #define max3100_resume NULL #endif static struct spi_driver max3100_driver = { .driver = { .name = "max3100", .bus = &spi_bus_type, .owner = THIS_MODULE, }, .probe = max3100_probe, .remove = __devexit_p(max3100_remove), .suspend = max3100_suspend, .resume = max3100_resume, }; static int __init max3100_init(void) { return spi_register_driver(&max3100_driver); } module_init(max3100_init); static void __exit max3100_exit(void) { spi_unregister_driver(&max3100_driver); } module_exit(max3100_exit); MODULE_DESCRIPTION("MAX3100 driver"); MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:max3100");