1 files changed, 243 insertions, 85 deletions

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 468354ef7baa..9e6576004a42 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -25,6 +25,7 @@
 #include <linux/serial.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
+#include <linux/spi/spi.h>
 #include <linux/uaccess.h>
 
 #define SC16IS7XX_NAME			"sc16is7xx"
@@ -300,25 +301,38 @@ struct sc16is7xx_devtype {
 	int	nr_uart;
 };
 
+#define SC16IS7XX_RECONF_MD		(1 << 0)
+#define SC16IS7XX_RECONF_IER		(1 << 1)
+#define SC16IS7XX_RECONF_RS485		(1 << 2)
+
+struct sc16is7xx_one_config {
+	unsigned int			flags;
+	u8				ier_clear;
+};
+
 struct sc16is7xx_one {
 	struct uart_port		port;
-	struct work_struct		tx_work;
-	struct work_struct		md_work;
+	struct kthread_work		tx_work;
+	struct kthread_work		reg_work;
+	struct sc16is7xx_one_config	config;
 };
 
 struct sc16is7xx_port {
 	struct uart_driver		uart;
 	struct sc16is7xx_devtype	*devtype;
 	struct regmap			*regmap;
-	struct mutex			mutex;
 	struct clk			*clk;
 #ifdef CONFIG_GPIOLIB
 	struct gpio_chip		gpio;
 #endif
 	unsigned char			buf[SC16IS7XX_FIFO_SIZE];
+	struct kthread_worker		kworker;
+	struct task_struct		*kworker_task;
+	struct kthread_work		irq_work;
 	struct sc16is7xx_one		p[0];
 };
 
+#define to_sc16is7xx_port(p,e)	((container_of((p), struct sc16is7xx_port, e)))
 #define to_sc16is7xx_one(p,e)	((container_of((p), struct sc16is7xx_one, e)))
 
 static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
@@ -615,9 +629,7 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 					       !!(msr & SC16IS7XX_MSR_CTS_BIT));
 			break;
 		case SC16IS7XX_IIR_THRI_SRC:
-			mutex_lock(&s->mutex);
 			sc16is7xx_handle_tx(port);
-			mutex_unlock(&s->mutex);
 			break;
 		default:
 			dev_err_ratelimited(port->dev,
@@ -628,81 +640,115 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 	} while (1);
 }
 
-static irqreturn_t sc16is7xx_ist(int irq, void *dev_id)
+static void sc16is7xx_ist(struct kthread_work *ws)
 {
-	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
+	struct sc16is7xx_port *s = to_sc16is7xx_port(ws, irq_work);
 	int i;
 
 	for (i = 0; i < s->uart.nr; ++i)
 		sc16is7xx_port_irq(s, i);
+}
+
+static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
+{
+	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
+
+	queue_kthread_work(&s->kworker, &s->irq_work);
 
 	return IRQ_HANDLED;
 }
 
-static void sc16is7xx_wq_proc(struct work_struct *ws)
+static void sc16is7xx_tx_proc(struct kthread_work *ws)
 {
-	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, tx_work);
-	struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
+	struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
+
+	if ((port->rs485.flags & SER_RS485_ENABLED) &&
+	    (port->rs485.delay_rts_before_send > 0))
+		msleep(port->rs485.delay_rts_before_send);
 
-	mutex_lock(&s->mutex);
-	sc16is7xx_handle_tx(&one->port);
-	mutex_unlock(&s->mutex);
+	sc16is7xx_handle_tx(port);
 }
 
-static void sc16is7xx_stop_tx(struct uart_port* port)
+static void sc16is7xx_reconf_rs485(struct uart_port *port)
 {
-	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
-	struct circ_buf *xmit = &one->port.state->xmit;
-
-	/* handle rs485 */
-	if (port->rs485.flags & SER_RS485_ENABLED) {
-		/* do nothing if current tx not yet completed */
-		int lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
-		if (!(lsr & SC16IS7XX_LSR_TEMT_BIT))
-			return;
-
-		if (uart_circ_empty(xmit) &&
-		    (port->rs485.delay_rts_after_send > 0))
-			mdelay(port->rs485.delay_rts_after_send);
+	const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
+			 SC16IS7XX_EFCR_RTS_INVERT_BIT;
+	u32 efcr = 0;
+	struct serial_rs485 *rs485 = &port->rs485;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&port->lock, irqflags);
+	if (rs485->flags & SER_RS485_ENABLED) {
+		efcr |=	SC16IS7XX_EFCR_AUTO_RS485_BIT;
+
+		if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
+			efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
 	}
+	spin_unlock_irqrestore(&port->lock, irqflags);
 
-	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
-			      SC16IS7XX_IER_THRI_BIT,
-			      0);
+	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
 }
 
-static void sc16is7xx_stop_rx(struct uart_port* port)
+static void sc16is7xx_reg_proc(struct kthread_work *ws)
 {
+	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, reg_work);
+	struct sc16is7xx_one_config config;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&one->port.lock, irqflags);
+	config = one->config;
+	memset(&one->config, 0, sizeof(one->config));
+	spin_unlock_irqrestore(&one->port.lock, irqflags);
+
+	if (config.flags & SC16IS7XX_RECONF_MD)
+		sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
+				      SC16IS7XX_MCR_LOOP_BIT,
+				      (one->port.mctrl & TIOCM_LOOP) ?
+				      SC16IS7XX_MCR_LOOP_BIT : 0);
+
+	if (config.flags & SC16IS7XX_RECONF_IER)
+		sc16is7xx_port_update(&one->port, SC16IS7XX_IER_REG,
+				      config.ier_clear, 0);
+
+	if (config.flags & SC16IS7XX_RECONF_RS485)
+		sc16is7xx_reconf_rs485(&one->port);
+}
+
+static void sc16is7xx_ier_clear(struct uart_port *port, u8 bit)
+{
+	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
-	one->port.read_status_mask &= ~SC16IS7XX_LSR_DR_BIT;
-	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
-			      SC16IS7XX_LSR_DR_BIT,
-			      0);
+	one->config.flags |= SC16IS7XX_RECONF_IER;
+	one->config.ier_clear |= bit;
+	queue_kthread_work(&s->kworker, &one->reg_work);
+}
+
+static void sc16is7xx_stop_tx(struct uart_port *port)
+{
+	sc16is7xx_ier_clear(port, SC16IS7XX_IER_THRI_BIT);
+}
+
+static void sc16is7xx_stop_rx(struct uart_port *port)
+{
+	sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
 }
 
 static void sc16is7xx_start_tx(struct uart_port *port)
 {
+	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
-	/* handle rs485 */
-	if ((port->rs485.flags & SER_RS485_ENABLED) &&
-	    (port->rs485.delay_rts_before_send > 0)) {
-		mdelay(port->rs485.delay_rts_before_send);
-	}
-
-	if (!work_pending(&one->tx_work))
-		schedule_work(&one->tx_work);
+	queue_kthread_work(&s->kworker, &one->tx_work);
 }
 
 static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
 {
-	unsigned int lvl, lsr;
+	unsigned int lsr;
 
-	lvl = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
 	lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
 
-	return ((lsr & SC16IS7XX_LSR_THRE_BIT) && !lvl) ? TIOCSER_TEMT : 0;
+	return (lsr & SC16IS7XX_LSR_TEMT_BIT) ? TIOCSER_TEMT : 0;
 }
 
 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
@@ -713,21 +759,13 @@ static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
 	return TIOCM_DSR | TIOCM_CAR;
 }
 
-static void sc16is7xx_md_proc(struct work_struct *ws)
-{
-	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, md_work);
-
-	sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
-			      SC16IS7XX_MCR_LOOP_BIT,
-			      (one->port.mctrl & TIOCM_LOOP) ?
-				      SC16IS7XX_MCR_LOOP_BIT : 0);
-}
-
 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
+	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
-	schedule_work(&one->md_work);
+	one->config.flags |= SC16IS7XX_RECONF_MD;
+	queue_kthread_work(&s->kworker, &one->reg_work);
 }
 
 static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
@@ -831,9 +869,8 @@ static void sc16is7xx_set_termios(struct uart_port *port,
 static int sc16is7xx_config_rs485(struct uart_port *port,
 				  struct serial_rs485 *rs485)
 {
-	const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
-			 SC16IS7XX_EFCR_RTS_INVERT_BIT;
-	u32 efcr = 0;
+	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
+	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
 	if (rs485->flags & SER_RS485_ENABLED) {
 		bool rts_during_rx, rts_during_tx;
@@ -841,21 +878,23 @@ static int sc16is7xx_config_rs485(struct uart_port *port,
 		rts_during_rx = rs485->flags & SER_RS485_RTS_AFTER_SEND;
 		rts_during_tx = rs485->flags & SER_RS485_RTS_ON_SEND;
 
-		efcr |= SC16IS7XX_EFCR_AUTO_RS485_BIT;
-
-		if (!rts_during_rx && rts_during_tx)
-			/* default */;
-		else if (rts_during_rx && !rts_during_tx)
-			efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
-		else
+		if (rts_during_rx == rts_during_tx)
 			dev_err(port->dev,
 				"unsupported RTS signalling on_send:%d after_send:%d - exactly one of RS485 RTS flags should be set\n",
 				rts_during_tx, rts_during_rx);
-	}
 
-	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
+		/*
+		 * RTS signal is handled by HW, it's timing can't be influenced.
+		 * However, it's sometimes useful to delay TX even without RTS
+		 * control therefore we try to handle .delay_rts_before_send.
+		 */
+		if (rs485->delay_rts_after_send)
+			return -EINVAL;
+	}
 
 	port->rs485 = *rs485;
+	one->config.flags |= SC16IS7XX_RECONF_RS485;
+	queue_kthread_work(&s->kworker, &one->reg_work);
 
 	return 0;
 }
@@ -916,6 +955,8 @@ static int sc16is7xx_startup(struct uart_port *port)
 
 static void sc16is7xx_shutdown(struct uart_port *port)
 {
+	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
+
 	/* Disable all interrupts */
 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
 	/* Disable TX/RX */
@@ -926,6 +967,8 @@ static void sc16is7xx_shutdown(struct uart_port *port)
 			      SC16IS7XX_EFCR_TXDISABLE_BIT);
 
 	sc16is7xx_power(port, 0);
+
+	flush_kthread_worker(&s->kworker);
 }
 
 static const char *sc16is7xx_type(struct uart_port *port)
@@ -1043,6 +1086,7 @@ static int sc16is7xx_probe(struct device *dev,
 			   struct sc16is7xx_devtype *devtype,
 			   struct regmap *regmap, int irq, unsigned long flags)
 {
+	struct sched_param sched_param = { .sched_priority = MAX_RT_PRIO / 2 };
 	unsigned long freq, *pfreq = dev_get_platdata(dev);
 	int i, ret;
 	struct sc16is7xx_port *s;
@@ -1084,6 +1128,16 @@ static int sc16is7xx_probe(struct device *dev,
 		goto out_clk;
 	}
 
+	init_kthread_worker(&s->kworker);
+	init_kthread_work(&s->irq_work, sc16is7xx_ist);
+	s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
+				      "sc16is7xx");
+	if (IS_ERR(s->kworker_task)) {
+		ret = PTR_ERR(s->kworker_task);
+		goto out_uart;
+	}
+	sched_setscheduler(s->kworker_task, SCHED_FIFO, &sched_param);
+
 #ifdef CONFIG_GPIOLIB
 	if (devtype->nr_gpio) {
 		/* Setup GPIO cotroller */
@@ -1099,12 +1153,10 @@ static int sc16is7xx_probe(struct device *dev,
 		s->gpio.can_sleep	 = 1;
 		ret = gpiochip_add(&s->gpio);
 		if (ret)
-			goto out_uart;
+			goto out_thread;
 	}
 #endif
 
-	mutex_init(&s->mutex);
-
 	for (i = 0; i < devtype->nr_uart; ++i) {
 		/* Initialize port data */
 		s->p[i].port.line	= i;
@@ -1123,10 +1175,9 @@ static int sc16is7xx_probe(struct device *dev,
 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
 				     SC16IS7XX_EFCR_RXDISABLE_BIT |
 				     SC16IS7XX_EFCR_TXDISABLE_BIT);
-		/* Initialize queue for start TX */
-		INIT_WORK(&s->p[i].tx_work, sc16is7xx_wq_proc);
-		/* Initialize queue for changing mode */
-		INIT_WORK(&s->p[i].md_work, sc16is7xx_md_proc);
+		/* Initialize kthread work structs */
+		init_kthread_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
+		init_kthread_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
 		/* Register port */
 		uart_add_one_port(&s->uart, &s->p[i].port);
 		/* Go to suspend mode */
@@ -1134,22 +1185,23 @@ static int sc16is7xx_probe(struct device *dev,
 	}
 
 	/* Setup interrupt */
-	ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_ist,
-					IRQF_ONESHOT | flags, dev_name(dev), s);
+	ret = devm_request_irq(dev, irq, sc16is7xx_irq,
+			       IRQF_ONESHOT | flags, dev_name(dev), s);
 	if (!ret)
 		return 0;
 
 	for (i = 0; i < s->uart.nr; i++)
 		uart_remove_one_port(&s->uart, &s->p[i].port);
 
-	mutex_destroy(&s->mutex);
-
 #ifdef CONFIG_GPIOLIB
 	if (devtype->nr_gpio)
 		gpiochip_remove(&s->gpio);
 
-out_uart:
+out_thread:
 #endif
+	kthread_stop(s->kworker_task);
+
+out_uart:
 	uart_unregister_driver(&s->uart);
 
 out_clk:
@@ -1170,13 +1222,13 @@ static int sc16is7xx_remove(struct device *dev)
 #endif
 
 	for (i = 0; i < s->uart.nr; i++) {
-		cancel_work_sync(&s->p[i].tx_work);
-		cancel_work_sync(&s->p[i].md_work);
 		uart_remove_one_port(&s->uart, &s->p[i].port);
 		sc16is7xx_power(&s->p[i].port, 0);
 	}
 
-	mutex_destroy(&s->mutex);
+	flush_kthread_worker(&s->kworker);
+	kthread_stop(s->kworker_task);
+
 	uart_unregister_driver(&s->uart);
 	if (!IS_ERR(s->clk))
 		clk_disable_unprepare(s->clk);
@@ -1204,6 +1256,75 @@ static struct regmap_config regcfg = {
 	.precious_reg = sc16is7xx_regmap_precious,
 };
 
+#ifdef CONFIG_SERIAL_SC16IS7XX_SPI
+static int sc16is7xx_spi_probe(struct spi_device *spi)
+{
+	struct sc16is7xx_devtype *devtype;
+	unsigned long flags = 0;
+	struct regmap *regmap;
+	int ret;
+
+	/* Setup SPI bus */
+	spi->bits_per_word	= 8;
+	/* only supports mode 0 on SC16IS762 */
+	spi->mode		= spi->mode ? : SPI_MODE_0;
+	spi->max_speed_hz	= spi->max_speed_hz ? : 15000000;
+	ret = spi_setup(spi);
+	if (ret)
+		return ret;
+
+	if (spi->dev.of_node) {
+		const struct of_device_id *of_id =
+			of_match_device(sc16is7xx_dt_ids, &spi->dev);
+
+		devtype = (struct sc16is7xx_devtype *)of_id->data;
+	} else {
+		const struct spi_device_id *id_entry = spi_get_device_id(spi);
+
+		devtype = (struct sc16is7xx_devtype *)id_entry->driver_data;
+		flags = IRQF_TRIGGER_FALLING;
+	}
+
+	regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
+			      (devtype->nr_uart - 1);
+	regmap = devm_regmap_init_spi(spi, &regcfg);
+
+	return sc16is7xx_probe(&spi->dev, devtype, regmap, spi->irq, flags);
+}
+
+static int sc16is7xx_spi_remove(struct spi_device *spi)
+{
+	return sc16is7xx_remove(&spi->dev);
+}
+
+static const struct spi_device_id sc16is7xx_spi_id_table[] = {
+	{ "sc16is74x",	(kernel_ulong_t)&sc16is74x_devtype, },
+	{ "sc16is740",	(kernel_ulong_t)&sc16is74x_devtype, },
+	{ "sc16is741",	(kernel_ulong_t)&sc16is74x_devtype, },
+	{ "sc16is750",	(kernel_ulong_t)&sc16is750_devtype, },
+	{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
+	{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
+	{ "sc16is762",	(kernel_ulong_t)&sc16is762_devtype, },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(spi, sc16is7xx_spi_id_table);
+
+static struct spi_driver sc16is7xx_spi_uart_driver = {
+	.driver = {
+		.name		= SC16IS7XX_NAME,
+		.owner		= THIS_MODULE,
+		.of_match_table	= of_match_ptr(sc16is7xx_dt_ids),
+	},
+	.probe		= sc16is7xx_spi_probe,
+	.remove		= sc16is7xx_spi_remove,
+	.id_table	= sc16is7xx_spi_id_table,
+};
+
+MODULE_ALIAS("spi:sc16is7xx");
+#endif
+
+#ifdef CONFIG_SERIAL_SC16IS7XX_I2C
 static int sc16is7xx_i2c_probe(struct i2c_client *i2c,
 			       const struct i2c_device_id *id)
 {
@@ -1235,6 +1356,8 @@ static int sc16is7xx_i2c_remove(struct i2c_client *client)
 
 static const struct i2c_device_id sc16is7xx_i2c_id_table[] = {
 	{ "sc16is74x",	(kernel_ulong_t)&sc16is74x_devtype, },
+	{ "sc16is740",	(kernel_ulong_t)&sc16is74x_devtype, },
+	{ "sc16is741",	(kernel_ulong_t)&sc16is74x_devtype, },
 	{ "sc16is750",	(kernel_ulong_t)&sc16is750_devtype, },
 	{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
 	{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
@@ -1253,8 +1376,43 @@ static struct i2c_driver sc16is7xx_i2c_uart_driver = {
 	.remove		= sc16is7xx_i2c_remove,
 	.id_table	= sc16is7xx_i2c_id_table,
 };
-module_i2c_driver(sc16is7xx_i2c_uart_driver);
+
 MODULE_ALIAS("i2c:sc16is7xx");
+#endif
+
+static int __init sc16is7xx_init(void)
+{
+	int ret = 0;
+#ifdef CONFIG_SERIAL_SC16IS7XX_I2C
+	ret = i2c_add_driver(&sc16is7xx_i2c_uart_driver);
+	if (ret < 0) {
+		pr_err("failed to init sc16is7xx i2c --> %d\n", ret);
+		return ret;
+	}
+#endif
+
+#ifdef CONFIG_SERIAL_SC16IS7XX_SPI
+	ret = spi_register_driver(&sc16is7xx_spi_uart_driver);
+	if (ret < 0) {
+		pr_err("failed to init sc16is7xx spi --> %d\n", ret);
+		return ret;
+	}
+#endif
+	return ret;
+}
+module_init(sc16is7xx_init);
+
+static void __exit sc16is7xx_exit(void)
+{
+#ifdef CONFIG_SERIAL_SC16IS7XX_I2C
+	i2c_del_driver(&sc16is7xx_i2c_uart_driver);
+#endif
+
+#ifdef CONFIG_SERIAL_SC16IS7XX_SPI
+	spi_unregister_driver(&sc16is7xx_spi_uart_driver);
+#endif
+}
+module_exit(sc16is7xx_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");