sc16is7xx: support multiple devices

We currently register the uart driver during device probe
which makes it hard to support more than one chip.
Move the driver registration to module init/exit time and
preallocate space for up to 8 lines (4-8 chips).

Reported-by: Michael Allwright <michael.allwright@upb.de>
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index b968cc5..15610cb 100644 (file)
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -11,6 +11,8 @@
  *
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
@@ -29,6 +31,7 @@
 #include <linux/uaccess.h>
 
 #define SC16IS7XX_NAME                 "sc16is7xx"
+#define SC16IS7XX_MAX_DEVS             8
 
 /* SC16IS7XX register definitions */
 #define SC16IS7XX_RHR_REG              (0x00) /* RX FIFO */
@@ -319,7 +322,6 @@ struct sc16is7xx_one {
 };
 
 struct sc16is7xx_port {
-       struct uart_driver              uart;
        struct sc16is7xx_devtype        *devtype;
        struct regmap                   *regmap;
        struct clk                      *clk;
@@ -333,6 +335,14 @@ struct sc16is7xx_port {
        struct sc16is7xx_one            p[0];
 };
 
+static unsigned long sc16is7xx_lines;
+
+static struct uart_driver sc16is7xx_uart = {
+       .owner          = THIS_MODULE,
+       .dev_name       = "ttySC",
+       .nr             = SC16IS7XX_MAX_DEVS,
+};
+
 #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)))
 
@@ -394,6 +404,18 @@ static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
                           mask, val);
 }
 
+static int sc16is7xx_alloc_line(void)
+{
+       int i;
+
+       BUILD_BUG_ON(SC16IS7XX_MAX_DEVS > BITS_PER_LONG);
+
+       for (i = 0; i < SC16IS7XX_MAX_DEVS; i++)
+               if (!test_and_set_bit(i, &sc16is7xx_lines))
+                       break;
+
+       return i;
+}
 
 static void sc16is7xx_power(struct uart_port *port, int on)
 {
@@ -671,7 +693,7 @@ static void sc16is7xx_ist(struct kthread_work *ws)
        struct sc16is7xx_port *s = to_sc16is7xx_port(ws, irq_work);
        int i;
 
-       for (i = 0; i < s->uart.nr; ++i)
+       for (i = 0; i < s->devtype->nr_uart; ++i)
                sc16is7xx_port_irq(s, i);
 }
 
@@ -1144,23 +1166,13 @@ static int sc16is7xx_probe(struct device *dev,
        s->devtype = devtype;
        dev_set_drvdata(dev, s);
 
-       /* Register UART driver */
-       s->uart.owner           = THIS_MODULE;
-       s->uart.dev_name        = "ttySC";
-       s->uart.nr              = devtype->nr_uart;
-       ret = uart_register_driver(&s->uart);
-       if (ret) {
-               dev_err(dev, "Registering UART driver failed\n");
-               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;
+               goto out_clk;
        }
        sched_setscheduler(s->kworker_task, SCHED_FIFO, &sched_param);
 
@@ -1186,7 +1198,6 @@ static int sc16is7xx_probe(struct device *dev,
        for (i = 0; i < devtype->nr_uart; ++i) {
                s->p[i].line            = i;
                /* Initialize port data */
-               s->p[i].port.line       = i;
                s->p[i].port.dev        = dev;
                s->p[i].port.irq        = irq;
                s->p[i].port.type       = PORT_SC16IS7XX;
@@ -1196,6 +1207,12 @@ static int sc16is7xx_probe(struct device *dev,
                s->p[i].port.uartclk    = freq;
                s->p[i].port.rs485_config = sc16is7xx_config_rs485;
                s->p[i].port.ops        = &sc16is7xx_ops;
+               s->p[i].port.line       = sc16is7xx_alloc_line();
+               if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
+                       ret = -ENOMEM;
+                       goto out_ports;
+               }
+
                /* Disable all interrupts */
                sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
                /* Disable TX/RX */
@@ -1206,7 +1223,7 @@ static int sc16is7xx_probe(struct device *dev,
                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);
+               uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
                /* Go to suspend mode */
                sc16is7xx_power(&s->p[i].port, 0);
        }
@@ -1217,8 +1234,11 @@ static int sc16is7xx_probe(struct device *dev,
        if (!ret)
                return 0;
 
-       for (i = 0; i < s->uart.nr; i++)
-               uart_remove_one_port(&s->uart, &s->p[i].port);
+out_ports:
+       for (i--; i >= 0; i--) {
+               uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
+               clear_bit(s->p[i].port.line, &sc16is7xx_lines);
+       }
 
 #ifdef CONFIG_GPIOLIB
        if (devtype->nr_gpio)
@@ -1228,9 +1248,6 @@ out_thread:
 #endif
        kthread_stop(s->kworker_task);
 
-out_uart:
-       uart_unregister_driver(&s->uart);
-
 out_clk:
        if (!IS_ERR(s->clk))
                clk_disable_unprepare(s->clk);
@@ -1248,15 +1265,15 @@ static int sc16is7xx_remove(struct device *dev)
                gpiochip_remove(&s->gpio);
 #endif
 
-       for (i = 0; i < s->uart.nr; i++) {
-               uart_remove_one_port(&s->uart, &s->p[i].port);
+       for (i = 0; i < s->devtype->nr_uart; i++) {
+               uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
+               clear_bit(s->p[i].port.line, &sc16is7xx_lines);
                sc16is7xx_power(&s->p[i].port, 0);
        }
 
        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);
 
@@ -1408,7 +1425,14 @@ MODULE_ALIAS("i2c:sc16is7xx");
 
 static int __init sc16is7xx_init(void)
 {
-       int ret = 0;
+       int ret;
+
+       ret = uart_register_driver(&sc16is7xx_uart);
+       if (ret) {
+               pr_err("Registering UART driver failed\n");
+               return ret;
+       }
+
 #ifdef CONFIG_SERIAL_SC16IS7XX_I2C
        ret = i2c_add_driver(&sc16is7xx_i2c_uart_driver);
        if (ret < 0) {
@@ -1437,6 +1461,7 @@ static void __exit sc16is7xx_exit(void)
 #ifdef CONFIG_SERIAL_SC16IS7XX_SPI
        spi_unregister_driver(&sc16is7xx_spi_uart_driver);
 #endif
+       uart_unregister_driver(&sc16is7xx_uart);
 }
 module_exit(sc16is7xx_exit);