@@ -314,6 +314,7 @@
#define SC16IS7XX_FIFO_SIZE (64)
#define SC16IS7XX_GPIOS_PER_BANK 4
+#define SC16IS7XX_POLL_PERIOD_MS 10
#define SC16IS7XX_RECONF_MD BIT(0)
#define SC16IS7XX_RECONF_IER BIT(1)
#define SC16IS7XX_RECONF_RS485 BIT(2)
@@ -348,6 +349,8 @@ struct sc16is7xx_port {
u8 mctrl_mask;
struct kthread_worker kworker;
struct task_struct *kworker_task;
+ struct kthread_delayed_work poll_work;
+ bool polling;
struct sc16is7xx_one p[];
};
@@ -861,6 +864,18 @@ static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void sc16is7xx_poll_proc(struct kthread_work *ws)
+{
+ struct sc16is7xx_port *s = container_of(ws, struct sc16is7xx_port, poll_work.work);
+
+ /* Reuse standard IRQ handler. Interrupt ID is unused in this context. */
+ sc16is7xx_irq(0, s);
+
+ /* Setup delay based on SC16IS7XX_POLL_PERIOD_MS */
+ kthread_queue_delayed_work(&s->kworker, &s->poll_work,
+ msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS));
+}
+
static void sc16is7xx_tx_proc(struct kthread_work *ws)
{
struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
@@ -1149,6 +1164,7 @@ static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios *termi
static int sc16is7xx_startup(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
+ struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned int val;
unsigned long flags;
@@ -1211,6 +1227,10 @@ static int sc16is7xx_startup(struct uart_port *port)
sc16is7xx_enable_ms(port);
uart_port_unlock_irqrestore(port, flags);
+ if (s->polling)
+ kthread_queue_delayed_work(&s->kworker, &s->poll_work,
+ msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS));
+
return 0;
}
@@ -1232,6 +1252,9 @@ static void sc16is7xx_shutdown(struct uart_port *port)
sc16is7xx_power(port, 0);
+ if (s->polling)
+ kthread_cancel_delayed_work_sync(&s->poll_work);
+
kthread_flush_worker(&s->kworker);
}
@@ -1538,6 +1561,11 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
/* Always ask for fixed clock rate from a property. */
device_property_read_u32(dev, "clock-frequency", &uartclk);
+ s->polling = (irq <= 0);
+ if (s->polling)
+ dev_dbg(dev,
+ "No interrupt pin definition, falling back to polling mode\n");
+
s->clk = devm_clk_get_optional(dev, NULL);
if (IS_ERR(s->clk))
return PTR_ERR(s->clk);
@@ -1665,6 +1693,12 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
goto out_ports;
#endif
+ if (s->polling) {
+ /* Initialize kernel thread for polling */
+ kthread_init_delayed_work(&s->poll_work, sc16is7xx_poll_proc);
+ return 0;
+ }
+
/*
* Setup interrupt. We first try to acquire the IRQ line as level IRQ.
* If that succeeds, we can allow sharing the interrupt as well.
@@ -1724,6 +1758,9 @@ void sc16is7xx_remove(struct device *dev)
sc16is7xx_power(&s->p[i].port, 0);
}
+ if (s->polling)
+ kthread_cancel_delayed_work_sync(&s->poll_work);
+
kthread_flush_worker(&s->kworker);
kthread_stop(s->kworker_task);
Fall back to polling mode if no interrupt is configured because there is no possibility to connect the interrupt pin. If "interrupts" property is missing in devicetree the driver uses a delayed worker to pull the state of interrupt status registers. Signed-off-by: Andre Werner <andre.werner@systec-electronic.com> --- V2: - Change warning for polling mode to debug log entry - Correct typo: Resuse -> Reuse - Format define with missing tabs for SC16IS7XX_POLL_PERIOD - Format struct declaration sc16is7xx_one_config with missing tabs for polling and shutdown - Adapt dtbinding with new polling feature V3: - Use suffix with units and drop a comment SC16IS7XX_POLL_PERIOD_MS. Sorry for that miss. - Make Kernel lowercase. V4: - Reword commit messages for better understanding. - Remove 'shutdown' property for canceling delayed worker. - Rename worker function: sc16is7xx_transmission_poll -> sc16is7xx_poll_proc - Unify argument for worker functions: kthread_work *work -> kthread_work *ws V5: - Replace of_property check with IRQ number check to set polling property. This will add support for usage without device tree definitions. Thanks for that advice. - Add blank line es requested. V6: - Use polling mode for IRQ numbers <= 0 which encounter no valid IRQ were found/defined. --- drivers/tty/serial/sc16is7xx.c | 37 ++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)