sc16is7xx: make sure device is in suspend once probed

  Previously sc16is7xx_power was called in order to set the device to a
  low power mode.

  However since SC16IS7XX_EFR_ENABLE_BIT was not set beforehand this
  suspend request had not effect.

  Also, soft-reset the device prior to port initialization. It may
  otherwise be in a state (interrupt pending, fifo not empty) which
  prevents it from sleeping.

Signed-off-by: Florian Vallee <fvallee@eukrea.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index f36e6df..a9d94f7 100644 (file)
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1205,6 +1205,10 @@ static int sc16is7xx_probe(struct device *dev,
        }
 #endif
 
+       /* reset device, purging any pending irq / data */
+       regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG << SC16IS7XX_REG_SHIFT,
+                       SC16IS7XX_IOCONTROL_SRESET_BIT);
+
        for (i = 0; i < devtype->nr_uart; ++i) {
                s->p[i].line            = i;
                /* Initialize port data */
@@ -1234,6 +1238,22 @@ static int sc16is7xx_probe(struct device *dev,
                init_kthread_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
                /* Register port */
                uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
+
+               /* Enable EFR */
+               sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG,
+                                    SC16IS7XX_LCR_CONF_MODE_B);
+
+               regcache_cache_bypass(s->regmap, true);
+
+               /* Enable write access to enhanced features */
+               sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFR_REG,
+                                    SC16IS7XX_EFR_ENABLE_BIT);
+
+               regcache_cache_bypass(s->regmap, false);
+
+               /* Restore access to general registers */
+               sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG, 0x00);
+
                /* Go to suspend mode */
                sc16is7xx_power(&s->p[i].port, 0);
        }