diff options
| -rw-r--r-- | drivers/tty/serial/sc16is7xx.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 7d98367d6e83..8fee0e8b851f 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1172,6 +1172,7 @@ static int sc16is7xx_probe(struct device *dev, { struct sched_param sched_param = { .sched_priority = MAX_RT_PRIO / 2 }; unsigned long freq = 0, *pfreq = dev_get_platdata(dev); + unsigned int val; u32 uartclk = 0; int i, ret; struct sc16is7xx_port *s; @@ -1179,6 +1180,16 @@ static int sc16is7xx_probe(struct device *dev, if (IS_ERR(regmap)) return PTR_ERR(regmap); + /* + * This device does not have an identification register that would + * tell us if we are really connected to the correct device. + * The best we can do is to check if communication is at all possible. + */ + ret = regmap_read(regmap, + SC16IS7XX_LSR_REG << SC16IS7XX_REG_SHIFT, &val); + if (ret < 0) + return ret; + /* Alloc port structure */ s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL); if (!s) { |