diff options
Diffstat (limited to 'drivers/serial/serial_bcm283x_mu.c')
| -rw-r--r-- | drivers/serial/serial_bcm283x_mu.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c index c6132b4463..40029fadbc 100644 --- a/drivers/serial/serial_bcm283x_mu.c +++ b/drivers/serial/serial_bcm283x_mu.c @@ -19,9 +19,11 @@ #include <dm.h> #include <errno.h> #include <watchdog.h> +#include <asm/gpio.h> #include <asm/io.h> #include <serial.h> #include <dm/platform_data/serial_bcm283x_mu.h> +#include <dm/pinctrl.h> #include <linux/compiler.h> struct bcm283x_mu_regs { @@ -136,11 +138,37 @@ static const struct udevice_id bcm283x_mu_serial_id[] = { {} }; +/* + * Check if this serial device is muxed + * + * The serial device will only work properly if it has been muxed to the serial + * pins by firmware. Check whether that happened here. + * + * @return true if serial device is muxed, false if not + */ +static bool bcm283x_is_serial_muxed(void) +{ + int serial_gpio = 15; + struct udevice *dev; + + if (uclass_first_device(UCLASS_PINCTRL, &dev) || !dev) + return false; + + if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT5) + return false; + + return true; +} + static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev) { struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); fdt_addr_t addr; + /* Don't spawn the device if it's not muxed */ + if (!bcm283x_is_serial_muxed()) + return -ENODEV; + addr = devfdt_get_addr(dev); if (addr == FDT_ADDR_T_NONE) return -EINVAL; |