serial: pl011: Add reg-io-width parameters

Some of the implementations can read only 32 bits because of
the interface limitations of the port they are connected to.
Add a parameter reg-io-width for supporting such platforms.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Link: https://lore.kernel.org/r/20220826120559.2122-3-shubhrajyoti.datta@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 15f0e4d88c5a0346d1506fb409b468cee84664f5..033bf8699540dffc553343489f35634443aae53e 100644 (file)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2777,6 +2777,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
        struct uart_amba_port *uap;
        struct vendor_data *vendor = id->data;
        int portnr, ret;
+       u32 val;
 
        portnr = pl011_find_free_port();
        if (portnr < 0)
@@ -2801,6 +2802,21 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
        uap->port.rs485_supported = pl011_rs485_supported;
        snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
 
+       if (device_property_read_u32(&dev->dev, "reg-io-width", &val) == 0) {
+               switch (val) {
+               case 1:
+                       uap->port.iotype = UPIO_MEM;
+                       break;
+               case 4:
+                       uap->port.iotype = UPIO_MEM32;
+                       break;
+               default:
+                       dev_warn(&dev->dev, "unsupported reg-io-width (%d)\n",
+                                val);
+                       return -EINVAL;
+               }
+       }
+
        ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr);
        if (ret)
                return ret;