tty: amba-pl011: probe ZTE device from AMBA bus with a pseudo-ID

There is no Peripheral Identification Registers on ZTE PL011 device, so
although the driver amba-pl011 is ready to work for ZTE device, the
device cannot be probed by the driver at all.

With arm,primecell-periphid DT bindings (bindings/arm/primecell.txt) in
place, it should be the cleanest the way to use a pseudo-ID to probe the
device from AMBA bus.  We create an unofficial vendor number
AMBA_VENDOR_LINUX, which will practically never become an official
vendor ID, and takes Configuration, Revision number, and Part number as
input to compose a pseudo-ID for ZTE device.

Also, since we start using vendor_zte to probe ZTE device, the
__maybe_unused for vendor_zte is removed.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
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 055fe27..0b78b04 100644 (file)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -209,7 +209,7 @@ static unsigned int get_fifosize_zte(struct amba_device *dev)
        return 16;
 }
 
-static struct vendor_data vendor_zte __maybe_unused = {
+static struct vendor_data vendor_zte = {
        .reg_offset             = pl011_zte_offsets,
        .access_32b             = true,
        .ifls                   = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
@@ -2652,6 +2652,11 @@ static struct amba_id pl011_ids[] = {
                .mask   = 0x00ffffff,
                .data   = &vendor_st,
        },
+       {
+               .id     = AMBA_LINUX_ID(0x00, 0x1, 0xffe),
+               .mask   = 0x00ffffff,
+               .data   = &vendor_zte,
+       },
        { 0, 0 },
 };
 

diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
index 3d8dcdd..d143c13 100644 (file)
--- a/include/linux/amba/bus.h
+++ b/include/linux/amba/bus.h
@@ -53,8 +53,14 @@ enum amba_vendor {
        AMBA_VENDOR_ST = 0x80,
        AMBA_VENDOR_QCOM = 0x51,
        AMBA_VENDOR_LSI = 0xb6,
+       AMBA_VENDOR_LINUX = 0xfe,       /* This value is not official */
 };
 
+/* This is used to generate pseudo-ID for AMBA device */
+#define AMBA_LINUX_ID(conf, rev, part) \
+       (((conf) & 0xff) << 24 | ((rev) & 0xf) << 20 | \
+       AMBA_VENDOR_LINUX << 12 | ((part) & 0xfff))
+
 extern struct bus_type amba_bustype;
 
 #define to_amba_device(d)      container_of(d, struct amba_device, dev)