USB: serial: cp210x: support all gpios on CP2102N QFN28 package

The QFN28 package version of the CP2102N has three additional gpio pins.
Add support for these.

Signed-off-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index c0777a3..336a3c0 100644 (file)
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1574,12 +1574,6 @@ static int cp2102n_gpioconf_init(struct usb_serial *serial)
        if (config_version != 0x01)
                return -ENOTSUPP;
 
-       /*
-        * We only support 4 GPIOs even on the QFN28 package, because
-        * config locations of GPIOs 4-6 determined using reverse
-        * engineering revealed conflicting offsets with other
-        * documented functions. So we'll just play it safe for now.
-        */
        priv->gc.ngpio = 4;
 
        /*
@@ -1594,6 +1588,19 @@ static int cp2102n_gpioconf_init(struct usb_serial *serial)
        /* 0 indicates GPIO mode, 1 is alternate function */
        priv->gpio_altfunc = (gpio_ctrl >> 2) & 0x0f;
 
+       if (priv->partnum == CP210X_PARTNUM_CP2102N_QFN28) {
+               /*
+                * For the QFN28 package, GPIO4-6 are controlled by
+                * the low three bits of the mode/latch fields.
+                * Contrary to the document linked above, the bits for
+                * the SUSPEND pins are elsewhere.  No alternate
+                * function is available for these pins.
+                */
+               priv->gc.ngpio = 7;
+               gpio_latch |= (gpio_rst_latch & 7) << 4;
+               priv->gpio_pushpull |= (gpio_pushpull & 7) << 4;
+       }
+
        /*
         * The CP2102N does not strictly has input and output pin modes,
         * it only knows open-drain and push-pull modes which is set at