[PATCH 5.4 58/84] USB: serial: cp210x: fix alternate function for CP2102N QFN20

Greg Kroah-Hartman
2021-06-14T11:00:49Z

From: Stefan Agner <stefan@agner.ch>

commit 6f7ec77cc8b64ff5037c1945e4650c65c458037d upstream.

The QFN20 part has a different GPIO/port function assignment. The
configuration struct bit field ordered as TX/RX/RS485/WAKEUP/CLK
which exactly matches GPIO0-3 for QFN24/28. However, QFN20 has a
different GPIO to primary function assignment.

Special case QFN20 to follow to properly detect which GPIOs are
available.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Link: https://lore.kernel.org/r/51830b2b24118eb0f77c5c9ac64ffb2f519dbb1d.1622218300.git.stefan@agner.ch
Fixes: c8acfe0aadbe ("USB: serial: cp210x: implement GPIO support for CP2102N")
Cc: stable@vger.kernel.org # 4.19
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/serial/cp210x.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -507,6 +507,12 @@ struct cp210x_single_port_config {
#define CP210X_2NCONFIG_GPIO_RSTLATCH_IDX 587
#define CP210X_2NCONFIG_GPIO_CONTROL_IDX 600

+/* CP2102N QFN20 port configuration values */
+#define CP2102N_QFN20_GPIO2_TXLED_MODE BIT(2)
+#define CP2102N_QFN20_GPIO3_RXLED_MODE BIT(3)
+#define CP2102N_QFN20_GPIO1_RS485_MODE BIT(4)
+#define CP2102N_QFN20_GPIO0_CLK_MODE BIT(6)
+
/* CP210X_VENDOR_SPECIFIC, CP210X_WRITE_LATCH call writes these 0x2 bytes. */
struct cp210x_gpio_write {
u8 mask;
@@ -1691,7 +1697,19 @@ static int cp2102n_gpioconf_init(struct
priv->gpio_pushpull = (gpio_pushpull >> 3) & 0x0f;

/* 0 indicates GPIO mode, 1 is alternate function */
- priv->gpio_altfunc = (gpio_ctrl >> 2) & 0x0f;
+ if (priv->partnum == CP210X_PARTNUM_CP2102N_QFN20) {
+ /* QFN20 is special... */
+ if (gpio_ctrl & CP2102N_QFN20_GPIO0_CLK_MODE) /* GPIO 0 */
+ priv->gpio_altfunc |= BIT(0);
+ if (gpio_ctrl & CP2102N_QFN20_GPIO1_RS485_MODE) /* GPIO 1 */
+ priv->gpio_altfunc |= BIT(1);
+ if (gpio_ctrl & CP2102N_QFN20_GPIO2_TXLED_MODE) /* GPIO 2 */
+ priv->gpio_altfunc |= BIT(2);
+ if (gpio_ctrl & CP2102N_QFN20_GPIO3_RXLED_MODE) /* GPIO 3 */
+ priv->gpio_altfunc |= BIT(3);
+ } else {
+ priv->gpio_altfunc = (gpio_ctrl >> 2) & 0x0f;
+ }

if (priv->partnum == CP210X_PARTNUM_CP2102N_QFN28) {
/*