[PATCH 4.14 21/33] NFC: nfcmrvl: fix gpio-handling regression

From: Greg Kroah-Hartman
Date: Thu Aug 08 2019 - 15:11:02 EST


From: Johan Hovold <johan@xxxxxxxxxx>

[ Upstream commit c3953a3c2d3175d2f9f0304c9a1ba89e7743c5e4 ]

Fix two reset-gpio sanity checks which were never converted to use
gpio_is_valid(), and make sure to use -EINVAL to indicate a missing
reset line also for the UART-driver module parameter and for the USB
driver.

This specifically prevents the UART and USB drivers from incidentally
trying to request and use gpio 0, and also avoids triggering a WARN() in
gpio_to_desc() during probe when no valid reset line has been specified.

Fixes: e33a3f84f88f ("NFC: nfcmrvl: allow gpio 0 for reset signalling")
Reported-by: syzbot+cf35b76f35e068a1107f@xxxxxxxxxxxxxxxxxxxxxxxxx
Tested-by: syzbot+cf35b76f35e068a1107f@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/nfc/nfcmrvl/main.c | 4 ++--
drivers/nfc/nfcmrvl/uart.c | 4 ++--
drivers/nfc/nfcmrvl/usb.c | 1 +
3 files changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/nfc/nfcmrvl/main.c
+++ b/drivers/nfc/nfcmrvl/main.c
@@ -244,7 +244,7 @@ void nfcmrvl_chip_reset(struct nfcmrvl_p
/* Reset possible fault of previous session */
clear_bit(NFCMRVL_PHY_ERROR, &priv->flags);

- if (priv->config.reset_n_io) {
+ if (gpio_is_valid(priv->config.reset_n_io)) {
nfc_info(priv->dev, "reset the chip\n");
gpio_set_value(priv->config.reset_n_io, 0);
usleep_range(5000, 10000);
@@ -255,7 +255,7 @@ void nfcmrvl_chip_reset(struct nfcmrvl_p

void nfcmrvl_chip_halt(struct nfcmrvl_private *priv)
{
- if (priv->config.reset_n_io)
+ if (gpio_is_valid(priv->config.reset_n_io))
gpio_set_value(priv->config.reset_n_io, 0);
}

--- a/drivers/nfc/nfcmrvl/uart.c
+++ b/drivers/nfc/nfcmrvl/uart.c
@@ -26,7 +26,7 @@
static unsigned int hci_muxed;
static unsigned int flow_control;
static unsigned int break_control;
-static unsigned int reset_n_io;
+static int reset_n_io = -EINVAL;

/*
** NFCMRVL NCI OPS
@@ -231,5 +231,5 @@ MODULE_PARM_DESC(break_control, "Tell if
module_param(hci_muxed, uint, 0);
MODULE_PARM_DESC(hci_muxed, "Tell if transport is muxed in HCI one.");

-module_param(reset_n_io, uint, 0);
+module_param(reset_n_io, int, 0);
MODULE_PARM_DESC(reset_n_io, "GPIO that is wired to RESET_N signal.");
--- a/drivers/nfc/nfcmrvl/usb.c
+++ b/drivers/nfc/nfcmrvl/usb.c
@@ -304,6 +304,7 @@ static int nfcmrvl_probe(struct usb_inte

/* No configuration for USB */
memset(&config, 0, sizeof(config));
+ config.reset_n_io = -EINVAL;

nfc_info(&udev->dev, "intf %p id %p\n", intf, id);