4.14-stable patches

added patches:
	serial-sc16is7xx-fix-bug-when-first-setting-gpio-direction.patch

diff --git a/queue-4.14/serial-sc16is7xx-fix-bug-when-first-setting-gpio-direction.patch b/queue-4.14/serial-sc16is7xx-fix-bug-when-first-setting-gpio-direction.patch
new file mode 100644 (file)
index 0000000..663324d
--- /dev/null
+++ b/queue-4.14/serial-sc16is7xx-fix-bug-when-first-setting-gpio-direction.patch
@@ -0,0 +1,59 @@
+From 9baeea723c0fb9c3ba9a336369f758ed9bc6831d Mon Sep 17 00:00:00 2001
+From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
+Date: Mon, 7 Aug 2023 17:45:55 -0400
+Subject: serial: sc16is7xx: fix bug when first setting GPIO direction
+
+From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
+
+commit 9baeea723c0fb9c3ba9a336369f758ed9bc6831d upstream.
+
+When configuring a pin as an output pin with a value of logic 0, we
+end up as having a value of logic 1 on the output pin. Setting a
+logic 0 a second time (or more) after that will correctly output a
+logic 0 on the output pin.
+
+By default, all GPIO pins are configured as inputs. When we enter
+sc16is7xx_gpio_direction_output() for the first time, we first set the
+desired value in IOSTATE, and then we configure the pin as an output.
+The datasheet states that writing to IOSTATE register will trigger a
+transfer of the value to the I/O pin configured as output, so if the
+pin is configured as an input, nothing will be transferred.
+
+Therefore, set the direction first in IODIR, and then set the desired
+value in IOSTATE.
+
+This is what is done in NXP application note AN10587.
+
+Fixes: dfeae619d781 ("serial: sc16is7xx")
+Cc: stable@vger.kernel.org
+Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
+Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com>
+Tested-by: Lech Perczak <lech.perczak@camlingroup.com>
+Link: https://lore.kernel.org/r/20230807214556.540627-6-hugo@hugovil.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/sc16is7xx.c |   11 ++++++++++-
+ 1 file changed, 10 insertions(+), 1 deletion(-)
+
+--- a/drivers/tty/serial/sc16is7xx.c
++++ b/drivers/tty/serial/sc16is7xx.c
+@@ -1171,9 +1171,18 @@ static int sc16is7xx_gpio_direction_outp
+               state |= BIT(offset);
+       else
+               state &= ~BIT(offset);
+-      sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state);
++
++      /*
++       * If we write IOSTATE first, and then IODIR, the output value is not
++       * transferred to the corresponding I/O pin.
++       * The datasheet states that each register bit will be transferred to
++       * the corresponding I/O pin programmed as output when writing to
++       * IOSTATE. Therefore, configure direction first with IODIR, and then
++       * set value after with IOSTATE.
++       */
+       sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
+                             BIT(offset));
++      sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state);
+ 
+       return 0;
+ }

diff --git a/queue-4.14/series b/queue-4.14/series
index f66aa9af8634a0fbd2e5d36492f080d6bcde3fd7..b298b883662d5f55f358758ede0d65be2ccb1f31 100644 (file)
--- a/queue-4.14/series
+++ b/queue-4.14/series
@@ -6,3 +6,4 @@ usb-serial-option-add-quectel-em05g-variant-0x030e.patch
 usb-serial-option-add-foxconn-t99w368-t99w373-product.patch
 hid-wacom-remove-the-battery-when-the-ekr-is-off.patch
 bluetooth-btsdio-fix-use-after-free-bug-in-btsdio_remove-due-to-race-condition.patch
+serial-sc16is7xx-fix-bug-when-first-setting-gpio-direction.patch