Import Turris OS kernel patches

1 files changed, 189 insertions, 0 deletions

diff --git a/nixos/modules/kernel-patches/0077-gpio-gpio-cascade-add-generic-GPIO-cascade.patch b/nixos/modules/kernel-patches/0077-gpio-gpio-cascade-add-generic-GPIO-cascade.patch
new file mode 100644
index 0000000..98dfc24
--- /dev/null
+++ b/nixos/modules/kernel-patches/0077-gpio-gpio-cascade-add-generic-GPIO-cascade.patch
@@ -0,0 +1,189 @@
+From f5105edd6729159f332579da5416aa3a26c84ad6 Mon Sep 17 00:00:00 2001
+From: Mauri Sandberg <maukka@ext.kapsi.fi>
+Date: Thu, 25 Mar 2021 11:48:05 +0200
+Subject: [PATCH 77/96] gpio: gpio-cascade: add generic GPIO cascade
+
+Adds support for building cascades of GPIO lines. That is, it allows
+setups when there is one upstream line and multiple cascaded lines, out
+of which one can be chosen at a time. The status of the upstream line
+can be conveyed to the selected cascaded line or, vice versa, the status
+of the cascaded line can be conveyed to the upstream line.
+
+A multiplexer is being used to select, which cascaded GPIO line is being
+used at any given time.
+
+At the moment only input direction is supported. In future it should be
+possible to add support for output direction, too.
+
+Signed-off-by: Mauri Sandberg <maukka@ext.kapsi.fi>
+Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
+Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
+---
+ drivers/gpio/Kconfig        |  15 +++++
+ drivers/gpio/Makefile       |   1 +
+ drivers/gpio/gpio-cascade.c | 117 ++++++++++++++++++++++++++++++++++++
+ 3 files changed, 133 insertions(+)
+ create mode 100644 drivers/gpio/gpio-cascade.c
+
+diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
+index b01961999ced..b88980948950 100644
+--- a/drivers/gpio/Kconfig
++++ b/drivers/gpio/Kconfig
+@@ -1710,4 +1710,19 @@ config GPIO_SIM
+ 
+ endmenu
+ 
++comment "Other GPIO expanders"
++
++config GPIO_CASCADE
++	tristate "General GPIO cascade"
++	select MULTIPLEXER
++	help
++	  Say yes here to enable support for generic GPIO cascade.
++
++	  This allows building one-to-many cascades of GPIO lines using
++	  different types of multiplexers readily available. At the
++	  moment only input lines are supported.
++
++	  To build the driver as a module choose 'm' and the resulting module
++	  will be called 'gpio-cascade'.
++
+ endif
+diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
+index 14352f6dfe8e..561c060b0d9f 100644
+--- a/drivers/gpio/Makefile
++++ b/drivers/gpio/Makefile
+@@ -44,6 +44,7 @@ obj-$(CONFIG_GPIO_BD9571MWV)		+= gpio-bd9571mwv.o
+ obj-$(CONFIG_GPIO_BRCMSTB)		+= gpio-brcmstb.o
+ obj-$(CONFIG_GPIO_BT8XX)		+= gpio-bt8xx.o
+ obj-$(CONFIG_GPIO_CADENCE)		+= gpio-cadence.o
++obj-$(CONFIG_GPIO_CASCADE)		+= gpio-cascade.o
+ obj-$(CONFIG_GPIO_CLPS711X)		+= gpio-clps711x.o
+ obj-$(CONFIG_GPIO_SNPS_CREG)		+= gpio-creg-snps.o
+ obj-$(CONFIG_GPIO_CRYSTAL_COVE)		+= gpio-crystalcove.o
+diff --git a/drivers/gpio/gpio-cascade.c b/drivers/gpio/gpio-cascade.c
+new file mode 100644
+index 000000000000..5cbda882d79a
+--- /dev/null
++++ b/drivers/gpio/gpio-cascade.c
+@@ -0,0 +1,117 @@
++// SPDX-License-Identifier: GPL-2.0-only
++/*
++ *  A generic GPIO cascade driver
++ *
++ *  Copyright (C) 2021 Mauri Sandberg <maukka@ext.kapsi.fi>
++ *
++ * This allows building cascades of GPIO lines in a manner illustrated
++ * below:
++ *
++ *                 /|---- Cascaded GPIO line 0
++ *  Upstream      | |---- Cascaded GPIO line 1
++ *  GPIO line ----+ | .
++ *                | | .
++ *                 \|---- Cascaded GPIO line n
++ *
++ * A multiplexer is being used to select, which cascaded line is being
++ * addressed at any given time.
++ *
++ * At the moment only input mode is supported due to lack of means for
++ * testing output functionality. At least theoretically output should be
++ * possible with open drain constructions.
++ */
++
++#include <linux/module.h>
++#include <linux/slab.h>
++#include <linux/platform_device.h>
++#include <linux/mux/consumer.h>
++
++#include <linux/gpio/consumer.h>
++#include <linux/gpio/driver.h>
++
++struct gpio_cascade {
++	struct gpio_chip	gpio_chip;
++	struct device		*parent;
++	struct mux_control	*mux_control;
++	struct gpio_desc	*upstream_line;
++};
++
++static struct gpio_cascade *chip_to_cascade(struct gpio_chip *gc)
++{
++	return container_of(gc, struct gpio_cascade, gpio_chip);
++}
++
++static int gpio_cascade_get_direction(struct gpio_chip *gc, unsigned int offset)
++{
++	return GPIO_LINE_DIRECTION_IN;
++}
++
++static int gpio_cascade_get_value(struct gpio_chip *gc, unsigned int offset)
++{
++	struct gpio_cascade *cas = chip_to_cascade(gc);
++	int ret;
++
++	ret = mux_control_select(cas->mux_control, offset);
++	if (ret)
++		return ret;
++
++	ret = gpiod_get_value(cas->upstream_line);
++	mux_control_deselect(cas->mux_control);
++	return ret;
++}
++
++static int gpio_cascade_probe(struct platform_device *pdev)
++{
++	struct device *dev = &pdev->dev;
++	struct gpio_cascade *cas;
++	struct mux_control *mc;
++	struct gpio_desc *upstream;
++	struct gpio_chip *gc;
++
++	cas = devm_kzalloc(dev, sizeof(*cas), GFP_KERNEL);
++	if (!cas)
++		return -ENOMEM;
++
++	mc = devm_mux_control_get(dev, NULL);
++	if (IS_ERR(mc))
++		return dev_err_probe(dev, PTR_ERR(mc), "unable to get mux-control\n");
++
++	cas->mux_control = mc;
++	upstream = devm_gpiod_get(dev, "upstream",  GPIOD_IN);
++	if (IS_ERR(upstream))
++		return dev_err_probe(dev, PTR_ERR(upstream), "unable to claim upstream GPIO line\n");
++
++	cas->upstream_line = upstream;
++	cas->parent = dev;
++
++	gc = &cas->gpio_chip;
++	gc->get = gpio_cascade_get_value;
++	gc->get_direction = gpio_cascade_get_direction;
++	gc->base = -1;
++	gc->ngpio = mux_control_states(mc);
++	gc->label = dev_name(cas->parent);
++	gc->parent = cas->parent;
++	gc->owner = THIS_MODULE;
++
++	platform_set_drvdata(pdev, cas);
++	return devm_gpiochip_add_data(dev, &cas->gpio_chip, NULL);
++}
++
++static const struct of_device_id gpio_cascade_id[] = {
++	{ .compatible = "gpio-cascade" },
++	{ /* sentinel */ }
++};
++MODULE_DEVICE_TABLE(of, gpio_cascade_id);
++
++static struct platform_driver gpio_cascade_driver = {
++	.driver	= {
++		.name		= "gpio-cascade",
++		.of_match_table = gpio_cascade_id,
++	},
++	.probe	= gpio_cascade_probe,
++};
++module_platform_driver(gpio_cascade_driver);
++
++MODULE_AUTHOR("Mauri Sandberg <maukka@ext.kapsi.fi>");
++MODULE_DESCRIPTION("Generic GPIO cascade");
++MODULE_LICENSE("GPL");
+-- 
+2.37.2
+