From 856ed97af5cfcfdc73cc4178d9670122bca52f6b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marek=20Beh=C3=BAn?= Date: Mon, 12 Aug 2019 18:11:17 +0200 Subject: [PATCH] drivers: gpio: Add support for GPIOs over Moxtet bus MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds support for interpreting the input and output bits of one device on Moxtet bus as GPIOs. This is needed for example by the SFP cage module of Turris Mox. Link: https://lore.kernel.org/r/20190812161118.21476-5-marek.behun@nic.cz Signed-off-by: Marek Behún Reviewed-by: Linus Walleij Signed-off-by: Arnd Bergmann --- MAINTAINERS | 1 + drivers/gpio/Kconfig | 9 ++ drivers/gpio/Makefile | 1 + drivers/gpio/gpio-moxtet.c | 179 +++++++++++++++++++++++++++++++++++++ 4 files changed, 190 insertions(+) create mode 100644 drivers/gpio/gpio-moxtet.c diff --git a/MAINTAINERS b/MAINTAINERS index 1869e83f514a..a71ab252ad7e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1635,6 +1635,7 @@ F: Documentation/ABI/testing/sysfs-bus-moxtet-devices F: Documentation/devicetree/bindings/bus/moxtet.txt F: include/linux/moxtet.h F: drivers/bus/moxtet.c +F: drivers/gpio/gpio-moxtet.c ARM/EBSA110 MACHINE SUPPORT M: Russell King diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index bb13c266c329..eef4886a3bc3 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1445,6 +1445,15 @@ config GPIO_XRA1403 help GPIO driver for EXAR XRA1403 16-bit SPI-based GPIO expander. +config GPIO_MOXTET + tristate "Turris Mox Moxtet bus GPIO expander" + depends on MOXTET + help + Say yes here if you are building for the Turris Mox router. + This is the driver needed for configuring the GPIOs via the Moxtet + bus. For example the Mox module with SFP cage needs this driver + so that phylink can use corresponding GPIOs. + endmenu menu "USB GPIO expanders" diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index a4e91175c708..2e10caec23ae 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_GPIO_ML_IOH) += gpio-ml-ioh.o obj-$(CONFIG_GPIO_MLXBF) += gpio-mlxbf.o obj-$(CONFIG_GPIO_MM_LANTIQ) += gpio-mm-lantiq.o obj-$(CONFIG_GPIO_MOCKUP) += gpio-mockup.o +obj-$(CONFIG_GPIO_MOXTET) += gpio-moxtet.o obj-$(CONFIG_GPIO_MPC5200) += gpio-mpc5200.o obj-$(CONFIG_GPIO_MPC8XXX) += gpio-mpc8xxx.o obj-$(CONFIG_GPIO_MSIC) += gpio-msic.o diff --git a/drivers/gpio/gpio-moxtet.c b/drivers/gpio/gpio-moxtet.c new file mode 100644 index 000000000000..3fd729994a38 --- /dev/null +++ b/drivers/gpio/gpio-moxtet.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Turris Mox Moxtet GPIO expander + * + * Copyright (C) 2018 Marek Behun + */ + +#include +#include +#include +#include + +#define MOXTET_GPIO_NGPIOS 12 +#define MOXTET_GPIO_INPUTS 4 + +struct moxtet_gpio_desc { + u16 in_mask; + u16 out_mask; +}; + +static const struct moxtet_gpio_desc descs[] = { + [TURRIS_MOX_MODULE_SFP] = { + .in_mask = GENMASK(2, 0), + .out_mask = GENMASK(5, 4), + }, +}; + +struct moxtet_gpio_chip { + struct device *dev; + struct gpio_chip gpio_chip; + const struct moxtet_gpio_desc *desc; +}; + +static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + int ret; + + if (chip->desc->in_mask & BIT(offset)) { + ret = moxtet_device_read(chip->dev); + } else if (chip->desc->out_mask & BIT(offset)) { + ret = moxtet_device_written(chip->dev); + if (ret >= 0) + ret <<= MOXTET_GPIO_INPUTS; + } else { + return -EINVAL; + } + + if (ret < 0) + return ret; + + return !!(ret & BIT(offset)); +} + +static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset, + int val) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + int state; + + state = moxtet_device_written(chip->dev); + if (state < 0) + return; + + offset -= MOXTET_GPIO_INPUTS; + + if (val) + state |= BIT(offset); + else + state &= ~BIT(offset); + + moxtet_device_write(chip->dev, state); +} + +static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + + /* All lines are hard wired to be either input or output, not both. */ + if (chip->desc->in_mask & BIT(offset)) + return 1; + else if (chip->desc->out_mask & BIT(offset)) + return 0; + else + return -EINVAL; +} + +static int moxtet_gpio_direction_input(struct gpio_chip *gc, + unsigned int offset) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + + if (chip->desc->in_mask & BIT(offset)) + return 0; + else if (chip->desc->out_mask & BIT(offset)) + return -ENOTSUPP; + else + return -EINVAL; +} + +static int moxtet_gpio_direction_output(struct gpio_chip *gc, + unsigned int offset, int val) +{ + struct moxtet_gpio_chip *chip = gpiochip_get_data(gc); + + if (chip->desc->out_mask & BIT(offset)) + moxtet_gpio_set_value(gc, offset, val); + else if (chip->desc->in_mask & BIT(offset)) + return -ENOTSUPP; + else + return -EINVAL; + + return 0; +} + +static int moxtet_gpio_probe(struct device *dev) +{ + struct moxtet_gpio_chip *chip; + struct device_node *nc = dev->of_node; + int id; + + id = to_moxtet_device(dev)->id; + + if (id >= ARRAY_SIZE(descs)) { + dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n", + nc, id); + return -ENOTSUPP; + } + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + chip->dev = dev; + chip->gpio_chip.parent = dev; + chip->desc = &descs[id]; + + dev_set_drvdata(dev, chip); + + chip->gpio_chip.label = dev_name(dev); + chip->gpio_chip.get_direction = moxtet_gpio_get_direction; + chip->gpio_chip.direction_input = moxtet_gpio_direction_input; + chip->gpio_chip.direction_output = moxtet_gpio_direction_output; + chip->gpio_chip.get = moxtet_gpio_get_value; + chip->gpio_chip.set = moxtet_gpio_set_value; + chip->gpio_chip.base = -1; + + chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS; + + chip->gpio_chip.can_sleep = true; + chip->gpio_chip.owner = THIS_MODULE; + + return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip); +} + +static const struct of_device_id moxtet_gpio_dt_ids[] = { + { .compatible = "cznic,moxtet-gpio", }, + {}, +}; +MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids); + +static const enum turris_mox_module_id moxtet_gpio_module_table[] = { + TURRIS_MOX_MODULE_SFP, + 0, +}; + +static struct moxtet_driver moxtet_gpio_driver = { + .driver = { + .name = "moxtet-gpio", + .of_match_table = moxtet_gpio_dt_ids, + .probe = moxtet_gpio_probe, + }, + .id_table = moxtet_gpio_module_table, +}; +module_moxtet_driver(moxtet_gpio_driver); + +MODULE_AUTHOR("Marek Behun "); +MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander"); +MODULE_LICENSE("GPL v2");