tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
gpio: Add a Gateworks PLD GPIO driver
This adds a driver for Gateworks PLD GPIO, that exist in
two instances on the Gateworks Cambria GW2358-4 router
platform at least.
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
+145
+7
drivers/gpio/Kconfig
+7
drivers/gpio/Kconfig
···
831
831
enough to represent all pins, but the driver will assume a
832
832
register layout for 64 pins (8 registers).
833
833
834
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config GPIO_GW_PLD
835
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tristate "Gateworks PLD GPIO Expander"
836
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depends on OF_GPIO
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help
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Say yes here to provide access to the Gateworks I2C PLD GPIO
839
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Expander. This is used at least on the Cambria GW2358-4.
840
+
834
841
config GPIO_MAX7300
835
842
tristate "Maxim MAX7300 GPIO expander"
836
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select GPIO_MAX730X
+1
drivers/gpio/Makefile
+1
drivers/gpio/Makefile
···
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obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o
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obj-$(CONFIG_GPIO_GPIO_MM) += gpio-gpio-mm.o
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obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o
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obj-$(CONFIG_GPIO_GW_PLD) += gpio-gw-pld.o
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obj-$(CONFIG_GPIO_HLWD) += gpio-hlwd.o
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obj-$(CONFIG_HTC_EGPIO) += gpio-htc-egpio.o
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obj-$(CONFIG_GPIO_ICH) += gpio-ich.o
+137
drivers/gpio/gpio-gw-pld.c
+137
drivers/gpio/gpio-gw-pld.c
···
1
+
// SPDX-License-Identifier: GPL-2.0+
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+
//
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// Gateworks I2C PLD GPIO expander
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//
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// Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org>
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//
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// Based on code and know-how from the OpenWrt driver:
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// Copyright (C) 2009 Gateworks Corporation
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// Authors: Chris Lang, Imre Kaloz
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+
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#include <linux/bits.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/gpio/driver.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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+
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/**
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* struct gw_pld - State container for Gateworks PLD
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* @chip: GPIO chip instance
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* @client: I2C client
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* @out: shadow register for the output bute
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*/
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struct gw_pld {
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struct gpio_chip chip;
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struct i2c_client *client;
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u8 out;
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};
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+
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/*
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* The Gateworks I2C PLD chip only expose one read and one write register.
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* Writing a "one" bit (to match the reset state) lets that pin be used as an
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* input. It is an open-drain model.
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*/
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static int gw_pld_input8(struct gpio_chip *gc, unsigned offset)
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{
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struct gw_pld *gw = gpiochip_get_data(gc);
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+
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gw->out |= BIT(offset);
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return i2c_smbus_write_byte(gw->client, gw->out);
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}
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+
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static int gw_pld_get8(struct gpio_chip *gc, unsigned offset)
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{
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struct gw_pld *gw = gpiochip_get_data(gc);
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s32 val;
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+
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val = i2c_smbus_read_byte(gw->client);
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return (val < 0) ? 0 : !!(val & BIT(offset));
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}
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+
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static int gw_pld_output8(struct gpio_chip *gc, unsigned offset, int value)
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{
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struct gw_pld *gw = gpiochip_get_data(gc);
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+
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if (value)
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gw->out |= BIT(offset);
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else
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gw->out &= ~BIT(offset);
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return i2c_smbus_write_byte(gw->client, gw->out);
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}
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+
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static void gw_pld_set8(struct gpio_chip *gc, unsigned offset, int value)
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{
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gw_pld_output8(gc, offset, value);
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}
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+
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static int gw_pld_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct device_node *np = dev->of_node;
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struct gw_pld *gw;
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int ret;
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+
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gw = devm_kzalloc(dev, sizeof(*gw), GFP_KERNEL);
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if (!gw)
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return -ENOMEM;
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+
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gw->chip.base = -1;
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gw->chip.can_sleep = true;
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gw->chip.parent = dev;
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gw->chip.of_node = np;
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gw->chip.owner = THIS_MODULE;
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gw->chip.label = dev_name(dev);
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gw->chip.ngpio = 8;
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gw->chip.direction_input = gw_pld_input8;
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gw->chip.get = gw_pld_get8;
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gw->chip.direction_output = gw_pld_output8;
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gw->chip.set = gw_pld_set8;
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gw->client = client;
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+
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/*
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* The Gateworks I2C PLD chip does not properly send the acknowledge
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* bit at all times, but we can still use the standard i2c_smbus
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* functions by simply ignoring this bit.
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*/
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client->flags |= I2C_M_IGNORE_NAK;
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gw->out = 0xFF;
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i2c_set_clientdata(client, gw);
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+
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ret = devm_gpiochip_add_data(dev, &gw->chip, gw);
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if (ret)
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return ret;
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dev_info(dev, "registered Gateworks PLD GPIO device\n");
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return 0;
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}
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+
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static const struct i2c_device_id gw_pld_id[] = {
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{ "gw-pld", },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, gw_pld_id);
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+
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static const struct of_device_id gw_pld_dt_ids[] = {
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{ .compatible = "gateworks,pld-gpio", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, gw_pld_dt_ids);
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+
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static struct i2c_driver gw_pld_driver = {
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.driver = {
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.name = "gw_pld",
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.of_match_table = gw_pld_dt_ids,
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},
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.probe = gw_pld_probe,
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.id_table = gw_pld_id,
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};
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module_i2c_driver(gw_pld_driver);
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+
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");