gpio: Add a Gateworks PLD GPIO driver (2a0b0a57) · Commits · 戴 / test

drivers/gpio/Kconfig

+7 −0

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		@@ -831,6 +831,13 @@ config GPIO_ADNP
		enough to represent all pins, but the driver will assume a
		register layout for 64 pins (8 registers).

		config GPIO_GW_PLD
		tristate "Gateworks PLD GPIO Expander"
		depends on OF_GPIO
		help
		Say yes here to provide access to the Gateworks I2C PLD GPIO
		Expander. This is used at least on the Cambria GW2358-4.

		config GPIO_MAX7300
		tristate "Maxim MAX7300 GPIO expander"
		select GPIO_MAX730X

drivers/gpio/Makefile

+1 −0

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		@@ -55,6 +55,7 @@ obj-$(CONFIG_GPIO_FTGPIO010) += gpio-ftgpio010.o
		obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o
		obj-$(CONFIG_GPIO_GPIO_MM) += gpio-gpio-mm.o
		obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o
		obj-$(CONFIG_GPIO_GW_PLD) += gpio-gw-pld.o
		obj-$(CONFIG_GPIO_HLWD) += gpio-hlwd.o
		obj-$(CONFIG_HTC_EGPIO) += gpio-htc-egpio.o
		obj-$(CONFIG_GPIO_ICH) += gpio-ich.o

drivers/gpio/gpio-gw-pld.c

0 → 100644

+137 −0

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		// SPDX-License-Identifier: GPL-2.0+
		//
		// Gateworks I2C PLD GPIO expander
		//
		// Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org>
		//
		// Based on code and know-how from the OpenWrt driver:
		// Copyright (C) 2009 Gateworks Corporation
		// Authors: Chris Lang, Imre Kaloz

		#include <linux/bits.h>
		#include <linux/kernel.h>
		#include <linux/slab.h>
		#include <linux/gpio/driver.h>
		#include <linux/i2c.h>
		#include <linux/module.h>

		/**
		* struct gw_pld - State container for Gateworks PLD
		* @chip: GPIO chip instance
		* @client: I2C client
		* @out: shadow register for the output bute
		*/
		struct gw_pld {
		struct gpio_chip chip;
		struct i2c_client *client;
		u8 out;
		};

		/*
		* The Gateworks I2C PLD chip only expose one read and one write register.
		* Writing a "one" bit (to match the reset state) lets that pin be used as an
		* input. It is an open-drain model.
		*/
		static int gw_pld_input8(struct gpio_chip *gc, unsigned offset)
		{
		struct gw_pld *gw = gpiochip_get_data(gc);

		gw->out \|= BIT(offset);
		return i2c_smbus_write_byte(gw->client, gw->out);
		}

		static int gw_pld_get8(struct gpio_chip *gc, unsigned offset)
		{
		struct gw_pld *gw = gpiochip_get_data(gc);
		s32 val;

		val = i2c_smbus_read_byte(gw->client);

		return (val < 0) ? 0 : !!(val & BIT(offset));
		}

		static int gw_pld_output8(struct gpio_chip *gc, unsigned offset, int value)
		{
		struct gw_pld *gw = gpiochip_get_data(gc);

		if (value)
		gw->out \|= BIT(offset);
		else
		gw->out &= ~BIT(offset);

		return i2c_smbus_write_byte(gw->client, gw->out);
		}

		static void gw_pld_set8(struct gpio_chip *gc, unsigned offset, int value)
		{
		gw_pld_output8(gc, offset, value);
		}

		static int gw_pld_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct device *dev = &client->dev;
		struct device_node *np = dev->of_node;
		struct gw_pld *gw;
		int ret;

		gw = devm_kzalloc(dev, sizeof(*gw), GFP_KERNEL);
		if (!gw)
		return -ENOMEM;

		gw->chip.base = -1;
		gw->chip.can_sleep = true;
		gw->chip.parent = dev;
		gw->chip.of_node = np;
		gw->chip.owner = THIS_MODULE;
		gw->chip.label = dev_name(dev);
		gw->chip.ngpio = 8;
		gw->chip.direction_input = gw_pld_input8;
		gw->chip.get = gw_pld_get8;
		gw->chip.direction_output = gw_pld_output8;
		gw->chip.set = gw_pld_set8;
		gw->client = client;

		/*
		* The Gateworks I2C PLD chip does not properly send the acknowledge
		* bit at all times, but we can still use the standard i2c_smbus
		* functions by simply ignoring this bit.
		*/
		client->flags \|= I2C_M_IGNORE_NAK;
		gw->out = 0xFF;

		i2c_set_clientdata(client, gw);

		ret = devm_gpiochip_add_data(dev, &gw->chip, gw);
		if (ret)
		return ret;

		dev_info(dev, "registered Gateworks PLD GPIO device\n");

		return 0;
		}

		static const struct i2c_device_id gw_pld_id[] = {
		{ "gw-pld", },
		{ }
		};
		MODULE_DEVICE_TABLE(i2c, gw_pld_id);

		static const struct of_device_id gw_pld_dt_ids[] = {
		{ .compatible = "gateworks,pld-gpio", },
		{ },
		};
		MODULE_DEVICE_TABLE(of, gw_pld_dt_ids);

		static struct i2c_driver gw_pld_driver = {
		.driver = {
		.name = "gw_pld",
		.of_match_table = gw_pld_dt_ids,
		},
		.probe = gw_pld_probe,
		.id_table = gw_pld_id,
		};
		module_i2c_driver(gw_pld_driver);

		MODULE_LICENSE("GPL");
		MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");

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