@@ -830,6 +830,13 @@ 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
@@ -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
new file mode 100644
@@ -0,0 +1,136 @@
+// 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>");
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> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- ChangeLog v1->v2: - Use BIT() macro for bitshifted masks. - Use an u8 to keep track of the output value. - Use C99 comment style in the header. --- drivers/gpio/Kconfig | 7 ++ drivers/gpio/Makefile | 1 + drivers/gpio/gpio-gw-pld.c | 136 +++++++++++++++++++++++++++++++++++++ 3 files changed, 144 insertions(+) create mode 100644 drivers/gpio/gpio-gw-pld.c