From: Eric Anholt <[email protected]> This commit needs to be split up and cleaned up. Also we should add interrupt support before pushing upstream.
Signed-off-by: Eric Anholt <[email protected]> Conflicts: arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts --- arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts | 16 ++ drivers/gpio/Kconfig | 6 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-fxl6408.c | 244 +++++++++++++++++++++++ 4 files changed, 267 insertions(+) create mode 100644 drivers/gpio/gpio-fxl6408.c diff --git a/arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts b/arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts index 099dd48d..4bc191e 100644 --- a/arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts +++ b/arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts @@ -39,3 +39,19 @@ &hdmi { hpd-gpios = <&gpio 46 GPIO_ACTIVE_LOW>; }; + +/* Connect the GPIO expander to I2C1 */ +&i2c0 { + pinctrl-names = "default"; + pinctrl-0 = <&i2c0_gpio44>; + + gpio_expander: gpio@43 { + gpio-controller; + #gpio-cells = <2>; + reg = <0x43>; + compatible = "fcs,fxl6408"; + }; +}; + +bt { +}; diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 48da857..34056cd 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -665,6 +665,12 @@ config GPIO_ADNP enough to represent all pins, but the driver will assume a register layout for 64 pins (8 registers). +config GPIO_FXL6408 + tristate "FXL6408 I2C GPIO expander" + help + This option enables support for 8 GPIOs found + on the Fairchild Semiconductor FXL6408. + config GPIO_MAX7300 tristate "Maxim MAX7300 GPIO expander" select GPIO_MAX730X diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 991598e..59a25ef 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -43,6 +43,7 @@ obj-$(CONFIG_GPIO_EM) += gpio-em.o obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o obj-$(CONFIG_GPIO_ETRAXFS) += gpio-etraxfs.o obj-$(CONFIG_GPIO_F7188X) += gpio-f7188x.o +obj-$(CONFIG_GPIO_FXL6408) += gpio-fxl6408.o obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o obj-$(CONFIG_GPIO_ICH) += gpio-ich.o diff --git a/drivers/gpio/gpio-fxl6408.c b/drivers/gpio/gpio-fxl6408.c new file mode 100644 index 0000000..02b2816 --- /dev/null +++ b/drivers/gpio/gpio-fxl6408.c @@ -0,0 +1,244 @@ +/* + * Copyright (C) 2016 Broadcom Limited. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + */ + +/** + * DOC: FXL6408 I2C to GPIO expander. + * + * This chip has has 8 GPIO lines out of it, and is controlled by an + * I2C bus (a pair of lines), providing 4x expansion of GPIO lines. + * It also provides an interrupt line out for notifying of + * statechanges. + * + * Any preconfigured state will be left in place until the GPIO lines + * get activated. At power on, everything is treated as an input. + * + * Documentation can be found at: + * https://www.fairchildsemi.com/datasheets/FX/FXL6408.pdf + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/gpio.h> +#include <linux/i2c.h> +#include <linux/slab.h> +#include <linux/of_platform.h> + +#define FXL6408_DEVICE_ID 0x01 +# define FXL6408_RST_INT BIT(1) +# define FXL6408_SW_RST BIT(0) + +/* Bits set here indicate that the GPIO is an output. */ +#define FXL6408_IO_DIR 0x03 +/* Bits set here, when the corresponding bit of IO_DIR is set, drive + * the output high instead of low. + */ +#define FXL6408_OUTPUT 0x05 +/* Bits here make the output High-Z, instead of the OUTPUT value. */ +#define FXL6408_OUTPUT_HIGH_Z 0x07 +/* Bits here define the expected input state of the GPIO. + * INTERRUPT_STAT bits will be set when the INPUT transitions away + * from this value. + */ +#define FXL6408_INPUT_DEFAULT_STATE 0x09 +/* Bits here enable either pull up or pull down according to + * FXL6408_PULL_DOWN. + */ +#define FXL6408_PULL_ENABLE 0x0b +/* Bits set here (when the corresponding PULL_ENABLE is set) enable a + * pull-up instead of a pull-down. + */ +#define FXL6408_PULL_UP 0x0d +/* Returns the current status (1 = HIGH) of the input pins. */ +#define FXL6408_INPUT_STATUS 0x0f +/* Mask of pins which can generate interrupts. */ +#define FXL6408_INTERRUPT_MASK 0x11 +/* Mask of pins which have generated an interrupt. Cleared on read. */ +#define FXL6408_INTERRUPT_STAT 0x13 + +struct fxl6408_chip { + struct gpio_chip gpio_chip; + struct i2c_client *client; + struct mutex i2c_lock; + + /* Caches of register values so we don't have to read-modify-write. */ + u8 reg_io_dir; + u8 reg_output; +}; + +static int fxl6408_gpio_direction_input(struct gpio_chip *gc, unsigned off) +{ + struct fxl6408_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->i2c_lock); + chip->reg_io_dir &= ~BIT(off); + i2c_smbus_write_byte_data(chip->client, FXL6408_IO_DIR, + chip->reg_io_dir); + mutex_unlock(&chip->i2c_lock); + + return 0; +} + +static int fxl6408_gpio_direction_output(struct gpio_chip *gc, + unsigned off, int val) +{ + struct fxl6408_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->i2c_lock); + chip->reg_io_dir |= BIT(off); + i2c_smbus_write_byte_data(chip->client, FXL6408_IO_DIR, + chip->reg_io_dir); + mutex_unlock(&chip->i2c_lock); + + return 0; +} + +static int fxl6408_gpio_get_direction(struct gpio_chip *gc, unsigned off) +{ + struct fxl6408_chip *chip = gpiochip_get_data(gc); + + return (chip->reg_io_dir & BIT(off)) == 0; +} + +static int fxl6408_gpio_get_value(struct gpio_chip *gc, unsigned off) +{ + struct fxl6408_chip *chip = gpiochip_get_data(gc); + u8 reg; + + mutex_lock(&chip->i2c_lock); + reg = i2c_smbus_read_byte_data(chip->client, FXL6408_INPUT_STATUS); + mutex_unlock(&chip->i2c_lock); + + return (reg & BIT(off)) != 0; +} + +static void fxl6408_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) +{ + struct fxl6408_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->i2c_lock); + + if (val) + chip->reg_output |= BIT(off); + else + chip->reg_output &= BIT(off); + + i2c_smbus_write_byte_data(chip->client, FXL6408_OUTPUT, + chip->reg_output); + mutex_unlock(&chip->i2c_lock); +} + + +static void fxl6408_gpio_set_multiple(struct gpio_chip *gc, + unsigned long *mask, unsigned long *bits) +{ + struct fxl6408_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->i2c_lock); + chip->reg_output = (chip->reg_output & ~mask[0]) | bits[0]; + i2c_smbus_write_byte_data(chip->client, FXL6408_OUTPUT, + chip->reg_output); + mutex_unlock(&chip->i2c_lock); +} + +static int fxl6408_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct fxl6408_chip *chip; + struct gpio_chip *gc; + int ret; + u8 device_id; + + /* Check the device ID register to see if it's responding. + * This also clears RST_INT as a side effect, so we won't get + * the "we've been power cycled" interrupt once we enable + * interrupts. + */ + device_id = i2c_smbus_read_byte_data(client, FXL6408_DEVICE_ID); + if (device_id < 0) { + dev_err(dev, "FXL6408 probe returned %d\n", device_id); + return device_id; + } else if (device_id >> 5 != 5) { + dev_err(dev, "FXL6408 probe returned DID: 0x%02x\n", device_id); + return -ENODEV; + } + + /* Disable High-Z of outputs, so that our OUTPUT updates + * actually take effect. + */ + i2c_smbus_write_byte_data(client, FXL6408_OUTPUT_HIGH_Z, 0); + + chip = devm_kzalloc(dev, sizeof(struct fxl6408_chip), GFP_KERNEL); + if (chip == NULL) + return -ENOMEM; + + chip->client = client; + mutex_init(&chip->i2c_lock); + chip->reg_io_dir = i2c_smbus_read_byte_data(client, FXL6408_IO_DIR); + chip->reg_output = i2c_smbus_read_byte_data(client, FXL6408_OUTPUT); + + gc = &chip->gpio_chip; + gc->direction_input = fxl6408_gpio_direction_input; + gc->direction_output = fxl6408_gpio_direction_output; + gc->get_direction = fxl6408_gpio_get_direction; + gc->get = fxl6408_gpio_get_value; + gc->set = fxl6408_gpio_set_value; + gc->set_multiple = fxl6408_gpio_set_multiple; + gc->can_sleep = true; + + gc->base =-1; + gc->ngpio = 8; + gc->label = chip->client->name; + gc->parent = dev; + gc->owner = THIS_MODULE; + + ret = gpiochip_add_data(gc, chip); + if (ret) + return ret; + + i2c_set_clientdata(client, chip); + return 0; +} + +static int fxl6408_remove(struct i2c_client *client) +{ + struct fxl6408_chip *chip = i2c_get_clientdata(client); + + gpiochip_remove(&chip->gpio_chip); + + return 0; +} + +static const struct of_device_id fxl6408_dt_ids[] = { + { .compatible = "fcs,fxl6408" }, + { } +}; + +MODULE_DEVICE_TABLE(of, fxl6408_dt_ids); + +static const struct i2c_device_id fxl6408_id[] = { + { "fxl6408", 0 }, + { }, +}; +MODULE_DEVICE_TABLE(i2c, fxl6408_id); + +static struct i2c_driver fxl6408_driver = { + .driver = { + .name = "fxl6408", + .of_match_table = fxl6408_dt_ids, + }, + .probe = fxl6408_probe, + .remove = fxl6408_remove, + .id_table = fxl6408_id, +}; + +module_i2c_driver(fxl6408_driver); + +MODULE_AUTHOR("Eric Anholt <[email protected]>"); +MODULE_DESCRIPTION("GPIO expander driver for FXL6408"); +MODULE_LICENSE("GPL"); -- 1.8.3.1
