[PATCH 1/2] GPIO: fxl6408: Add support for FXL6408 GPIO expander
Simon Glass
sjg at chromium.org
Sun Jul 25 00:01:15 CEST 2021
Hi Oleksandr,
On Wed, 21 Jul 2021 at 06:21, Oleksandr Suvorov
<oleksandr.suvorov at toradex.com> wrote:
>
> Initial support for Fairchild's 8 bit I2C gpio expander FXL6408.
> The CONFIG_FXL6408_GPIO define enables support for such devices.
>
> Based on: https://patchwork.kernel.org/patch/9148419/
>
> Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov at toradex.com>
> ---
>
> drivers/gpio/Kconfig | 7 +
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-fxl6408.c | 371 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 379 insertions(+)
> create mode 100644 drivers/gpio/gpio-fxl6408.c
Reviewed-by: Simon Glass <sjg at chromium.org>
Lots of nits below
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 0817b12c5f..5883582a7f 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -123,6 +123,13 @@ config DA8XX_GPIO
> help
> This driver supports the DA8xx GPIO controller
>
> +config FXL6408_GPIO
> + bool "FXL6408 I2C GPIO driver"
> + depends on DM_GPIO && DM_I2C
> + help
> + Support for Fairchild Semiconductor FXL6408 I2C 8-bit GPIO
> + expander.
Please add some more details here.
[..]
> diff --git a/drivers/gpio/gpio-fxl6408.c b/drivers/gpio/gpio-fxl6408.c
> new file mode 100644
> index 0000000000..282ec0a69c
> --- /dev/null
> +++ b/drivers/gpio/gpio-fxl6408.c
> @@ -0,0 +1,371 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Toradex
> + * Copyright (C) 2016 Broadcom
> + */
> +
> +/**
> + * DOC: FXL6408 I2C to GPIO expander.
> + *
> + * This chip 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 state changes.
> + *
> + * Any preconfigured state will be left in place until the GPIO lines
> + * get activated. At power on, everything is treated as an input,
> + * default input is HIGH and pulled-up, all interrupts are masked.
> + *
> + * Documentation can be found at:
> + * https://www.fairchildsemi.com/datasheets/FX/FXL6408.pdf
> + *
> + * This driver bases on:
> + * - the original driver by Eric Anholt <eric at anholt.net>:
> + * https://patchwork.kernel.org/patch/9148419/
> + * - the Toradex version by Max Krummenacher <max.krummenacher at toradex.com>:
> + * http://git.toradex.com/cgit/linux-toradex.git/tree/drivers/gpio/gpio-fxl6408.c?h=toradex_5.4-2.3.x-imx
> + * - the U-boot PCA953x driver by Peng Fan <van.freenix at gmail.com>:
> + * drivers/gpio/pca953x_gpio.c
> + *
> + * TODO: Add interrupts support
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <dm/device_compat.h>
> +#include <i2c.h>
> +#include <log.h>
> +#include <asm-generic/gpio.h>
> +#include <asm/global_data.h>
> +#include <linux/bitops.h>
> +#include <dt-bindings/gpio/gpio.h>
> +
> +#define FXL6408_DEVID_CTRL 0x01
Do you need the FXL6408 prefix?
> +# define FXL6408_SW_RST BIT(0)
> +# define FXL6408_RST_INT BIT(1)
> +
> +/* 3-bit manufacturer ID */
> +# define FXL6408_MF_MASK GENMASK(7, 5)
> +# define FXL6408_MF_ID(devid) (((devid) & FXL6408_MF_MASK) >> 5)
> +/* 0b101 is for Fairchild assigned by Nokia */
> +# define FXL6408_FAIRCHILD_MF 5
> +
> +/* 3-bit firmware revision */
> +# define FXL6408_FW_MASK GENMASK(4, 2)
> +# define FXL6408_FW_REV(devid) (((devid) & FXL6408_FW_MASK) >> 2)
This is only used once, so why not include that code inline below?
> +
> +/*
> + * Bits set here indicate that the GPIO is an output.
single-line comment style is /* ... */
> + */
> +#define FXL6408_DIRECTION 0x03
Then call it DIR_MASK ?
> +
> +enum {
> + FXL6408_DIRECTION_IN,
> + FXL6408_DIRECTION_OUT,
> +};
> +
> +/*
> + * 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_STATUS bits will be set when the INPUT transitions away
> + * from this value.
> + */
> +#define FXL6408_INPUT_DEF_STATE 0x09
> +
> +/*
> + * Bits here enable either pull up or pull down according to
> + * INPUT_PULL_STATE.
> + */
> +#define FXL6408_INPUT_PULL_ENABLE 0x0b
> +
> +/*
> + * Bits set here selects a pull-up/pull-down state of pin, which
> + * is configured as Input and the corresponding PULL_ENABLE bit is
> + * set.
> + */
> +#define FXL6408_INPUT_PULL_STATE 0x0d
> +
> +/*
> + * Returns the current status (1 = HIGH) of the input pins.
> + */
> +#define FXL6408_INPUT 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_STATUS 0x13
> +
> +/*
> + * struct fxl6408_info - Data for fxl6408
> + *
> + * @dev: udevice structure for the device
> + * @addr: i2c slave address
Please check; these don't match the struct.
> + * @reg_output: hold the value of output register
> + * @reg_direction: hold the value of direction register
> + */
> +struct fxl6408_info {
> + struct udevice *dev;
> + int addr;
> + u8 device_id;
> + u8 reg_io_dir;
> + u8 reg_output;
> +};
> +
> +static int fxl6408_write(struct udevice *dev, int reg, u8 val)
> +{
> + int ret;
> +
> + ret = dm_i2c_write(dev, reg, &val, 1);
> + if (ret)
> + dev_err(dev, "%s error: %d\n", __func__, ret);
> +
> + return ret;
> +}
> +
> +static int fxl6408_read(struct udevice *dev, int reg, u8 *val)
You could return the value, or -ve for error, saving a parameter.
> +{
> + int ret;
> + u8 tmp;
> +
> + ret = dm_i2c_read(dev, reg, &tmp, 1);
> + if (!ret)
> + *val = tmp;
> + else
> + dev_err(dev, "%s error: %d\n", __func__, ret);
> +
> + return ret;
> +}
> +
> +/*
> + * fxl6408_is_output() - check whether the gpio configures as either
> + * output or input.
> + * Return: 0 - input, 1 - output.
> + */
> +static int fxl6408_is_output(struct udevice *dev, int offset)
s/int/bool/ and you can drop the !! here and below
> +{
> + struct fxl6408_info *info = dev_get_plat(dev);
> +
> + return !!(info->reg_io_dir & BIT(offset));
> +}
> +
> +static int fxl6408_get_value(struct udevice *dev, uint offset)
> +{
> + int ret, reg = fxl6408_is_output(dev, offset) ? FXL6408_OUTPUT : FXL6408_INPUT;
> + u8 val = 0;
> +
> + ret = fxl6408_read(dev, reg, &val);
> + if (IS_ERR_VALUE(ret))
> + return ret;
> +
> + return !!(val & BIT(offset));
> +}
> +
> +static int fxl6408_set_value(struct udevice *dev, uint offset, int value)
> +{
> + struct fxl6408_info *info = dev_get_plat(dev);
> + u8 val;
> + int ret;
> +
> + if (value)
> + val = info->reg_output | BIT(offset);
> + else
> + val = info->reg_output & ~BIT(offset);
> +
> + ret = fxl6408_write(dev, FXL6408_OUTPUT, val);
> + if (!IS_ERR_VALUE(ret))
if (ret < 0) is good enough here
We are not going to change that, and the macros obfuscates things IMO.
> + info->reg_output = val;
> +
> + return ret;
> +}
> +
> +static int fxl6408_set_direction(struct udevice *dev, uint offset, int dir)
> +{
> + struct fxl6408_info *info = dev_get_plat(dev);
> + u8 val;
> + int ret;
> +
> + if (dir == FXL6408_DIRECTION_IN)
Then shouldn't 'dir' be an enum?
> + val = info->reg_io_dir & ~BIT(offset);
> + else
> + val = info->reg_io_dir | BIT(offset);
> +
> + ret = fxl6408_write(dev, FXL6408_DIRECTION, val);
> + if (!IS_ERR_VALUE(ret))
> + info->reg_io_dir = val;
> +
> + return ret;
> +}
> +
> +static int fxl6408_direction_input(struct udevice *dev, uint offset)
> +{
> + return fxl6408_set_direction(dev, offset, FXL6408_DIRECTION_IN);
> +}
> +
> +static int fxl6408_direction_output(struct udevice *dev, uint offset, int value)
> +{
> + int ret;
> +
> + /* Configure output value. */
> + ret = fxl6408_set_value(dev, offset, value);
> + if (!IS_ERR_VALUE(ret))
> + /* Configure direction as output. */
> + fxl6408_set_direction(dev, offset, FXL6408_DIRECTION_OUT);
> +
> + return ret;
> +}
> +
> +static int fxl6408_get_function(struct udevice *dev, uint offset)
> +{
> + if (fxl6408_is_output(dev, offset))
> + return GPIOF_OUTPUT;
> + else
> + return GPIOF_INPUT;
> +}
> +
> +static int fxl6408_xlate(struct udevice *dev, struct gpio_desc *desc,
> + struct ofnode_phandle_args *args)
> +{
> + desc->offset = args->args[0];
> + desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
> +
> + return 0;
> +}
> +
> +static const struct dm_gpio_ops fxl6408_ops = {
> + .direction_input = fxl6408_direction_input,
> + .direction_output = fxl6408_direction_output,
> + .get_value = fxl6408_get_value,
> + .set_value = fxl6408_set_value,
> + .get_function = fxl6408_get_function,
> + .xlate = fxl6408_xlate,
> +};
Can you put that down below with the other struct?
> +
> +static int fxl6408_probe(struct udevice *dev)
> +{
> + struct fxl6408_info *info = dev_get_plat(dev);
> + struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
> + char name[32], label[32], *str;
> + int addr;
> + int ret;
> + int size;
> + const u8 *tmp;
> + u8 val;
> + u32 val32;
> +
> + addr = dev_read_addr(dev);
> + if (addr == 0)
> + return -ENODEV;
This has a special meaning in drive model. Try -EINVAL instead for
errors reading the DT.
> + info->addr = addr;
> +
> + /* Check the device ID register to see if it's responding.
Multi-line comment style is:
/*
* Check the
* ..
*/
> + * 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.
> + */
> + ret = fxl6408_read(dev, FXL6408_DEVID_CTRL, &val);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "FXL6408 probe returned %d\n", ret);
> + return ret;
> + }
> +
> + if (FXL6408_MF_ID(val) != FXL6408_FAIRCHILD_MF) {
> + dev_err(dev, "FXL6408 probe returned DID: 0x%02x\n", val);
> + return -ENODEV;
Again you cannot return this, as there is a device. How about -ENXIO?
> + }
> + info->device_id = val;
> +
> + /*
> + * Disable High-Z of outputs, so that the OUTPUT updates
> + * actually take effect.
> + */
> + ret = fxl6408_write(dev, FXL6408_OUTPUT_HIGH_Z, (u8)0);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "Error writing High-Z register\n");
> + return ret;
> + }
> +
> + /*
> + * If configured, set initial output state and direction,
> + * otherwise read them from the chip.
> + */
> + if (IS_ERR_VALUE(dev_read_u32(dev, "initial_io_dir", &val32))) {
> + ret = fxl6408_read(dev, FXL6408_DIRECTION, &info->reg_io_dir);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "Error reading direction register\n");
> + return ret;
> + }
> + } else {
> + info->reg_io_dir = val32 & 0xFF;
> + ret = fxl6408_write(dev, FXL6408_DIRECTION, info->reg_io_dir);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "Error setting direction register\n");
> + return ret;
> + }
> + }
> +
> + if (IS_ERR_VALUE(dev_read_u32(dev, "initial_output", &val32))) {
> + ret = fxl6408_read(dev, FXL6408_OUTPUT, &info->reg_output);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "Error reading output register\n");
> + return ret;
> + }
> + } else {
> + info->reg_output = val32 & 0xFF;
> + ret = fxl6408_write(dev, FXL6408_OUTPUT, info->reg_output);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "Error setting output register\n");
> + return ret;
> + }
> + }
> +
> + tmp = dev_read_prop(dev, "label", &size);
> + if (tmp) {
> + size = min(size, (int)sizeof(label) - 1);
> + memcpy(label, tmp, size);
> + label[size] = '\0';
> + snprintf(name, sizeof(name), "%s@%x_", label, info->addr);
> + } else {
> + snprintf(name, sizeof(name), "gpio@%x_", info->addr);
> + }
> +
> + str = strdup(name);
> + if (!str)
> + return -ENOMEM;
> +
> + uc_priv->bank_name = str;
> + uc_priv->gpio_count = dev_get_driver_data(dev);
> + uc_priv->gpio_base = -1;
> +
> + dev_dbg(dev, "%s (FW rev. %ld) is ready\n", str,
> + FXL6408_FW_REV(info->device_id));
> +
> + return 0;
> +}
> +
> +static const struct udevice_id fxl6408_ids[] = {
> + { .compatible = "fcs,fxl6408", .data = 8 },
> + { }
> +};
> +
> +U_BOOT_DRIVER(fxl6408_gpio) = {
> + .name = "fxl6408_gpio",
> + .id = UCLASS_GPIO,
> + .ops = &fxl6408_ops,
> + .probe = fxl6408_probe,
> + .of_match = fxl6408_ids,
> + .plat_auto = sizeof(struct fxl6408_info),
> +};
> --
> 2.31.1
>
Regards,
Simon
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