Hi Oleksandr, On Wed, 21 Jul 2021 at 06:21, Oleksandr Suvorov <oleksandr.suvo...@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.suvo...@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 <s...@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 <e...@anholt.net>: > + * https://patchwork.kernel.org/patch/9148419/ > + * - the Toradex version by Max Krummenacher <max.krummenac...@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.free...@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
