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SubjectRe: [PATCH v5 2/2] gpio: add a reusable generic gpio_chip using regmap
Am 2020-05-28 05:58, schrieb Michael Walle:
> There are quite a lot simple GPIO controller which are using regmap to
> access the hardware. This driver tries to be a base to unify existing
> code into one place. This won't cover everything but it should be a
> good
> starting point.
>
> It does not implement its own irq_chip because there is already a
> generic one for regmap based devices. Instead, the irq_chip will be
> instantiated in the parent driver and its irq domain will be associate
> to this driver.
>
> For now it consists of the usual registers, like set (and an optional
> clear) data register, an input register and direction registers.
> Out-of-the-box, it supports consecutive register mappings and mappings
> where the registers have gaps between them with a linear mapping
> between
> GPIO offset and bit position. For weirder mappings the user can
> register
> its own .xlate().
>
> Signed-off-by: Michael Walle <michael@walle.cc>
> ---
> drivers/gpio/Kconfig | 4 +
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-regmap.c | 352 ++++++++++++++++++++++++++++++++++++
> include/linux/gpio-regmap.h | 70 +++++++
> 4 files changed, 427 insertions(+)
> create mode 100644 drivers/gpio/gpio-regmap.c
> create mode 100644 include/linux/gpio-regmap.h
>
[..]

> --- /dev/null
> +++ b/include/linux/gpio-regmap.h
> @@ -0,0 +1,70 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef _LINUX_GPIO_REGMAP_H
> +#define _LINUX_GPIO_REGMAP_H
> +
> +struct gpio_regmap;
> +
> +#define GPIO_REGMAP_ADDR_ZERO ((unsigned long)(-1))
> +#define GPIO_REGMAP_ADDR(addr) ((addr) ? : GPIO_REGMAP_ADDR_ZERO)
> +
> +/**
> + * struct gpio_regmap_config - Description of a generic regmap
> gpio_chip.
> + *
> + * @parent: The parent device
> + * @regmap: The regmap used to access the registers
> + * given, the name of the device is used
> + * @label: (Optional) Descriptive name for GPIO controller.
> + * If not given, the name of the device is used.
> + * @ngpio: Number of GPIOs
> + * @names: (Optional) Array of names for gpios
> + * @reg_dat_base: (Optional) (in) register base address
> + * @reg_set_base: (Optional) set register base address
> + * @reg_clr_base: (Optional) clear register base address
> + * @reg_dir_in_base: (Optional) in setting register base address
> + * @reg_dir_out_base: (Optional) out setting register base address
> + * @reg_stride: (Optional) May be set if the registers (of the
> + * same type, dat, set, etc) are not consecutive.
> + * @ngpio_per_reg: Number of GPIOs per register
> + * @irq_domain: (Optional) IRQ domain if the controller is
> + * interrupt-capable
> + * @reg_mask_xlate: (Optional) Translates base address and GPIO
> + * offset to a register/bitmask pair. If not
> + * given the default gpio_regmap_simple_xlate()
> + * is used.
> + *
> + * The reg_mask_xlate translates a given base address and GPIO offset
> to
> + * register and mask pair. The base address is one of the given
> reg_*_base.
> + *
> + * All base addresses may have the special value GPIO_REGMAP_ADDR_ZERO
> + * which forces the address to the value 0.
> + */
> +struct gpio_regmap_config {
> + struct device *parent;
> + struct regmap *regmap;
> +
> + const char *label;
> + int ngpio;

damn.. I shouldn't send patches early in the morning. I've forgot to
actually
enable my GPIO driver before compiling. And of course.. it doesn't
compile.

const char *const *names;

is missing here. So I have to send a v6 anyway. Let's wait what Linus
and Bert
says about the location of the gpio-regmap.h header.

Sorry for the noise.

-michael

> +
> + unsigned int reg_dat_base;
> + unsigned int reg_set_base;
> + unsigned int reg_clr_base;
> + unsigned int reg_dir_in_base;
> + unsigned int reg_dir_out_base;
> + int reg_stride;
> + int ngpio_per_reg;
> + struct irq_domain *irq_domain;
> +
> + int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,
> + unsigned int offset, unsigned int *reg,
> + unsigned int *mask);
> +};
> +
> +struct gpio_regmap *gpio_regmap_register(const struct
> gpio_regmap_config *config);
> +void gpio_regmap_unregister(struct gpio_regmap *gpio);
> +struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
> + const struct gpio_regmap_config *config);
> +void gpio_regmap_set_drvdata(struct gpio_regmap *gpio, void *data);
> +void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio);
> +
> +#endif /* _LINUX_GPIO_REGMAP_H */

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