[RFC PATCH 3/4] lib: utils: add gpio generic interface
Bin Meng
bmeng.cn at gmail.com
Thu Jul 1 07:00:01 PDT 2021
On Thu, Jul 1, 2021 at 5:02 PM Green Wan <green.wan at sifive.com> wrote:
>
> Add generic interface for GPIO driver and add SiFive GPIO
> driver as an example. Currently, driver supports gpio output
> function only.
>
> lib/utils/gpio/fdt_gpio.c:
> - contains GPIO generic interfaces.
>
> lib/utils/gpio/sifive_gpio.c:
> - contains sifive GPIO driver.
>
> platform/generic/platform.c:
> - add entry of gpio init
>
> Signed-off-by: Green Wan <green.wan at sifive.com>
> ---
> include/sbi/sbi_gpio.h | 23 ++++++++++
> include/sbi_utils/gpio/fdt_gpio.h | 32 ++++++++++++++
> lib/utils/gpio/fdt_gpio.c | 55 ++++++++++++++++++++++++
> lib/utils/gpio/objects.mk | 11 +++++
> lib/utils/gpio/sifive_gpio.c | 70 +++++++++++++++++++++++++++++++
> platform/generic/platform.c | 3 ++
> 6 files changed, 194 insertions(+)
> create mode 100644 include/sbi/sbi_gpio.h
> create mode 100644 include/sbi_utils/gpio/fdt_gpio.h
> create mode 100644 lib/utils/gpio/fdt_gpio.c
> create mode 100644 lib/utils/gpio/objects.mk
> create mode 100644 lib/utils/gpio/sifive_gpio.c
>
> diff --git a/include/sbi/sbi_gpio.h b/include/sbi/sbi_gpio.h
> new file mode 100644
> index 0000000..67ef9a9
> --- /dev/null
> +++ b/include/sbi/sbi_gpio.h
> @@ -0,0 +1,23 @@
> +/*
> + * SPDX-License-Identifier: GPL 2.0+
> + *
> + * Copyright (c) 2021 SiFive.
> + *
> + * Authors:
> + * Green Wan <green.wan at sifive.com>
> + */
> +
> +#ifndef __SBI_GPIO_H__
> +#define __SBI_GPIO_H__
> +
> +#include <sbi/sbi_types.h>
> +
> +struct sbi_scratch;
> +
> +/* Initialize gpio */
> +int sbi_gpio_init(struct sbi_scratch *scratch, bool cold_boot);
> +
> +/* Exit gpio */
> +void sbi_gpio_exit(struct sbi_scratch *scratch);
> +
> +#endif
> diff --git a/include/sbi_utils/gpio/fdt_gpio.h b/include/sbi_utils/gpio/fdt_gpio.h
> new file mode 100644
> index 0000000..c66380a
> --- /dev/null
> +++ b/include/sbi_utils/gpio/fdt_gpio.h
> @@ -0,0 +1,32 @@
> +/*
> + * SPDX-License-Identifier: GPL 2.0+
> + *
> + * Copyright (c) 2021 SiFive
> + *
> + * Authors:
> + * Green Wan <green.wan at sifive.com>
> + */
> +
> +#ifndef __FDT_GPIO_H__
> +#define __FDT_GPIO_H__
> +
> +#include <sbi/sbi_types.h>
> +
> +/**
> + * Make a GPIO an output, and set its value.
> + *
> + * @param gpio GPIO number
> + * @param value GPIO value (0 for low or 1 for high)
> + * @return 0 if ok, -1 on error
> + */
> +int gpio_direction_output(unsigned int gpio, unsigned int value);
> +
> +struct fdt_gpio {
> + const struct fdt_match *match_table;
> + int (*init)(void *fdt, int nodeoff, const struct fdt_match *match);
> + int (*direction_output)(unsigned int gpio, unsigned int value);
> +};
> +
> +int fdt_gpio_init(void);
> +
> +#endif
> diff --git a/lib/utils/gpio/fdt_gpio.c b/lib/utils/gpio/fdt_gpio.c
> new file mode 100644
> index 0000000..732598b
> --- /dev/null
> +++ b/lib/utils/gpio/fdt_gpio.c
> @@ -0,0 +1,55 @@
> +/*
> + * SPDX-License-Identifier: GPL 2.0+
> + *
> + * Copyright (c) 2021 SiFive
> + *
> + * Authors:
> + * Green Wan <green.wan at sifive.com>
> + */
> +
> +#include <sbi/sbi_scratch.h>
> +#include <sbi/sbi_console.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/gpio/fdt_gpio.h>
> +
> +extern struct fdt_gpio sifive_gpio;
> +
> +static struct fdt_gpio *gpio_drivers[] = {
> + &sifive_gpio
> +};
> +
> +static struct fdt_gpio *current_driver;
> +
> +int gpio_direction_output(unsigned int gpio, unsigned int value)
> +{
> + if (current_driver->direction_output)
> + return current_driver->direction_output(gpio, value);
> +
> + return 0;
> +}
> +
> +int fdt_gpio_init(void)
> +{
> + int pos, noff, rc;
> + struct fdt_gpio *drv;
> + const struct fdt_match *match;
> + void *fdt = sbi_scratch_thishart_arg1_ptr();
> +
> + for (pos = 0; pos < array_size(gpio_drivers); pos++) {
> + drv = gpio_drivers[pos];
> +
> + noff = -1;
> + while ((noff = fdt_find_match(fdt, noff,
> + drv->match_table,
> + &match)) >= 0) {
> + if (drv->init) {
> + rc = drv->init(fdt, noff, match);
> + if (rc)
> + return rc;
> + }
> + current_driver = drv;
> + }
> + }
> +
> + return 0;
> +}
> diff --git a/lib/utils/gpio/objects.mk b/lib/utils/gpio/objects.mk
> new file mode 100644
> index 0000000..727c567
> --- /dev/null
> +++ b/lib/utils/gpio/objects.mk
> @@ -0,0 +1,11 @@
> +#
> +# SPDX-License-Identifier: GPL 2.0+
> +#
> +# Copyright (c) 2020 SiFive Inc.
> +#
> +# Authors:
> +# Green Wan <green.wan at sifive.com>
> +#
> +
> +libsbiutils-objs-y += gpio/fdt_gpio.o
> +libsbiutils-objs-y += gpio/sifive_gpio.o
> diff --git a/lib/utils/gpio/sifive_gpio.c b/lib/utils/gpio/sifive_gpio.c
> new file mode 100644
> index 0000000..714e127
> --- /dev/null
> +++ b/lib/utils/gpio/sifive_gpio.c
> @@ -0,0 +1,70 @@
> +/*
> + * SPDX-License-Identifier: GPL 2.0+
> + *
> + * Copyright (c) 2021 SiFive
> + *
> + * Authors:
> + * Green Wan <green.wan at sifive.com>
> + */
> +
> +#include <sbi/riscv_io.h>
> +#include <sbi/sbi_error.h>
> +#include <sbi/sbi_console.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/gpio/fdt_gpio.h>
> +
> +#define GPIO_OUTEN 0x8
> +#define GPIO_OUTVAL 0xC
> +#define GPIO_BIT(b) (1UL << (b))
> +
> +static struct platform_gpio_data gpio_data = {
> + .addr = 0x0
> +};
> +
> +static int sifive_gpio_init(void *fdt, int nodeoff,
> + const struct fdt_match *match)
> +{
> + int rc;
> +
> + rc = fdt_parse_gpio_node(fdt, nodeoff, &gpio_data);
This won't work if there are more than 1 gpio controller.
> + if (rc)
> + return rc;
> +
> + return 0;
> +}
> +
> +static int sifive_gpio_direction_output(unsigned int gpio,
> + unsigned int out)
> +{
> + if (gpio_data.addr != 0) {
> + unsigned int val;
> +
> + val = readl((volatile void *)(gpio_data.addr + GPIO_OUTEN));
> + val |= GPIO_BIT(gpio);
> + writel(val, (volatile void *)(gpio_data.addr + GPIO_OUTEN));
> +
> + val = readl((volatile void *)(gpio_data.addr + GPIO_OUTVAL));
> +
> + if (!out)
> + val &= ~GPIO_BIT(gpio);
> + else
> + val |= GPIO_BIT(gpio);
> +
> + writel(val, (volatile void *)(gpio_data.addr + GPIO_OUTVAL));
> +
> + return 0;
> + }
> +
> + return SBI_EINVAL;
> +}
> +
> +static const struct fdt_match sifive_gpio_match[] = {
> + { .compatible = "sifive,gpio0" },
> + { },
> +};
> +
> +struct fdt_gpio sifive_gpio = {
> + .match_table = sifive_gpio_match,
> + .init = sifive_gpio_init,
> + .direction_output = sifive_gpio_direction_output,
> +};
> diff --git a/platform/generic/platform.c b/platform/generic/platform.c
> index da0c1af..39017f0 100644
> --- a/platform/generic/platform.c
> +++ b/platform/generic/platform.c
> @@ -16,6 +16,7 @@
> #include <sbi_utils/fdt/fdt_domain.h>
> #include <sbi_utils/fdt/fdt_fixup.h>
> #include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/gpio/fdt_gpio.h>
> #include <sbi_utils/irqchip/fdt_irqchip.h>
> #include <sbi_utils/serial/fdt_serial.h>
> #include <sbi_utils/timer/fdt_timer.h>
> @@ -128,6 +129,8 @@ static int generic_early_init(bool cold_boot)
> if (!cold_boot)
> return 0;
>
> + fdt_gpio_init();
> +
> return fdt_reset_init();
> }
>
Regards,
Bin
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