diff options
| -rw-r--r-- | include/sbi_utils/gpio/fdt_gpio.h | 34 | ||||
| -rw-r--r-- | lib/utils/gpio/fdt_gpio.c | 132 | ||||
| -rw-r--r-- | lib/utils/gpio/objects.mk | 1 |
3 files changed, 167 insertions, 0 deletions
diff --git a/include/sbi_utils/gpio/fdt_gpio.h b/include/sbi_utils/gpio/fdt_gpio.h new file mode 100644 index 0000000..19e1b58 --- /dev/null +++ b/include/sbi_utils/gpio/fdt_gpio.h @@ -0,0 +1,34 @@ +/* + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2021 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel <anup.patel@wdc.com> + */ + +#ifndef __FDT_GPIO_H__ +#define __FDT_GPIO_H__ + +#include <sbi_utils/gpio/gpio.h> + +/** FDT based GPIO driver */ +struct fdt_gpio { + const struct fdt_match *match_table; + int (*xlate)(struct gpio_chip *chip, + const struct fdt_phandle_args *pargs, + struct gpio_pin *out_pin); + int (*init)(void *fdt, int nodeoff, u32 phandle, + const struct fdt_match *match); +}; + +/** Get a GPIO pin using "gpios" DT property of client DT node */ +int fdt_gpio_pin_get(void *fdt, int nodeoff, int index, + struct gpio_pin *out_pin); + +/** Simple xlate function to convert two GPIO FDT cells into GPIO pin */ +int fdt_gpio_simple_xlate(struct gpio_chip *chip, + const struct fdt_phandle_args *pargs, + struct gpio_pin *out_pin); + +#endif diff --git a/lib/utils/gpio/fdt_gpio.c b/lib/utils/gpio/fdt_gpio.c new file mode 100644 index 0000000..bff391f --- /dev/null +++ b/lib/utils/gpio/fdt_gpio.c @@ -0,0 +1,132 @@ +/* + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2021 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel <anup.patel@wdc.com> + */ + +#include <libfdt.h> +#include <sbi/sbi_error.h> +#include <sbi_utils/fdt/fdt_helper.h> +#include <sbi_utils/gpio/fdt_gpio.h> + +static struct fdt_gpio *gpio_drivers[] = { +}; + +static struct fdt_gpio *fdt_gpio_driver(struct gpio_chip *chip) +{ + int pos; + + if (!chip) + return NULL; + + for (pos = 0; pos < array_size(gpio_drivers); pos++) { + if (chip->driver == gpio_drivers[pos]) + return gpio_drivers[pos]; + } + + return NULL; +} + +static int fdt_gpio_init(void *fdt, u32 phandle) +{ + int pos, nodeoff, rc; + struct fdt_gpio *drv; + const struct fdt_match *match; + + /* Find node offset */ + nodeoff = fdt_node_offset_by_phandle(fdt, phandle); + if (nodeoff < 0) + return nodeoff; + + /* Check "gpio-controller" property */ + if (!fdt_getprop(fdt, nodeoff, "gpio-controller", &rc)) + return SBI_EINVAL; + + /* Try all GPIO drivers one-by-one */ + for (pos = 0; pos < array_size(gpio_drivers); pos++) { + drv = gpio_drivers[pos]; + + match = fdt_match_node(fdt, nodeoff, drv->match_table); + if (match && drv->init) { + rc = drv->init(fdt, nodeoff, phandle, match); + if (rc == SBI_ENODEV) + continue; + if (rc) + return rc; + return 0; + } + } + + return SBI_ENOSYS; +} + +static int fdt_gpio_chip_find(void *fdt, u32 phandle, + struct gpio_chip **out_chip) +{ + int rc; + struct gpio_chip *chip = gpio_chip_find(phandle); + + if (!chip) { + /* GPIO chip not found so initialize matching driver */ + rc = fdt_gpio_init(fdt, phandle); + if (rc) + return rc; + + /* Try to find GPIO chip again */ + chip = gpio_chip_find(phandle); + if (!chip) + return SBI_ENOSYS; + } + + if (out_chip) + *out_chip = chip; + + return 0; +} + +int fdt_gpio_pin_get(void *fdt, int nodeoff, int index, + struct gpio_pin *out_pin) +{ + int rc; + u32 phandle; + struct fdt_gpio *drv; + struct gpio_chip *chip = NULL; + struct fdt_phandle_args pargs; + + if (!fdt || (nodeoff < 0) || (index < 0) || !out_pin) + return SBI_EINVAL; + + pargs.node_offset = pargs.args_count = 0; + rc = fdt_parse_phandle_with_args(fdt, nodeoff, + "gpios", "#gpio-cells", + index, &pargs); + if (rc) + return rc; + + phandle = fdt_get_phandle(fdt, pargs.node_offset); + rc = fdt_gpio_chip_find(fdt, phandle, &chip); + if (rc) + return rc; + + drv = fdt_gpio_driver(chip); + if (!drv || !drv->xlate) + return SBI_ENOSYS; + + return drv->xlate(chip, &pargs, out_pin); +} + +int fdt_gpio_simple_xlate(struct gpio_chip *chip, + const struct fdt_phandle_args *pargs, + struct gpio_pin *out_pin) +{ + if ((pargs->args_count < 2) || (chip->ngpio <= pargs->args[0])) + return SBI_EINVAL; + + out_pin->chip = chip; + out_pin->offset = pargs->args[0]; + out_pin->flags = pargs->args[1]; + return 0; +} diff --git a/lib/utils/gpio/objects.mk b/lib/utils/gpio/objects.mk index e99a895..dade45e 100644 --- a/lib/utils/gpio/objects.mk +++ b/lib/utils/gpio/objects.mk @@ -7,4 +7,5 @@ # Anup Patel <anup.patel@wdc.com> # +libsbiutils-objs-y += gpio/fdt_gpio.o libsbiutils-objs-y += gpio/gpio.o |