This uses the newly-added dm_gpio_get_values_as_int_base3 function to implement a sysinfo device. The revision map is stored in the device tree.
Signed-off-by: Sean Anderson sean.anderson@seco.com ---
.../sysinfo/gpio-sysinfo.txt | 37 +++++ drivers/sysinfo/Kconfig | 8 + drivers/sysinfo/Makefile | 1 + drivers/sysinfo/gpio.c | 138 ++++++++++++++++++ 4 files changed, 184 insertions(+) create mode 100644 doc/device-tree-bindings/sysinfo/gpio-sysinfo.txt create mode 100644 drivers/sysinfo/gpio.c
diff --git a/doc/device-tree-bindings/sysinfo/gpio-sysinfo.txt b/doc/device-tree-bindings/sysinfo/gpio-sysinfo.txt new file mode 100644 index 0000000000..b5739d94e9 --- /dev/null +++ b/doc/device-tree-bindings/sysinfo/gpio-sysinfo.txt @@ -0,0 +1,37 @@ +GPIO-based Sysinfo device + +This binding describes several GPIOs which specify a board revision. Each GPIO +forms a digit in a ternary revision number. This revision is then mapped to a +name using the revisions and names properties. + +Each GPIO may be floating, pulled-up, or pulled-down, mapping to digits 2, 1, +and 0, respectively. The first GPIO forms the least-significant digit of the +revision. For example, consider the property + + gpios = <&gpio 0>, <&gpio 1>, <&gpio 2>; + +If GPIO 0 is pulled-up, GPIO 1 is pulled-down, and GPIO 2 is floating, then the +revision would be + + 0t201 = 2*9 + 0*3 + 1*3 = 19 + +If instead GPIO 0 is floating, GPIO 1 is pulled-up, and GPIO 2 is pulled-down, +then the revision would be + + 0t012 = 0*9 + 1*3 + 2*1 = 5 + +Required properties: +- compatible: should be "gpio-sysinfo". +- gpios: should be a list of gpios forming the revision number, + least-significant-digit first +- revisions: a list of known revisions; any revisions not present will have the + name "unknown" +- names: the name of each revision in revisions + +Example: +sysinfo { + compatible = "gpio-sysinfo"; + gpios = <&gpio_a 15>, <&gpio_a 16>, <&gpio_a 17>; + revisions = <19>, <5>; + names = "rev_a", "foo"; +}; diff --git a/drivers/sysinfo/Kconfig b/drivers/sysinfo/Kconfig index 85c1e81e41..381dcd8844 100644 --- a/drivers/sysinfo/Kconfig +++ b/drivers/sysinfo/Kconfig @@ -30,4 +30,12 @@ config SYSINFO_SMBIOS one which provides a way to specify this SMBIOS information in the devicetree, without needing any board-specific functionality.
+config SYSINFO_GPIO + bool "Enable gpio sysinfo driver" + help + Support querying gpios to determine board revision. This uses gpios to + form a ternary number (when they are pulled-up, -down, or floating). + This ternary number is then mapped to a board revision name using + device tree properties. + endif diff --git a/drivers/sysinfo/Makefile b/drivers/sysinfo/Makefile index 6d04fcba1d..d9f708b7ea 100644 --- a/drivers/sysinfo/Makefile +++ b/drivers/sysinfo/Makefile @@ -4,5 +4,6 @@ # Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc obj-y += sysinfo-uclass.o obj-$(CONFIG_SYSINFO_GAZERBEAM) += gazerbeam.o +obj-$(CONFIG_SYSINFO_GPIO) += gpio.o obj-$(CONFIG_SYSINFO_SANDBOX) += sandbox.o obj-$(CONFIG_SYSINFO_SMBIOS) += smbios.o diff --git a/drivers/sysinfo/gpio.c b/drivers/sysinfo/gpio.c new file mode 100644 index 0000000000..6a0eff3ec9 --- /dev/null +++ b/drivers/sysinfo/gpio.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2021 Sean Anderson sean.anderson@seco.com + */ + +#include <common.h> +#include <dm.h> +#include <dm/device_compat.h> +#include <log.h> +#include <sysinfo.h> +#include <asm/gpio.h> + +struct sysinfo_gpio_priv { + struct gpio_desc *gpios; + int gpio_num, revision; +}; + +static int sysinfo_gpio_detect(struct udevice *dev) +{ + struct sysinfo_gpio_priv *priv = dev_get_priv(dev); + + priv->revision = dm_gpio_get_values_as_int_base3(priv->gpios, + priv->gpio_num); + return priv->revision < 0 ? priv->revision : 0; +} + +static int sysinfo_gpio_get_int(struct udevice *dev, int id, int *val) +{ + struct sysinfo_gpio_priv *priv = dev_get_priv(dev); + + switch (id) { + case SYSINFO_ID_REVISION: + if (priv->revision < 0) { + return priv->revision; + *val = priv->revision; + return 0; + default: + return -EINVAL; + }; +} + +static int sysinfo_gpio_get_str(struct udevice *dev, int id, size_t size, char *val) +{ + struct sysinfo_gpio_priv *priv = dev_get_priv(dev); + + switch (id) { + case SYSINFO_ID_REVISION: { + const char *name = NULL; + int i, ret; + u32 revision; + + if (priv->revision < 0) + return priv->revision; + + for (i = 0; i < priv->gpio_num; i++) { + ret = dev_read_u32_index(dev, "revisions", i, + &revision); + if (ret) { + if (ret != -EOVERFLOW) + return ret; + break; + } + + if (revision == priv->revision) { + ret = dev_read_string_index(dev, "names", i, + &name); + if (ret < 0) + return ret; + break; + } + } + if (!name) + name = "unknown"; + + strncpy(val, name, size); + val[size - 1] = '\0'; + return 0; + } default: + return -EINVAL; + }; +} + +static const struct sysinfo_ops sysinfo_gpio_ops = { + .detect = sysinfo_gpio_detect, + .get_int = sysinfo_gpio_get_int, + .get_str = sysinfo_gpio_get_str, +}; + +static int sysinfo_gpio_probe(struct udevice *dev) +{ + int ret; + struct sysinfo_gpio_priv *priv = dev_get_priv(dev); + + priv->gpio_num = gpio_get_list_count(dev, "gpios"); + if (priv->gpio_num < 0) { + dev_err(dev, "could not get gpios length (err = %d)\n", + priv->gpio_num); + return priv->gpio_num; + } + + priv->gpios = calloc(priv->gpio_num, sizeof(*priv->gpios)); + if (!priv->gpios) { + dev_err(dev, "could not allocate memory for %d gpios\n", + priv->gpio_num); + return -ENOMEM; + } + + ret = gpio_request_list_by_name(dev, "gpios", priv->gpios, + priv->gpio_num, GPIOD_IS_IN); + if (ret != priv->gpio_num) { + dev_err(dev, "could not get gpios (err = %d)\n", + priv->gpio_num); + return ret; + } + + if (!dev_read_bool(dev, "revisions") || !dev_read_bool(dev, "names")) { + dev_err(dev, "revisions or names properties missing\n"); + return -ENOENT; + } + + priv->revision = -ENOENT; + + return 0; +} + +static const struct udevice_id sysinfo_gpio_ids[] = { + { .compatible = "gpio-sysinfo" }, + { /* sentinel */ } +}; + +U_BOOT_DRIVER(sysinfo_gpio) = { + .name = "sysinfo_gpio", + .id = UCLASS_SYSINFO, + .of_match = sysinfo_gpio_ids, + .ops = &sysinfo_gpio_ops, + .priv_auto = sizeof(struct sysinfo_gpio_priv), + .probe = sysinfo_gpio_probe, +};