Re: [PATCH 4/5] sysinfo: Add gpio-sysinfo driver

On 3/1/21 3:46 PM, Sean Anderson wrote:

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) {
  

Looks like I forgot to remove this brace. Will be fixed in v2.

--Sean

• 	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,

+};