[RFC] pinctrl: add helper to expose pinctrl state in debugfs

Message ID	20201211042625.129255-1-drew@beagleboard.org
State	New
Headers	show Return-Path: <linux-gpio-owner@vger.kernel.org> From: Drew Fustini <drew@beagleboard.org> To: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Drew Fustini <drew@beagleboard.org>, Pantelis Antoniou <panto@antoniou-consulting.com>, Linus Walleij <linus.walleij@linaro.org>, Tony Lindgren <tony@atomide.com> Subject: [RFC PATCH] pinctrl: add helper to expose pinctrl state in debugfs Date: Thu, 10 Dec 2020 20:26:29 -0800 Message-Id: <20201211042625.129255-1-drew@beagleboard.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	[RFC] pinctrl: add helper to expose pinctrl state in debugfs \| expand [RFC] pinctrl: add helper to expose pinctrl state in debugfs

diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig index 8828613c4e0e..4faed5c8c83b 100644 --- a/drivers/pinctrl/Kconfig +++ b/drivers/pinctrl/Kconfig @@ -255,6 +255,16 @@ config PINCTRL_SINGLE help This selects the device tree based generic pinctrl driver. +config PINCTRL_STATE_HELPER + tristate "Helper to expose pinctrl state to debugfs" + depends on OF + depends on HAS_IOMEM + select GENERIC_PINCTRL_GROUPS + select GENERIC_PINMUX_FUNCTIONS + select GENERIC_PINCONF + help + This selects the device tree based generic pinctrl driver. + config PINCTRL_SIRF bool "CSR SiRFprimaII pin controller driver" depends on ARCH_SIRF diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile index 1731b2154df9..156c356dbd3f 100644 --- a/drivers/pinctrl/Makefile +++ b/drivers/pinctrl/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_PINCTRL_RZA1) += pinctrl-rza1.o obj-$(CONFIG_PINCTRL_RZA2) += pinctrl-rza2.o obj-$(CONFIG_PINCTRL_RZN1) += pinctrl-rzn1.o obj-$(CONFIG_PINCTRL_SINGLE) += pinctrl-single.o +obj-$(CONFIG_PINCTRL_STATE_HELPER) += pinctrl-state-helper.o obj-$(CONFIG_PINCTRL_SIRF) += sirf/ obj-$(CONFIG_PINCTRL_SX150X) += pinctrl-sx150x.o obj-$(CONFIG_ARCH_TEGRA) += tegra/ diff --git a/drivers/pinctrl/pinctrl-state-helper.c b/drivers/pinctrl/pinctrl-state-helper.c new file mode 100644 index 000000000000..d11edb9ee9b4 --- /dev/null +++ b/drivers/pinctrl/pinctrl-state-helper.c @@ -0,0 +1,233 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Pinmux state helper driver + * + * Copyright (C) 2013 Pantelis Antoniou <panto@antoniou-consulting.com> + * Copyright (C) 2020 Drew Fustini <drew@beagleboard.org> + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/list.h> +#include <linux/interrupt.h> + +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_address.h> + +#include <linux/pinctrl/pinctrl.h> +#include <linux/pinctrl/pinmux.h> +#include <linux/pinctrl/pinconf-generic.h> +#include <linux/kernel.h> +#include <linux/errno.h> + +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <linux/seq_file.h> +#include <linux/dcache.h> + +#include "core.h" +#include "devicetree.h" +#include "pinconf.h" +#include "pinmux.h" + +#define DRIVER_NAME "pinctrl_state_helper" + +struct pinctrl_state_helper_priv { + unsigned int offset; + struct device *dev; + struct pinctrl *pinctrl; + char selected_state_name[64]; +}; + +static ssize_t pinctrl_state_read(struct file *file, + char __user *usr_buf, + size_t size, loff_t *ppos) +{ + int cnt; + char buf[64]; + struct pinctrl_state_helper_priv *priv; + struct seq_file *sfile; + char *state_name; + + sfile = file->private_data; + priv = sfile->private; + state_name = priv->selected_state_name; + if (state_name == NULL || strlen(state_name) == 0) + state_name = "none"; + + if (*ppos != 0) + return 0; + + cnt = snprintf(buf, sizeof(buf), "%s\n", state_name); + + return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt); +} + +static ssize_t pinctrl_state_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) +{ + int err; + char *s; + char state_name[64]; + struct seq_file *sfile; + struct pinctrl *p; + struct pinctrl_state *state; + struct pinctrl_state_helper_priv *priv; + + if (cnt > 63) { + pr_debug("%s: cnt TRUNCATED to 63", __func__); + cnt = 63; + } + + if (copy_from_user(state_name, ubuf, cnt)) { + pr_debug("%s: return -EFAULT", __func__); + return -EFAULT; + } + + state_name[cnt] = '\0'; + s = strchr(state_name, '\n'); + if (s != NULL) + *s = '\0'; + + sfile = file->private_data; + priv = sfile->private; + strncpy(priv->selected_state_name, state_name, 64); + + p = devm_pinctrl_get(priv->dev); + + state = pinctrl_lookup_state(p, state_name); + + if (!IS_ERR(state)) { + err = pinctrl_select_state(p, state); + if (err != 0) { + pr_err("Failed to select state %s\n", state_name); + return -EINVAL; + } + } else { + err = PTR_ERR_OR_ZERO(state); + pr_err("Failed to find state %s err=%d\n", state_name, err); + return -EINVAL; + } + + if (*ppos != 0) { + pr_err("%s: ppos not zero, return -EINVAL", __func__); + return -EINVAL; + } + + return cnt; +} + +static int pinctrl_state_open(struct inode *inode, struct file *file) +{ + return single_open(file, NULL, inode->i_private); +} + +static const struct file_operations pinctrl_state_ops = { + .owner = THIS_MODULE, + .open = pinctrl_state_open, + .read = pinctrl_state_read, + .write = pinctrl_state_write, + .llseek = no_llseek, + .release = single_release, +}; + +static int pinctrl_state_helper_probe(struct platform_device *pdev) +{ + struct pinctrl_state *state; + char *state_name = "default"; + struct pinctrl_state_helper_priv *priv; + struct device *dev = &pdev->dev; + int err; + struct dentry *pin_dentry; + struct dentry *helper_dir; + struct dentry *parent = NULL; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (priv == NULL) { + dev_err(&pdev->dev, "Failed to allocate priv\n"); + err = -ENOMEM; + goto err_no_mem; + } + + state_name = devm_kzalloc(&pdev->dev, strlen(PINCTRL_STATE_DEFAULT) + 1, + GFP_KERNEL); + if (state_name == NULL) { + dev_err(dev, "Failed to allocate state name\n"); + err = -ENOMEM; + goto err_no_state_mem; + } + strcpy(priv->selected_state_name, PINCTRL_STATE_DEFAULT); + platform_set_drvdata(pdev, priv); + + priv->pinctrl = devm_pinctrl_get(dev); + if (IS_ERR(priv->pinctrl)) { + dev_err(dev, "Failed to get pinctrl\n"); + err = PTR_ERR_OR_ZERO(priv->pinctrl); + goto err_no_pinctrl; + } + + if (err != 0) { + state = pinctrl_lookup_state(priv->pinctrl, + priv->selected_state_name); + if (!IS_ERR(state)) { + err = pinctrl_select_state(priv->pinctrl, state); + if (err != 0) { + dev_err(dev, "Failed to select default state\n"); + goto err_no_state; + } + } else { + *priv->selected_state_name = '\0'; + } + } + + helper_dir = debugfs_create_dir(dev_name(dev), parent); + priv->dev = dev; + pin_dentry = debugfs_create_file("state", 0600, helper_dir, priv, &pinctrl_state_ops); + + return 0; + +err_no_state: + devm_pinctrl_put(priv->pinctrl); +err_no_pinctrl: + devm_kfree(dev, priv->selected_state_name); +err_no_state_mem: + devm_kfree(dev, priv); +err_no_mem: + return err; +} + +static int pinctrl_state_helper_remove(struct platform_device *pdev) +{ + struct pinctrl_state_helper_priv *priv; + + priv = platform_get_drvdata(pdev); + devm_pinctrl_put(priv->pinctrl); + return 0; +} + +static const struct of_device_id helper_of_match[] = { + { + .compatible = "pinctrl,state-helper", + }, + { }, +}; +MODULE_DEVICE_TABLE(of, helper_of_match); + +static struct platform_driver pinctrl_state_helper_driver = { + .probe = pinctrl_state_helper_probe, + .remove = pinctrl_state_helper_remove, + .driver = { + .name = "pinctrl_state_helper", + .owner = THIS_MODULE, + .of_match_table = helper_of_match, + }, +}; + +module_platform_driver(pinctrl_state_helper_driver); + +MODULE_AUTHOR("Drew Fustini <drew@beagleboard.org>"); +MODULE_DESCRIPTION("One-register-per-pin type device tree based pinctrl driver"); +MODULE_LICENSE("GPL v2");

[RFC] pinctrl: add helper to expose pinctrl state in debugfs

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