// SPDX-License-Identifier: GPL-2.0
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/*
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* cpu vf test module
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* Copyright (C) 2019 frank@allwinnertech.com
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*/
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#include <linux/device.h>
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/regulator/consumer.h>
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struct vf_dev {
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struct regulator *cpu_reg;
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struct clk *cpu_clk;
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} vf_dev;
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static ssize_t volt_show(struct class *class, struct class_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%d\n", regulator_get_voltage(vf_dev.cpu_reg));
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}
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static ssize_t volt_store(struct class *class, struct class_attribute *attr,
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const char *buf, size_t count)
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{
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int volt;
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int ret;
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ret = kstrtoint(buf, 10, &volt);
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if (ret)
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return -EINVAL;
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regulator_set_voltage(vf_dev.cpu_reg, volt, volt);
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return count;
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}
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static ssize_t freq_show(struct class *class, struct class_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%lu\n", clk_get_rate(vf_dev.cpu_clk));
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}
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static ssize_t freq_store(struct class *class, struct class_attribute *attr,
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const char *buf, size_t count)
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{
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int freq;
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int ret;
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ret = kstrtoint(buf, 10, &freq);
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if (ret)
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return -EINVAL;
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clk_set_rate(vf_dev.cpu_clk, freq);
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return count;
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}
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static struct class_attribute vf_class_attrs[] = {
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__ATTR(cpu_volt, S_IWUSR | S_IRUGO, volt_show, volt_store),
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__ATTR(cpu_freq, S_IWUSR | S_IRUGO, freq_show, freq_store),
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__ATTR_NULL,
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};
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static struct class vf_class = {
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.name = "vf_table",
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.class_attrs = vf_class_attrs,
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};
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/*
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* An earlier version of opp-v1 bindings used to name the regulator
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* "cpu0-supply", we still need to handle that for backwards compatibility.
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*/
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static const char *find_supply_name(struct device *dev)
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{
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struct device_node *np;
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struct property *pp;
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int cpu = dev->id;
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const char *name = NULL;
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np = of_node_get(dev->of_node);
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/* This must be valid for sure */
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if (WARN_ON(!np))
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return NULL;
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/* Try "cpu0" for older DTs */
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if (!cpu) {
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pp = of_find_property(np, "cpu0-supply", NULL);
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if (pp) {
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name = "cpu0";
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goto node_put;
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}
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}
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pp = of_find_property(np, "cpu-supply", NULL);
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if (pp) {
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name = "cpu";
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goto node_put;
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}
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dev_dbg(dev, "no regulator for cpu%d\n", cpu);
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node_put:
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of_node_put(np);
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return name;
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}
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static int resources_available(void)
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{
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struct device *cpu_dev;
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int ret = 0;
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const char *name;
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cpu_dev = get_cpu_device(0);
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if (!cpu_dev) {
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pr_err("failed to get cpu0 device\n");
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return -ENODEV;
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}
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vf_dev.cpu_clk = clk_get(cpu_dev, NULL);
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ret = PTR_ERR_OR_ZERO(vf_dev.cpu_clk);
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if (ret) {
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/*
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* If cpu's clk node is present, but clock is not yet
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* registered, we should try defering probe.
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*/
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if (ret == -EPROBE_DEFER)
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dev_dbg(cpu_dev, "clock not ready, retry\n");
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else
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dev_err(cpu_dev, "failed to get clock: %d\n", ret);
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return ret;
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}
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name = find_supply_name(cpu_dev);
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/* Platform doesn't require regulator */
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if (!name)
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return 0;
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vf_dev.cpu_reg = regulator_get_optional(cpu_dev, name);
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ret = PTR_ERR_OR_ZERO(vf_dev.cpu_reg);
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if (ret) {
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/*
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* If cpu's regulator supply node is present, but regulator is
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* not yet registered, we should try defering probe.
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*/
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if (ret == -EPROBE_DEFER)
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dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
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else
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dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
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return ret;
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}
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return 0;
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}
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static int __init vf_init(void)
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{
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int ret;
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ret = resources_available();
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if (ret)
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return ret;
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return class_register(&vf_class);
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}
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module_init(vf_init);
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MODULE_LICENSE("GPL");
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