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![Yangtao Li](/assets/img/avatar_default.png)
The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Yangtao Li <frank.li@vivo.com> Acked-by: Jernej Škrabec <jernej.skrabec@gmail.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
217 lines
4.9 KiB
C
217 lines
4.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Allwinner CPUFreq nvmem based driver
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*
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* The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
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* provide the OPP framework with required information.
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*
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* Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/nvmem-consumer.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/pm_opp.h>
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#include <linux/slab.h>
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#define MAX_NAME_LEN 7
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#define NVMEM_MASK 0x7
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#define NVMEM_SHIFT 5
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static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
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/**
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* sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
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* @versions: Set to the value parsed from efuse
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*
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* Returns 0 if success.
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*/
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static int sun50i_cpufreq_get_efuse(u32 *versions)
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{
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struct nvmem_cell *speedbin_nvmem;
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struct device_node *np;
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struct device *cpu_dev;
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u32 *speedbin, efuse_value;
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size_t len;
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int ret;
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cpu_dev = get_cpu_device(0);
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if (!cpu_dev)
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return -ENODEV;
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np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
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if (!np)
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return -ENOENT;
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ret = of_device_is_compatible(np,
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"allwinner,sun50i-h6-operating-points");
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if (!ret) {
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of_node_put(np);
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return -ENOENT;
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}
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speedbin_nvmem = of_nvmem_cell_get(np, NULL);
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of_node_put(np);
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if (IS_ERR(speedbin_nvmem))
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return dev_err_probe(cpu_dev, PTR_ERR(speedbin_nvmem),
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"Could not get nvmem cell\n");
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speedbin = nvmem_cell_read(speedbin_nvmem, &len);
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nvmem_cell_put(speedbin_nvmem);
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if (IS_ERR(speedbin))
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return PTR_ERR(speedbin);
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efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
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/*
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* We treat unexpected efuse values as if the SoC was from
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* the slowest bin. Expected efuse values are 1-3, slowest
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* to fastest.
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*/
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if (efuse_value >= 1 && efuse_value <= 3)
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*versions = efuse_value - 1;
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else
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*versions = 0;
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kfree(speedbin);
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return 0;
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};
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static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
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{
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int *opp_tokens;
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char name[MAX_NAME_LEN];
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unsigned int cpu;
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u32 speed = 0;
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int ret;
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opp_tokens = kcalloc(num_possible_cpus(), sizeof(*opp_tokens),
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GFP_KERNEL);
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if (!opp_tokens)
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return -ENOMEM;
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ret = sun50i_cpufreq_get_efuse(&speed);
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if (ret) {
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kfree(opp_tokens);
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return ret;
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}
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snprintf(name, MAX_NAME_LEN, "speed%d", speed);
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for_each_possible_cpu(cpu) {
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struct device *cpu_dev = get_cpu_device(cpu);
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if (!cpu_dev) {
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ret = -ENODEV;
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goto free_opp;
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}
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opp_tokens[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
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if (opp_tokens[cpu] < 0) {
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ret = opp_tokens[cpu];
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pr_err("Failed to set prop name\n");
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goto free_opp;
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}
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}
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cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
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NULL, 0);
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if (!IS_ERR(cpufreq_dt_pdev)) {
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platform_set_drvdata(pdev, opp_tokens);
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return 0;
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}
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ret = PTR_ERR(cpufreq_dt_pdev);
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pr_err("Failed to register platform device\n");
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free_opp:
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for_each_possible_cpu(cpu)
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dev_pm_opp_put_prop_name(opp_tokens[cpu]);
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kfree(opp_tokens);
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return ret;
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}
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static void sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
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{
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int *opp_tokens = platform_get_drvdata(pdev);
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unsigned int cpu;
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platform_device_unregister(cpufreq_dt_pdev);
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for_each_possible_cpu(cpu)
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dev_pm_opp_put_prop_name(opp_tokens[cpu]);
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kfree(opp_tokens);
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}
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static struct platform_driver sun50i_cpufreq_driver = {
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.probe = sun50i_cpufreq_nvmem_probe,
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.remove_new = sun50i_cpufreq_nvmem_remove,
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.driver = {
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.name = "sun50i-cpufreq-nvmem",
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},
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};
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static const struct of_device_id sun50i_cpufreq_match_list[] = {
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{ .compatible = "allwinner,sun50i-h6" },
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{}
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};
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MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list);
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static const struct of_device_id *sun50i_cpufreq_match_node(void)
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{
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const struct of_device_id *match;
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struct device_node *np;
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np = of_find_node_by_path("/");
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match = of_match_node(sun50i_cpufreq_match_list, np);
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of_node_put(np);
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return match;
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}
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/*
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* Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
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* all the real activity is done in the probe, which may be defered as well.
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* The init here is only registering the driver and the platform device.
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*/
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static int __init sun50i_cpufreq_init(void)
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{
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const struct of_device_id *match;
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int ret;
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match = sun50i_cpufreq_match_node();
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if (!match)
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return -ENODEV;
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ret = platform_driver_register(&sun50i_cpufreq_driver);
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if (unlikely(ret < 0))
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return ret;
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sun50i_cpufreq_pdev =
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platform_device_register_simple("sun50i-cpufreq-nvmem",
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-1, NULL, 0);
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ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
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if (ret == 0)
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return 0;
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platform_driver_unregister(&sun50i_cpufreq_driver);
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return ret;
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}
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module_init(sun50i_cpufreq_init);
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static void __exit sun50i_cpufreq_exit(void)
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{
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platform_device_unregister(sun50i_cpufreq_pdev);
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platform_driver_unregister(&sun50i_cpufreq_driver);
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}
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module_exit(sun50i_cpufreq_exit);
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MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
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MODULE_LICENSE("GPL v2");
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