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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> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
203 lines
4.8 KiB
C
203 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
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*
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* Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/cpufreq.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <asm/proc-fns.h>
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#define CPU_SW_INT_BLK BIT(28)
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static struct priv
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{
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struct clk *cpu_clk;
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struct clk *ddr_clk;
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struct clk *powersave_clk;
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struct device *dev;
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void __iomem *base;
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} priv;
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#define STATE_CPU_FREQ 0x01
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#define STATE_DDR_FREQ 0x02
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/*
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* Kirkwood can swap the clock to the CPU between two clocks:
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*
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* - cpu clk
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* - ddr clk
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*
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* The frequencies are set at runtime before registering this table.
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*/
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static struct cpufreq_frequency_table kirkwood_freq_table[] = {
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{0, STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */
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{0, STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */
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{0, 0, CPUFREQ_TABLE_END},
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};
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static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
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{
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return clk_get_rate(priv.powersave_clk) / 1000;
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}
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static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int index)
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{
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unsigned int state = kirkwood_freq_table[index].driver_data;
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unsigned long reg;
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local_irq_disable();
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/* Disable interrupts to the CPU */
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reg = readl_relaxed(priv.base);
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reg |= CPU_SW_INT_BLK;
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writel_relaxed(reg, priv.base);
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switch (state) {
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case STATE_CPU_FREQ:
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clk_set_parent(priv.powersave_clk, priv.cpu_clk);
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break;
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case STATE_DDR_FREQ:
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clk_set_parent(priv.powersave_clk, priv.ddr_clk);
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break;
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}
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/* Wait-for-Interrupt, while the hardware changes frequency */
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cpu_do_idle();
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/* Enable interrupts to the CPU */
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reg = readl_relaxed(priv.base);
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reg &= ~CPU_SW_INT_BLK;
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writel_relaxed(reg, priv.base);
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local_irq_enable();
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return 0;
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}
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/* Module init and exit code */
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static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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cpufreq_generic_init(policy, kirkwood_freq_table, 5000);
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return 0;
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}
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static struct cpufreq_driver kirkwood_cpufreq_driver = {
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.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
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.get = kirkwood_cpufreq_get_cpu_frequency,
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = kirkwood_cpufreq_target,
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.init = kirkwood_cpufreq_cpu_init,
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.name = "kirkwood-cpufreq",
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.attr = cpufreq_generic_attr,
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};
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static int kirkwood_cpufreq_probe(struct platform_device *pdev)
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{
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struct device_node *np;
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int err;
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priv.dev = &pdev->dev;
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priv.base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(priv.base))
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return PTR_ERR(priv.base);
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np = of_cpu_device_node_get(0);
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if (!np) {
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dev_err(&pdev->dev, "failed to get cpu device node\n");
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return -ENODEV;
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}
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priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
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if (IS_ERR(priv.cpu_clk)) {
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dev_err(priv.dev, "Unable to get cpuclk\n");
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err = PTR_ERR(priv.cpu_clk);
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goto out_node;
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}
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err = clk_prepare_enable(priv.cpu_clk);
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if (err) {
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dev_err(priv.dev, "Unable to prepare cpuclk\n");
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goto out_node;
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}
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kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;
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priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
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if (IS_ERR(priv.ddr_clk)) {
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dev_err(priv.dev, "Unable to get ddrclk\n");
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err = PTR_ERR(priv.ddr_clk);
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goto out_cpu;
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}
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err = clk_prepare_enable(priv.ddr_clk);
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if (err) {
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dev_err(priv.dev, "Unable to prepare ddrclk\n");
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goto out_cpu;
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}
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kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;
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priv.powersave_clk = of_clk_get_by_name(np, "powersave");
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if (IS_ERR(priv.powersave_clk)) {
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dev_err(priv.dev, "Unable to get powersave\n");
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err = PTR_ERR(priv.powersave_clk);
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goto out_ddr;
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}
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err = clk_prepare_enable(priv.powersave_clk);
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if (err) {
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dev_err(priv.dev, "Unable to prepare powersave clk\n");
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goto out_ddr;
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}
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err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
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if (err) {
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dev_err(priv.dev, "Failed to register cpufreq driver\n");
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goto out_powersave;
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}
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of_node_put(np);
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return 0;
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out_powersave:
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clk_disable_unprepare(priv.powersave_clk);
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out_ddr:
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clk_disable_unprepare(priv.ddr_clk);
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out_cpu:
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clk_disable_unprepare(priv.cpu_clk);
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out_node:
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of_node_put(np);
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return err;
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}
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static void kirkwood_cpufreq_remove(struct platform_device *pdev)
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{
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cpufreq_unregister_driver(&kirkwood_cpufreq_driver);
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clk_disable_unprepare(priv.powersave_clk);
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clk_disable_unprepare(priv.ddr_clk);
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clk_disable_unprepare(priv.cpu_clk);
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}
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static struct platform_driver kirkwood_cpufreq_platform_driver = {
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.probe = kirkwood_cpufreq_probe,
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.remove_new = kirkwood_cpufreq_remove,
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.driver = {
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.name = "kirkwood-cpufreq",
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},
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};
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module_platform_driver(kirkwood_cpufreq_platform_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
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MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
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MODULE_ALIAS("platform:kirkwood-cpufreq");
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