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![Uwe Kleine-König](/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. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20230312161512.2715500-14-u.kleine-koenig@pengutronix.de Signed-off-by: Stephen Boyd <sboyd@kernel.org>
156 lines
3.5 KiB
C
156 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2014 Philipp Zabel, Pengutronix
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*
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* PWM (mis)used as clock output
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*/
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#include <linux/clk-provider.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/platform_device.h>
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#include <linux/pwm.h>
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struct clk_pwm {
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struct clk_hw hw;
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struct pwm_device *pwm;
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u32 fixed_rate;
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};
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static inline struct clk_pwm *to_clk_pwm(struct clk_hw *hw)
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{
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return container_of(hw, struct clk_pwm, hw);
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}
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static int clk_pwm_prepare(struct clk_hw *hw)
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{
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struct clk_pwm *clk_pwm = to_clk_pwm(hw);
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return pwm_enable(clk_pwm->pwm);
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}
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static void clk_pwm_unprepare(struct clk_hw *hw)
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{
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struct clk_pwm *clk_pwm = to_clk_pwm(hw);
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pwm_disable(clk_pwm->pwm);
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}
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static unsigned long clk_pwm_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct clk_pwm *clk_pwm = to_clk_pwm(hw);
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return clk_pwm->fixed_rate;
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}
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static int clk_pwm_get_duty_cycle(struct clk_hw *hw, struct clk_duty *duty)
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{
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struct clk_pwm *clk_pwm = to_clk_pwm(hw);
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struct pwm_state state;
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pwm_get_state(clk_pwm->pwm, &state);
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duty->num = state.duty_cycle;
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duty->den = state.period;
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return 0;
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}
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static const struct clk_ops clk_pwm_ops = {
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.prepare = clk_pwm_prepare,
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.unprepare = clk_pwm_unprepare,
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.recalc_rate = clk_pwm_recalc_rate,
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.get_duty_cycle = clk_pwm_get_duty_cycle,
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};
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static int clk_pwm_probe(struct platform_device *pdev)
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{
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struct device_node *node = pdev->dev.of_node;
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struct clk_init_data init;
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struct clk_pwm *clk_pwm;
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struct pwm_device *pwm;
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struct pwm_args pargs;
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const char *clk_name;
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int ret;
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clk_pwm = devm_kzalloc(&pdev->dev, sizeof(*clk_pwm), GFP_KERNEL);
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if (!clk_pwm)
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return -ENOMEM;
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pwm = devm_pwm_get(&pdev->dev, NULL);
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if (IS_ERR(pwm))
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return PTR_ERR(pwm);
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pwm_get_args(pwm, &pargs);
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if (!pargs.period) {
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dev_err(&pdev->dev, "invalid PWM period\n");
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return -EINVAL;
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}
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if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
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clk_pwm->fixed_rate = div64_u64(NSEC_PER_SEC, pargs.period);
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if (!clk_pwm->fixed_rate) {
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dev_err(&pdev->dev, "fixed_rate cannot be zero\n");
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return -EINVAL;
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}
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if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
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pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
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dev_err(&pdev->dev,
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"clock-frequency does not match PWM period\n");
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return -EINVAL;
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}
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/*
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* FIXME: pwm_apply_args() should be removed when switching to the
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* atomic PWM API.
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*/
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pwm_apply_args(pwm);
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ret = pwm_config(pwm, (pargs.period + 1) >> 1, pargs.period);
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if (ret < 0)
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return ret;
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clk_name = node->name;
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of_property_read_string(node, "clock-output-names", &clk_name);
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init.name = clk_name;
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init.ops = &clk_pwm_ops;
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init.flags = 0;
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init.num_parents = 0;
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clk_pwm->pwm = pwm;
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clk_pwm->hw.init = &init;
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ret = devm_clk_hw_register(&pdev->dev, &clk_pwm->hw);
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if (ret)
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return ret;
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return of_clk_add_hw_provider(node, of_clk_hw_simple_get, &clk_pwm->hw);
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}
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static void clk_pwm_remove(struct platform_device *pdev)
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{
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of_clk_del_provider(pdev->dev.of_node);
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}
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static const struct of_device_id clk_pwm_dt_ids[] = {
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{ .compatible = "pwm-clock" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, clk_pwm_dt_ids);
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static struct platform_driver clk_pwm_driver = {
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.probe = clk_pwm_probe,
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.remove_new = clk_pwm_remove,
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.driver = {
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.name = "pwm-clock",
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.of_match_table = clk_pwm_dt_ids,
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},
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};
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module_platform_driver(clk_pwm_driver);
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MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
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MODULE_DESCRIPTION("PWM clock driver");
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MODULE_LICENSE("GPL");
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