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Probing of regulators can be a slow operation and can contribute to slower boot times. This is especially true if a regulator is turned on at probe time (with regulator-boot-on or regulator-always-on) and the regulator requires delays (off-on-time, ramp time, etc). While the overall kernel is not ready to switch to async probe by default, as per the discussion on the mailing lists [1] it is believed that the regulator subsystem is in good shape and we can move regulator drivers over wholesale. There is no way to just magically opt in all regulators (regulators are just normal drivers like platform_driver), so we set PROBE_PREFER_ASYNCHRONOUS for all regulators found in 'drivers/regulator' individually. Given the number of drivers touched and the impossibility to test this ahead of time, it wouldn't be shocking at all if this caused a regression for someone. If there is a regression caused by this patch, it's likely to be one of the cases talked about in [1]. As a "quick fix", drivers involved in the regression could be fixed by changing them to PROBE_FORCE_SYNCHRONOUS. That being said, the correct fix would be to directly fix the problem that caused the issue with async probe. The approach here follows a similar approach that was used for the mmc subsystem several years ago [2]. In fact, I ran nearly the same python script to auto-generate the changes. The only thing I changed was to search for "i2c_driver", "spmi_driver", and "spi_driver" in addition to "platform_driver". [1] https://lore.kernel.org/r/06db017f-e985-4434-8d1d-02ca2100cca0@sirena.org.uk [2] https://lore.kernel.org/r/20200903232441.2694866-1-dianders@chromium.org/ Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20230316125351.1.I2a4677392a38db5758dee0788b2cea5872562a82@changeid Signed-off-by: Mark Brown <broonie@kernel.org>
92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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// sky81452-regulator.c SKY81452 regulator driver
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//
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// Copyright 2014 Skyworks Solutions Inc.
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// Author : Gyungoh Yoo <jack.yoo@skyworksinc.com>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/of_regulator.h>
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/* registers */
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#define SKY81452_REG1 0x01
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#define SKY81452_REG3 0x03
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/* bit mask */
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#define SKY81452_LEN 0x40
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#define SKY81452_LOUT 0x1F
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static const struct regulator_ops sky81452_reg_ops = {
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.list_voltage = regulator_list_voltage_linear_range,
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.map_voltage = regulator_map_voltage_linear_range,
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.get_voltage_sel = regulator_get_voltage_sel_regmap,
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.set_voltage_sel = regulator_set_voltage_sel_regmap,
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.enable = regulator_enable_regmap,
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.disable = regulator_disable_regmap,
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.is_enabled = regulator_is_enabled_regmap,
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};
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static const struct linear_range sky81452_reg_ranges[] = {
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REGULATOR_LINEAR_RANGE(4500000, 0, 14, 250000),
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REGULATOR_LINEAR_RANGE(9000000, 15, 31, 1000000),
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};
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static const struct regulator_desc sky81452_reg = {
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.name = "LOUT",
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.of_match = of_match_ptr("lout"),
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.regulators_node = of_match_ptr("regulator"),
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.ops = &sky81452_reg_ops,
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.type = REGULATOR_VOLTAGE,
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.owner = THIS_MODULE,
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.n_voltages = SKY81452_LOUT + 1,
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.linear_ranges = sky81452_reg_ranges,
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.n_linear_ranges = ARRAY_SIZE(sky81452_reg_ranges),
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.vsel_reg = SKY81452_REG3,
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.vsel_mask = SKY81452_LOUT,
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.enable_reg = SKY81452_REG1,
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.enable_mask = SKY81452_LEN,
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};
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static int sky81452_reg_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct regulator_init_data *init_data = dev_get_platdata(dev);
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struct regulator_config config = { };
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struct regulator_dev *rdev;
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config.dev = dev->parent;
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config.init_data = init_data;
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config.of_node = dev->of_node;
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config.regmap = dev_get_drvdata(dev->parent);
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rdev = devm_regulator_register(dev, &sky81452_reg, &config);
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if (IS_ERR(rdev)) {
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dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(rdev));
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return PTR_ERR(rdev);
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}
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platform_set_drvdata(pdev, rdev);
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return 0;
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}
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static struct platform_driver sky81452_reg_driver = {
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.driver = {
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.name = "sky81452-regulator",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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},
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.probe = sky81452_reg_probe,
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};
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module_platform_driver(sky81452_reg_driver);
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MODULE_DESCRIPTION("Skyworks SKY81452 Regulator driver");
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MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
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MODULE_LICENSE("GPL v2");
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