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259b93b21a
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>
105 lines
2.7 KiB
C
105 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Regulator driver for STw4810/STw4811 VMMC regulator.
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*
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* Copyright (C) 2013 ST-Ericsson SA
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* Written on behalf of Linaro for ST-Ericsson
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*
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* Author: Linus Walleij <linus.walleij@linaro.org>
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*/
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/mfd/stw481x.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/of_regulator.h>
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static const unsigned int stw481x_vmmc_voltages[] = {
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1800000,
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1800000,
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2850000,
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3000000,
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1850000,
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2600000,
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2700000,
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3300000,
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};
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static const struct regulator_ops stw481x_vmmc_ops = {
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.list_voltage = regulator_list_voltage_table,
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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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.get_voltage_sel = regulator_get_voltage_sel_regmap,
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.set_voltage_sel = regulator_set_voltage_sel_regmap,
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};
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static const struct regulator_desc vmmc_regulator = {
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.name = "VMMC",
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.id = 0,
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.ops = &stw481x_vmmc_ops,
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.type = REGULATOR_VOLTAGE,
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.owner = THIS_MODULE,
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.n_voltages = ARRAY_SIZE(stw481x_vmmc_voltages),
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.volt_table = stw481x_vmmc_voltages,
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.enable_time = 200, /* FIXME: look this up */
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.enable_reg = STW_CONF1,
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.enable_mask = STW_CONF1_PDN_VMMC | STW_CONF1_MMC_LS_STATUS,
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.enable_val = STW_CONF1_PDN_VMMC,
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.vsel_reg = STW_CONF1,
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.vsel_mask = STW_CONF1_VMMC_MASK,
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};
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static int stw481x_vmmc_regulator_probe(struct platform_device *pdev)
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{
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struct stw481x *stw481x = dev_get_platdata(&pdev->dev);
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struct regulator_config config = { };
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struct regulator_dev *rdev;
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int ret;
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/* First disable the external VMMC if it's active */
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ret = regmap_update_bits(stw481x->map, STW_CONF2,
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STW_CONF2_VMMC_EXT, 0);
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if (ret) {
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dev_err(&pdev->dev, "could not disable external VMMC\n");
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return ret;
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}
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/* Register VMMC regulator */
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config.dev = &pdev->dev;
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config.driver_data = stw481x;
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config.regmap = stw481x->map;
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config.of_node = pdev->dev.of_node;
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config.init_data = of_get_regulator_init_data(&pdev->dev,
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pdev->dev.of_node,
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&vmmc_regulator);
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rdev = devm_regulator_register(&pdev->dev, &vmmc_regulator, &config);
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if (IS_ERR(rdev)) {
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dev_err(&pdev->dev,
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"error initializing STw481x VMMC regulator\n");
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return PTR_ERR(rdev);
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}
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dev_info(&pdev->dev, "initialized STw481x VMMC regulator\n");
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return 0;
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}
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static const struct of_device_id stw481x_vmmc_match[] = {
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{ .compatible = "st,stw481x-vmmc", },
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{},
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};
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static struct platform_driver stw481x_vmmc_regulator_driver = {
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.driver = {
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.name = "stw481x-vmmc-regulator",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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.of_match_table = stw481x_vmmc_match,
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},
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.probe = stw481x_vmmc_regulator_probe,
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};
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module_platform_driver(stw481x_vmmc_regulator_driver);
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