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307 lines
7.6 KiB
307 lines
7.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) STMicroelectronics 2017 |
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* |
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* Author: Fabrice Gasnier <[email protected]> |
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*/ |
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#include <linux/bitfield.h> |
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#include <linux/clk.h> |
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#include <linux/io.h> |
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#include <linux/iopoll.h> |
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#include <linux/module.h> |
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#include <linux/of_device.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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#include <linux/pm_runtime.h> |
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/* STM32 VREFBUF registers */ |
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#define STM32_VREFBUF_CSR 0x00 |
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/* STM32 VREFBUF CSR bitfields */ |
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#define STM32_VRS GENMASK(6, 4) |
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#define STM32_VRR BIT(3) |
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#define STM32_HIZ BIT(1) |
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#define STM32_ENVR BIT(0) |
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#define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10 |
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struct stm32_vrefbuf { |
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void __iomem *base; |
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struct clk *clk; |
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struct device *dev; |
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}; |
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static const unsigned int stm32_vrefbuf_voltages[] = { |
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/* Matches resp. VRS = 000b, 001b, 010b, 011b */ |
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2500000, 2048000, 1800000, 1500000, |
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}; |
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static int stm32_vrefbuf_enable(struct regulator_dev *rdev) |
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{ |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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u32 val; |
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int ret; |
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ret = pm_runtime_get_sync(priv->dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(priv->dev); |
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return ret; |
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} |
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val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
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val = (val & ~STM32_HIZ) | STM32_ENVR; |
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writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
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/* |
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* Vrefbuf startup time depends on external capacitor: wait here for |
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* VRR to be set. That means output has reached expected value. |
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* ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as |
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* arbitrary timeout. |
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*/ |
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ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val, |
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val & STM32_VRR, 650, 10000); |
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if (ret) { |
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dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n"); |
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val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
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val = (val & ~STM32_ENVR) | STM32_HIZ; |
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writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
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} |
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pm_runtime_mark_last_busy(priv->dev); |
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pm_runtime_put_autosuspend(priv->dev); |
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return ret; |
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} |
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static int stm32_vrefbuf_disable(struct regulator_dev *rdev) |
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{ |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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u32 val; |
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int ret; |
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ret = pm_runtime_get_sync(priv->dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(priv->dev); |
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return ret; |
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} |
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val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
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val &= ~STM32_ENVR; |
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writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
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pm_runtime_mark_last_busy(priv->dev); |
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pm_runtime_put_autosuspend(priv->dev); |
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return 0; |
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} |
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static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev) |
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{ |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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int ret; |
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ret = pm_runtime_get_sync(priv->dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(priv->dev); |
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return ret; |
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} |
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ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR; |
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pm_runtime_mark_last_busy(priv->dev); |
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pm_runtime_put_autosuspend(priv->dev); |
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return ret; |
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} |
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static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev, |
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unsigned sel) |
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{ |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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u32 val; |
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int ret; |
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ret = pm_runtime_get_sync(priv->dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(priv->dev); |
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return ret; |
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} |
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val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
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val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel); |
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writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
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pm_runtime_mark_last_busy(priv->dev); |
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pm_runtime_put_autosuspend(priv->dev); |
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return 0; |
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} |
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static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev) |
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{ |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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u32 val; |
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int ret; |
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ret = pm_runtime_get_sync(priv->dev); |
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if (ret < 0) { |
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pm_runtime_put_noidle(priv->dev); |
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return ret; |
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} |
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val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
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ret = FIELD_GET(STM32_VRS, val); |
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pm_runtime_mark_last_busy(priv->dev); |
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pm_runtime_put_autosuspend(priv->dev); |
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return ret; |
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} |
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static const struct regulator_ops stm32_vrefbuf_volt_ops = { |
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.enable = stm32_vrefbuf_enable, |
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.disable = stm32_vrefbuf_disable, |
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.is_enabled = stm32_vrefbuf_is_enabled, |
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.get_voltage_sel = stm32_vrefbuf_get_voltage_sel, |
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.set_voltage_sel = stm32_vrefbuf_set_voltage_sel, |
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.list_voltage = regulator_list_voltage_table, |
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}; |
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static const struct regulator_desc stm32_vrefbuf_regu = { |
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.name = "vref", |
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.supply_name = "vdda", |
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.volt_table = stm32_vrefbuf_voltages, |
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.n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), |
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.ops = &stm32_vrefbuf_volt_ops, |
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.off_on_delay = 1000, |
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.type = REGULATOR_VOLTAGE, |
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.owner = THIS_MODULE, |
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}; |
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static int stm32_vrefbuf_probe(struct platform_device *pdev) |
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{ |
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struct stm32_vrefbuf *priv; |
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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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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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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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priv->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(priv->clk)) |
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return PTR_ERR(priv->clk); |
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pm_runtime_get_noresume(&pdev->dev); |
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pm_runtime_set_active(&pdev->dev); |
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pm_runtime_set_autosuspend_delay(&pdev->dev, |
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STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS); |
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pm_runtime_use_autosuspend(&pdev->dev); |
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pm_runtime_enable(&pdev->dev); |
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ret = clk_prepare_enable(priv->clk); |
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if (ret) { |
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dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret); |
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goto err_pm_stop; |
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} |
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config.dev = &pdev->dev; |
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config.driver_data = priv; |
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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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&stm32_vrefbuf_regu); |
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rdev = regulator_register(&stm32_vrefbuf_regu, &config); |
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if (IS_ERR(rdev)) { |
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ret = PTR_ERR(rdev); |
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dev_err(&pdev->dev, "register failed with error %d\n", ret); |
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goto err_clk_dis; |
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} |
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platform_set_drvdata(pdev, rdev); |
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pm_runtime_mark_last_busy(&pdev->dev); |
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pm_runtime_put_autosuspend(&pdev->dev); |
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return 0; |
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err_clk_dis: |
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clk_disable_unprepare(priv->clk); |
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err_pm_stop: |
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pm_runtime_disable(&pdev->dev); |
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pm_runtime_set_suspended(&pdev->dev); |
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pm_runtime_put_noidle(&pdev->dev); |
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return ret; |
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} |
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static int stm32_vrefbuf_remove(struct platform_device *pdev) |
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{ |
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struct regulator_dev *rdev = platform_get_drvdata(pdev); |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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pm_runtime_get_sync(&pdev->dev); |
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regulator_unregister(rdev); |
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clk_disable_unprepare(priv->clk); |
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pm_runtime_disable(&pdev->dev); |
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pm_runtime_set_suspended(&pdev->dev); |
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pm_runtime_put_noidle(&pdev->dev); |
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return 0; |
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}; |
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static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev) |
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{ |
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struct regulator_dev *rdev = dev_get_drvdata(dev); |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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clk_disable_unprepare(priv->clk); |
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return 0; |
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} |
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static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev) |
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{ |
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struct regulator_dev *rdev = dev_get_drvdata(dev); |
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struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
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return clk_prepare_enable(priv->clk); |
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} |
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static const struct dev_pm_ops stm32_vrefbuf_pm_ops = { |
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SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, |
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pm_runtime_force_resume) |
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SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend, |
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stm32_vrefbuf_runtime_resume, |
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NULL) |
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}; |
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static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = { |
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{ .compatible = "st,stm32-vrefbuf", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match); |
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static struct platform_driver stm32_vrefbuf_driver = { |
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.probe = stm32_vrefbuf_probe, |
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.remove = stm32_vrefbuf_remove, |
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.driver = { |
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.name = "stm32-vrefbuf", |
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.of_match_table = of_match_ptr(stm32_vrefbuf_of_match), |
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.pm = &stm32_vrefbuf_pm_ops, |
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}, |
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}; |
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module_platform_driver(stm32_vrefbuf_driver); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_AUTHOR("Fabrice Gasnier <[email protected]>"); |
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MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver"); |
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MODULE_ALIAS("platform:stm32-vrefbuf");
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