drivers/regulator/stm32-vrefbuf.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) STMicroelectronics 2017
0004  *
0005  * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
0006  */
0007
0008 #include <linux/bitfield.h>
0009 #include <linux/clk.h>
0010 #include <linux/io.h>
0011 #include <linux/iopoll.h>
0012 #include <linux/module.h>
0013 #include <linux/of_device.h>
0014 #include <linux/platform_device.h>
0015 #include <linux/regulator/driver.h>
0016 #include <linux/regulator/of_regulator.h>
0017 #include <linux/pm_runtime.h>
0018
0019 /* STM32 VREFBUF registers */
0020 #define STM32_VREFBUF_CSR       0x00
0021
0022 /* STM32 VREFBUF CSR bitfields */
0023 #define STM32_VRS           GENMASK(6, 4)
0024 #define STM32_VRR           BIT(3)
0025 #define STM32_HIZ           BIT(1)
0026 #define STM32_ENVR          BIT(0)
0027
0028 #define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10
0029
0030 struct stm32_vrefbuf {
0031     void __iomem *base;
0032     struct clk *clk;
0033     struct device *dev;
0034 };
0035
0036 static const unsigned int stm32_vrefbuf_voltages[] = {
0037     /* Matches resp. VRS = 000b, 001b, 010b, 011b */
0038     2500000, 2048000, 1800000, 1500000,
0039 };
0040
0041 static int stm32_vrefbuf_enable(struct regulator_dev *rdev)
0042 {
0043     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0044     u32 val;
0045     int ret;
0046
0047     ret = pm_runtime_resume_and_get(priv->dev);
0048     if (ret < 0)
0049         return ret;
0050
0051     val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
0052     val = (val & ~STM32_HIZ) | STM32_ENVR;
0053     writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
0054
0055     /*
0056      * Vrefbuf startup time depends on external capacitor: wait here for
0057      * VRR to be set. That means output has reached expected value.
0058      * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as
0059      * arbitrary timeout.
0060      */
0061     ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val,
0062                  val & STM32_VRR, 650, 10000);
0063     if (ret) {
0064         dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n");
0065         val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
0066         val = (val & ~STM32_ENVR) | STM32_HIZ;
0067         writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
0068     }
0069
0070     pm_runtime_mark_last_busy(priv->dev);
0071     pm_runtime_put_autosuspend(priv->dev);
0072
0073     return ret;
0074 }
0075
0076 static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
0077 {
0078     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0079     u32 val;
0080     int ret;
0081
0082     ret = pm_runtime_resume_and_get(priv->dev);
0083     if (ret < 0)
0084         return ret;
0085
0086     val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
0087     val &= ~STM32_ENVR;
0088     writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
0089
0090     pm_runtime_mark_last_busy(priv->dev);
0091     pm_runtime_put_autosuspend(priv->dev);
0092
0093     return 0;
0094 }
0095
0096 static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev)
0097 {
0098     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0099     int ret;
0100
0101     ret = pm_runtime_resume_and_get(priv->dev);
0102     if (ret < 0)
0103         return ret;
0104
0105     ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;
0106
0107     pm_runtime_mark_last_busy(priv->dev);
0108     pm_runtime_put_autosuspend(priv->dev);
0109
0110     return ret;
0111 }
0112
0113 static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev,
0114                      unsigned sel)
0115 {
0116     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0117     u32 val;
0118     int ret;
0119
0120     ret = pm_runtime_resume_and_get(priv->dev);
0121     if (ret < 0)
0122         return ret;
0123
0124     val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
0125     val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel);
0126     writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
0127
0128     pm_runtime_mark_last_busy(priv->dev);
0129     pm_runtime_put_autosuspend(priv->dev);
0130
0131     return 0;
0132 }
0133
0134 static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev)
0135 {
0136     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0137     u32 val;
0138     int ret;
0139
0140     ret = pm_runtime_resume_and_get(priv->dev);
0141     if (ret < 0)
0142         return ret;
0143
0144     val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
0145     ret = FIELD_GET(STM32_VRS, val);
0146
0147     pm_runtime_mark_last_busy(priv->dev);
0148     pm_runtime_put_autosuspend(priv->dev);
0149
0150     return ret;
0151 }
0152
0153 static const struct regulator_ops stm32_vrefbuf_volt_ops = {
0154     .enable     = stm32_vrefbuf_enable,
0155     .disable    = stm32_vrefbuf_disable,
0156     .is_enabled = stm32_vrefbuf_is_enabled,
0157     .get_voltage_sel = stm32_vrefbuf_get_voltage_sel,
0158     .set_voltage_sel = stm32_vrefbuf_set_voltage_sel,
0159     .list_voltage   = regulator_list_voltage_table,
0160 };
0161
0162 static const struct regulator_desc stm32_vrefbuf_regu = {
0163     .name = "vref",
0164     .supply_name = "vdda",
0165     .volt_table = stm32_vrefbuf_voltages,
0166     .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
0167     .ops = &stm32_vrefbuf_volt_ops,
0168     .off_on_delay = 1000,
0169     .type = REGULATOR_VOLTAGE,
0170     .owner = THIS_MODULE,
0171 };
0172
0173 static int stm32_vrefbuf_probe(struct platform_device *pdev)
0174 {
0175     struct stm32_vrefbuf *priv;
0176     struct regulator_config config = { };
0177     struct regulator_dev *rdev;
0178     int ret;
0179
0180     priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
0181     if (!priv)
0182         return -ENOMEM;
0183     priv->dev = &pdev->dev;
0184
0185     priv->base = devm_platform_ioremap_resource(pdev, 0);
0186     if (IS_ERR(priv->base))
0187         return PTR_ERR(priv->base);
0188
0189     priv->clk = devm_clk_get(&pdev->dev, NULL);
0190     if (IS_ERR(priv->clk))
0191         return PTR_ERR(priv->clk);
0192
0193     pm_runtime_get_noresume(&pdev->dev);
0194     pm_runtime_set_active(&pdev->dev);
0195     pm_runtime_set_autosuspend_delay(&pdev->dev,
0196                      STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS);
0197     pm_runtime_use_autosuspend(&pdev->dev);
0198     pm_runtime_enable(&pdev->dev);
0199
0200     ret = clk_prepare_enable(priv->clk);
0201     if (ret) {
0202         dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret);
0203         goto err_pm_stop;
0204     }
0205
0206     config.dev = &pdev->dev;
0207     config.driver_data = priv;
0208     config.of_node = pdev->dev.of_node;
0209     config.init_data = of_get_regulator_init_data(&pdev->dev,
0210                               pdev->dev.of_node,
0211                               &stm32_vrefbuf_regu);
0212
0213     rdev = regulator_register(&stm32_vrefbuf_regu, &config);
0214     if (IS_ERR(rdev)) {
0215         ret = PTR_ERR(rdev);
0216         dev_err(&pdev->dev, "register failed with error %d\n", ret);
0217         goto err_clk_dis;
0218     }
0219     platform_set_drvdata(pdev, rdev);
0220
0221     pm_runtime_mark_last_busy(&pdev->dev);
0222     pm_runtime_put_autosuspend(&pdev->dev);
0223
0224     return 0;
0225
0226 err_clk_dis:
0227     clk_disable_unprepare(priv->clk);
0228 err_pm_stop:
0229     pm_runtime_disable(&pdev->dev);
0230     pm_runtime_set_suspended(&pdev->dev);
0231     pm_runtime_put_noidle(&pdev->dev);
0232
0233     return ret;
0234 }
0235
0236 static int stm32_vrefbuf_remove(struct platform_device *pdev)
0237 {
0238     struct regulator_dev *rdev = platform_get_drvdata(pdev);
0239     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0240
0241     pm_runtime_get_sync(&pdev->dev);
0242     regulator_unregister(rdev);
0243     clk_disable_unprepare(priv->clk);
0244     pm_runtime_disable(&pdev->dev);
0245     pm_runtime_set_suspended(&pdev->dev);
0246     pm_runtime_put_noidle(&pdev->dev);
0247
0248     return 0;
0249 };
0250
0251 static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev)
0252 {
0253     struct regulator_dev *rdev = dev_get_drvdata(dev);
0254     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0255
0256     clk_disable_unprepare(priv->clk);
0257
0258     return 0;
0259 }
0260
0261 static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev)
0262 {
0263     struct regulator_dev *rdev = dev_get_drvdata(dev);
0264     struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
0265
0266     return clk_prepare_enable(priv->clk);
0267 }
0268
0269 static const struct dev_pm_ops stm32_vrefbuf_pm_ops = {
0270     SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
0271                 pm_runtime_force_resume)
0272     SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend,
0273                stm32_vrefbuf_runtime_resume,
0274                NULL)
0275 };
0276
0277 static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = {
0278     { .compatible = "st,stm32-vrefbuf", },
0279     {},
0280 };
0281 MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match);
0282
0283 static struct platform_driver stm32_vrefbuf_driver = {
0284     .probe = stm32_vrefbuf_probe,
0285     .remove = stm32_vrefbuf_remove,
0286     .driver = {
0287         .name  = "stm32-vrefbuf",
0288         .of_match_table = of_match_ptr(stm32_vrefbuf_of_match),
0289         .pm = &stm32_vrefbuf_pm_ops,
0290     },
0291 };
0292 module_platform_driver(stm32_vrefbuf_driver);
0293
0294 MODULE_LICENSE("GPL v2");
0295 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
0296 MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver");
0297 MODULE_ALIAS("platform:stm32-vrefbuf");