10cdbf481SFabrice Gasnier /* 20cdbf481SFabrice Gasnier * Copyright (C) STMicroelectronics 2017 30cdbf481SFabrice Gasnier * 40cdbf481SFabrice Gasnier * Author: Fabrice Gasnier <fabrice.gasnier@st.com> 50cdbf481SFabrice Gasnier * 60cdbf481SFabrice Gasnier * License terms: GNU General Public License (GPL), version 2 70cdbf481SFabrice Gasnier */ 80cdbf481SFabrice Gasnier 90cdbf481SFabrice Gasnier #include <linux/bitfield.h> 100cdbf481SFabrice Gasnier #include <linux/clk.h> 110cdbf481SFabrice Gasnier #include <linux/io.h> 120cdbf481SFabrice Gasnier #include <linux/iopoll.h> 130cdbf481SFabrice Gasnier #include <linux/module.h> 140cdbf481SFabrice Gasnier #include <linux/of_device.h> 150cdbf481SFabrice Gasnier #include <linux/platform_device.h> 160cdbf481SFabrice Gasnier #include <linux/regulator/driver.h> 170cdbf481SFabrice Gasnier #include <linux/regulator/of_regulator.h> 18*be5295f8SFabrice Gasnier #include <linux/pm_runtime.h> 190cdbf481SFabrice Gasnier 200cdbf481SFabrice Gasnier /* STM32 VREFBUF registers */ 210cdbf481SFabrice Gasnier #define STM32_VREFBUF_CSR 0x00 220cdbf481SFabrice Gasnier 230cdbf481SFabrice Gasnier /* STM32 VREFBUF CSR bitfields */ 240cdbf481SFabrice Gasnier #define STM32_VRS GENMASK(6, 4) 250cdbf481SFabrice Gasnier #define STM32_VRR BIT(3) 260cdbf481SFabrice Gasnier #define STM32_HIZ BIT(1) 270cdbf481SFabrice Gasnier #define STM32_ENVR BIT(0) 280cdbf481SFabrice Gasnier 29*be5295f8SFabrice Gasnier #define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10 30*be5295f8SFabrice Gasnier 310cdbf481SFabrice Gasnier struct stm32_vrefbuf { 320cdbf481SFabrice Gasnier void __iomem *base; 330cdbf481SFabrice Gasnier struct clk *clk; 34*be5295f8SFabrice Gasnier struct device *dev; 350cdbf481SFabrice Gasnier }; 360cdbf481SFabrice Gasnier 370cdbf481SFabrice Gasnier static const unsigned int stm32_vrefbuf_voltages[] = { 380cdbf481SFabrice Gasnier /* Matches resp. VRS = 000b, 001b, 010b, 011b */ 390cdbf481SFabrice Gasnier 2500000, 2048000, 1800000, 1500000, 400cdbf481SFabrice Gasnier }; 410cdbf481SFabrice Gasnier 420cdbf481SFabrice Gasnier static int stm32_vrefbuf_enable(struct regulator_dev *rdev) 430cdbf481SFabrice Gasnier { 440cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 45*be5295f8SFabrice Gasnier u32 val; 460cdbf481SFabrice Gasnier int ret; 470cdbf481SFabrice Gasnier 48*be5295f8SFabrice Gasnier ret = pm_runtime_get_sync(priv->dev); 49*be5295f8SFabrice Gasnier if (ret < 0) { 50*be5295f8SFabrice Gasnier pm_runtime_put_noidle(priv->dev); 51*be5295f8SFabrice Gasnier return ret; 52*be5295f8SFabrice Gasnier } 53*be5295f8SFabrice Gasnier 54*be5295f8SFabrice Gasnier val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 550cdbf481SFabrice Gasnier val = (val & ~STM32_HIZ) | STM32_ENVR; 560cdbf481SFabrice Gasnier writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 570cdbf481SFabrice Gasnier 580cdbf481SFabrice Gasnier /* 590cdbf481SFabrice Gasnier * Vrefbuf startup time depends on external capacitor: wait here for 600cdbf481SFabrice Gasnier * VRR to be set. That means output has reached expected value. 610cdbf481SFabrice Gasnier * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as 620cdbf481SFabrice Gasnier * arbitrary timeout. 630cdbf481SFabrice Gasnier */ 640cdbf481SFabrice Gasnier ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val, 65f63248faSFabrice Gasnier val & STM32_VRR, 650, 10000); 660cdbf481SFabrice Gasnier if (ret) { 670cdbf481SFabrice Gasnier dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n"); 680cdbf481SFabrice Gasnier val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 690cdbf481SFabrice Gasnier val = (val & ~STM32_ENVR) | STM32_HIZ; 700cdbf481SFabrice Gasnier writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 710cdbf481SFabrice Gasnier } 720cdbf481SFabrice Gasnier 73*be5295f8SFabrice Gasnier pm_runtime_mark_last_busy(priv->dev); 74*be5295f8SFabrice Gasnier pm_runtime_put_autosuspend(priv->dev); 75*be5295f8SFabrice Gasnier 760cdbf481SFabrice Gasnier return ret; 770cdbf481SFabrice Gasnier } 780cdbf481SFabrice Gasnier 790cdbf481SFabrice Gasnier static int stm32_vrefbuf_disable(struct regulator_dev *rdev) 800cdbf481SFabrice Gasnier { 810cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 82*be5295f8SFabrice Gasnier u32 val; 83*be5295f8SFabrice Gasnier int ret; 840cdbf481SFabrice Gasnier 85*be5295f8SFabrice Gasnier ret = pm_runtime_get_sync(priv->dev); 86*be5295f8SFabrice Gasnier if (ret < 0) { 87*be5295f8SFabrice Gasnier pm_runtime_put_noidle(priv->dev); 88*be5295f8SFabrice Gasnier return ret; 89*be5295f8SFabrice Gasnier } 90*be5295f8SFabrice Gasnier 91*be5295f8SFabrice Gasnier val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 920cdbf481SFabrice Gasnier val = (val & ~STM32_ENVR) | STM32_HIZ; 930cdbf481SFabrice Gasnier writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 940cdbf481SFabrice Gasnier 95*be5295f8SFabrice Gasnier pm_runtime_mark_last_busy(priv->dev); 96*be5295f8SFabrice Gasnier pm_runtime_put_autosuspend(priv->dev); 97*be5295f8SFabrice Gasnier 980cdbf481SFabrice Gasnier return 0; 990cdbf481SFabrice Gasnier } 1000cdbf481SFabrice Gasnier 1010cdbf481SFabrice Gasnier static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev) 1020cdbf481SFabrice Gasnier { 1030cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 104*be5295f8SFabrice Gasnier int ret; 1050cdbf481SFabrice Gasnier 106*be5295f8SFabrice Gasnier ret = pm_runtime_get_sync(priv->dev); 107*be5295f8SFabrice Gasnier if (ret < 0) { 108*be5295f8SFabrice Gasnier pm_runtime_put_noidle(priv->dev); 109*be5295f8SFabrice Gasnier return ret; 110*be5295f8SFabrice Gasnier } 111*be5295f8SFabrice Gasnier 112*be5295f8SFabrice Gasnier ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR; 113*be5295f8SFabrice Gasnier 114*be5295f8SFabrice Gasnier pm_runtime_mark_last_busy(priv->dev); 115*be5295f8SFabrice Gasnier pm_runtime_put_autosuspend(priv->dev); 116*be5295f8SFabrice Gasnier 117*be5295f8SFabrice Gasnier return ret; 1180cdbf481SFabrice Gasnier } 1190cdbf481SFabrice Gasnier 1200cdbf481SFabrice Gasnier static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev, 1210cdbf481SFabrice Gasnier unsigned sel) 1220cdbf481SFabrice Gasnier { 1230cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 124*be5295f8SFabrice Gasnier u32 val; 125*be5295f8SFabrice Gasnier int ret; 1260cdbf481SFabrice Gasnier 127*be5295f8SFabrice Gasnier ret = pm_runtime_get_sync(priv->dev); 128*be5295f8SFabrice Gasnier if (ret < 0) { 129*be5295f8SFabrice Gasnier pm_runtime_put_noidle(priv->dev); 130*be5295f8SFabrice Gasnier return ret; 131*be5295f8SFabrice Gasnier } 132*be5295f8SFabrice Gasnier 133*be5295f8SFabrice Gasnier val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 1340cdbf481SFabrice Gasnier val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel); 1350cdbf481SFabrice Gasnier writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 1360cdbf481SFabrice Gasnier 137*be5295f8SFabrice Gasnier pm_runtime_mark_last_busy(priv->dev); 138*be5295f8SFabrice Gasnier pm_runtime_put_autosuspend(priv->dev); 139*be5295f8SFabrice Gasnier 1400cdbf481SFabrice Gasnier return 0; 1410cdbf481SFabrice Gasnier } 1420cdbf481SFabrice Gasnier 1430cdbf481SFabrice Gasnier static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev) 1440cdbf481SFabrice Gasnier { 1450cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 146*be5295f8SFabrice Gasnier u32 val; 147*be5295f8SFabrice Gasnier int ret; 1480cdbf481SFabrice Gasnier 149*be5295f8SFabrice Gasnier ret = pm_runtime_get_sync(priv->dev); 150*be5295f8SFabrice Gasnier if (ret < 0) { 151*be5295f8SFabrice Gasnier pm_runtime_put_noidle(priv->dev); 152*be5295f8SFabrice Gasnier return ret; 153*be5295f8SFabrice Gasnier } 154*be5295f8SFabrice Gasnier 155*be5295f8SFabrice Gasnier val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 156*be5295f8SFabrice Gasnier ret = FIELD_GET(STM32_VRS, val); 157*be5295f8SFabrice Gasnier 158*be5295f8SFabrice Gasnier pm_runtime_mark_last_busy(priv->dev); 159*be5295f8SFabrice Gasnier pm_runtime_put_autosuspend(priv->dev); 160*be5295f8SFabrice Gasnier 161*be5295f8SFabrice Gasnier return ret; 1620cdbf481SFabrice Gasnier } 1630cdbf481SFabrice Gasnier 1640cdbf481SFabrice Gasnier static const struct regulator_ops stm32_vrefbuf_volt_ops = { 1650cdbf481SFabrice Gasnier .enable = stm32_vrefbuf_enable, 1660cdbf481SFabrice Gasnier .disable = stm32_vrefbuf_disable, 1670cdbf481SFabrice Gasnier .is_enabled = stm32_vrefbuf_is_enabled, 1680cdbf481SFabrice Gasnier .get_voltage_sel = stm32_vrefbuf_get_voltage_sel, 1690cdbf481SFabrice Gasnier .set_voltage_sel = stm32_vrefbuf_set_voltage_sel, 1700cdbf481SFabrice Gasnier .list_voltage = regulator_list_voltage_table, 1710cdbf481SFabrice Gasnier }; 1720cdbf481SFabrice Gasnier 1730cdbf481SFabrice Gasnier static const struct regulator_desc stm32_vrefbuf_regu = { 1740cdbf481SFabrice Gasnier .name = "vref", 1750cdbf481SFabrice Gasnier .supply_name = "vdda", 1760cdbf481SFabrice Gasnier .volt_table = stm32_vrefbuf_voltages, 1770cdbf481SFabrice Gasnier .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), 1780cdbf481SFabrice Gasnier .ops = &stm32_vrefbuf_volt_ops, 1790cdbf481SFabrice Gasnier .type = REGULATOR_VOLTAGE, 1800cdbf481SFabrice Gasnier .owner = THIS_MODULE, 1810cdbf481SFabrice Gasnier }; 1820cdbf481SFabrice Gasnier 1830cdbf481SFabrice Gasnier static int stm32_vrefbuf_probe(struct platform_device *pdev) 1840cdbf481SFabrice Gasnier { 1850cdbf481SFabrice Gasnier struct resource *res; 1860cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv; 1870cdbf481SFabrice Gasnier struct regulator_config config = { }; 1880cdbf481SFabrice Gasnier struct regulator_dev *rdev; 1890cdbf481SFabrice Gasnier int ret; 1900cdbf481SFabrice Gasnier 1910cdbf481SFabrice Gasnier priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 1920cdbf481SFabrice Gasnier if (!priv) 1930cdbf481SFabrice Gasnier return -ENOMEM; 194*be5295f8SFabrice Gasnier priv->dev = &pdev->dev; 1950cdbf481SFabrice Gasnier 1960cdbf481SFabrice Gasnier res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1970cdbf481SFabrice Gasnier priv->base = devm_ioremap_resource(&pdev->dev, res); 1980cdbf481SFabrice Gasnier if (IS_ERR(priv->base)) 1990cdbf481SFabrice Gasnier return PTR_ERR(priv->base); 2000cdbf481SFabrice Gasnier 2010cdbf481SFabrice Gasnier priv->clk = devm_clk_get(&pdev->dev, NULL); 2020cdbf481SFabrice Gasnier if (IS_ERR(priv->clk)) 2030cdbf481SFabrice Gasnier return PTR_ERR(priv->clk); 2040cdbf481SFabrice Gasnier 205*be5295f8SFabrice Gasnier pm_runtime_get_noresume(&pdev->dev); 206*be5295f8SFabrice Gasnier pm_runtime_set_active(&pdev->dev); 207*be5295f8SFabrice Gasnier pm_runtime_set_autosuspend_delay(&pdev->dev, 208*be5295f8SFabrice Gasnier STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS); 209*be5295f8SFabrice Gasnier pm_runtime_use_autosuspend(&pdev->dev); 210*be5295f8SFabrice Gasnier pm_runtime_enable(&pdev->dev); 211*be5295f8SFabrice Gasnier 2120cdbf481SFabrice Gasnier ret = clk_prepare_enable(priv->clk); 2130cdbf481SFabrice Gasnier if (ret) { 2140cdbf481SFabrice Gasnier dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret); 215*be5295f8SFabrice Gasnier goto err_pm_stop; 2160cdbf481SFabrice Gasnier } 2170cdbf481SFabrice Gasnier 2180cdbf481SFabrice Gasnier config.dev = &pdev->dev; 2190cdbf481SFabrice Gasnier config.driver_data = priv; 2200cdbf481SFabrice Gasnier config.of_node = pdev->dev.of_node; 2210cdbf481SFabrice Gasnier config.init_data = of_get_regulator_init_data(&pdev->dev, 2220cdbf481SFabrice Gasnier pdev->dev.of_node, 2230cdbf481SFabrice Gasnier &stm32_vrefbuf_regu); 2240cdbf481SFabrice Gasnier 2250cdbf481SFabrice Gasnier rdev = regulator_register(&stm32_vrefbuf_regu, &config); 2260cdbf481SFabrice Gasnier if (IS_ERR(rdev)) { 2270cdbf481SFabrice Gasnier ret = PTR_ERR(rdev); 2280cdbf481SFabrice Gasnier dev_err(&pdev->dev, "register failed with error %d\n", ret); 2290cdbf481SFabrice Gasnier goto err_clk_dis; 2300cdbf481SFabrice Gasnier } 2310cdbf481SFabrice Gasnier platform_set_drvdata(pdev, rdev); 2320cdbf481SFabrice Gasnier 233*be5295f8SFabrice Gasnier pm_runtime_mark_last_busy(&pdev->dev); 234*be5295f8SFabrice Gasnier pm_runtime_put_autosuspend(&pdev->dev); 235*be5295f8SFabrice Gasnier 2360cdbf481SFabrice Gasnier return 0; 2370cdbf481SFabrice Gasnier 2380cdbf481SFabrice Gasnier err_clk_dis: 2390cdbf481SFabrice Gasnier clk_disable_unprepare(priv->clk); 240*be5295f8SFabrice Gasnier err_pm_stop: 241*be5295f8SFabrice Gasnier pm_runtime_disable(&pdev->dev); 242*be5295f8SFabrice Gasnier pm_runtime_set_suspended(&pdev->dev); 243*be5295f8SFabrice Gasnier pm_runtime_put_noidle(&pdev->dev); 2440cdbf481SFabrice Gasnier 2450cdbf481SFabrice Gasnier return ret; 2460cdbf481SFabrice Gasnier } 2470cdbf481SFabrice Gasnier 2480cdbf481SFabrice Gasnier static int stm32_vrefbuf_remove(struct platform_device *pdev) 2490cdbf481SFabrice Gasnier { 2500cdbf481SFabrice Gasnier struct regulator_dev *rdev = platform_get_drvdata(pdev); 2510cdbf481SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 2520cdbf481SFabrice Gasnier 253*be5295f8SFabrice Gasnier pm_runtime_get_sync(&pdev->dev); 2540cdbf481SFabrice Gasnier regulator_unregister(rdev); 2550cdbf481SFabrice Gasnier clk_disable_unprepare(priv->clk); 256*be5295f8SFabrice Gasnier pm_runtime_disable(&pdev->dev); 257*be5295f8SFabrice Gasnier pm_runtime_set_suspended(&pdev->dev); 258*be5295f8SFabrice Gasnier pm_runtime_put_noidle(&pdev->dev); 259*be5295f8SFabrice Gasnier 260*be5295f8SFabrice Gasnier return 0; 261*be5295f8SFabrice Gasnier }; 262*be5295f8SFabrice Gasnier 263*be5295f8SFabrice Gasnier static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev) 264*be5295f8SFabrice Gasnier { 265*be5295f8SFabrice Gasnier struct regulator_dev *rdev = dev_get_drvdata(dev); 266*be5295f8SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 267*be5295f8SFabrice Gasnier 268*be5295f8SFabrice Gasnier clk_disable_unprepare(priv->clk); 2690cdbf481SFabrice Gasnier 2700cdbf481SFabrice Gasnier return 0; 271*be5295f8SFabrice Gasnier } 272*be5295f8SFabrice Gasnier 273*be5295f8SFabrice Gasnier static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev) 274*be5295f8SFabrice Gasnier { 275*be5295f8SFabrice Gasnier struct regulator_dev *rdev = dev_get_drvdata(dev); 276*be5295f8SFabrice Gasnier struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 277*be5295f8SFabrice Gasnier 278*be5295f8SFabrice Gasnier return clk_prepare_enable(priv->clk); 279*be5295f8SFabrice Gasnier } 280*be5295f8SFabrice Gasnier 281*be5295f8SFabrice Gasnier static const struct dev_pm_ops stm32_vrefbuf_pm_ops = { 282*be5295f8SFabrice Gasnier SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 283*be5295f8SFabrice Gasnier pm_runtime_force_resume) 284*be5295f8SFabrice Gasnier SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend, 285*be5295f8SFabrice Gasnier stm32_vrefbuf_runtime_resume, 286*be5295f8SFabrice Gasnier NULL) 2870cdbf481SFabrice Gasnier }; 2880cdbf481SFabrice Gasnier 2890cdbf481SFabrice Gasnier static const struct of_device_id stm32_vrefbuf_of_match[] = { 2900cdbf481SFabrice Gasnier { .compatible = "st,stm32-vrefbuf", }, 2910cdbf481SFabrice Gasnier {}, 2920cdbf481SFabrice Gasnier }; 2930cdbf481SFabrice Gasnier MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match); 2940cdbf481SFabrice Gasnier 2950cdbf481SFabrice Gasnier static struct platform_driver stm32_vrefbuf_driver = { 2960cdbf481SFabrice Gasnier .probe = stm32_vrefbuf_probe, 2970cdbf481SFabrice Gasnier .remove = stm32_vrefbuf_remove, 2980cdbf481SFabrice Gasnier .driver = { 2990cdbf481SFabrice Gasnier .name = "stm32-vrefbuf", 3000cdbf481SFabrice Gasnier .of_match_table = of_match_ptr(stm32_vrefbuf_of_match), 301*be5295f8SFabrice Gasnier .pm = &stm32_vrefbuf_pm_ops, 3020cdbf481SFabrice Gasnier }, 3030cdbf481SFabrice Gasnier }; 3040cdbf481SFabrice Gasnier module_platform_driver(stm32_vrefbuf_driver); 3050cdbf481SFabrice Gasnier 3060cdbf481SFabrice Gasnier MODULE_LICENSE("GPL v2"); 3070cdbf481SFabrice Gasnier MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); 3080cdbf481SFabrice Gasnier MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver"); 3090cdbf481SFabrice Gasnier MODULE_ALIAS("platform:stm32-vrefbuf"); 310