1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) STMicroelectronics 2017 4 * 5 * Author: Fabrice Gasnier <fabrice.gasnier@st.com> 6 */ 7 8 #include <linux/bitfield.h> 9 #include <linux/clk.h> 10 #include <linux/io.h> 11 #include <linux/iopoll.h> 12 #include <linux/module.h> 13 #include <linux/of_device.h> 14 #include <linux/platform_device.h> 15 #include <linux/regulator/driver.h> 16 #include <linux/regulator/of_regulator.h> 17 #include <linux/pm_runtime.h> 18 19 /* STM32 VREFBUF registers */ 20 #define STM32_VREFBUF_CSR 0x00 21 22 /* STM32 VREFBUF CSR bitfields */ 23 #define STM32_VRS GENMASK(6, 4) 24 #define STM32_VRR BIT(3) 25 #define STM32_HIZ BIT(1) 26 #define STM32_ENVR BIT(0) 27 28 #define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10 29 30 struct stm32_vrefbuf { 31 void __iomem *base; 32 struct clk *clk; 33 struct device *dev; 34 }; 35 36 static const unsigned int stm32_vrefbuf_voltages[] = { 37 /* Matches resp. VRS = 000b, 001b, 010b, 011b */ 38 2500000, 2048000, 1800000, 1500000, 39 }; 40 41 static int stm32_vrefbuf_enable(struct regulator_dev *rdev) 42 { 43 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 44 u32 val; 45 int ret; 46 47 ret = pm_runtime_get_sync(priv->dev); 48 if (ret < 0) { 49 pm_runtime_put_noidle(priv->dev); 50 return ret; 51 } 52 53 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 54 val = (val & ~STM32_HIZ) | STM32_ENVR; 55 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 56 57 /* 58 * Vrefbuf startup time depends on external capacitor: wait here for 59 * VRR to be set. That means output has reached expected value. 60 * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as 61 * arbitrary timeout. 62 */ 63 ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val, 64 val & STM32_VRR, 650, 10000); 65 if (ret) { 66 dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n"); 67 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 68 val = (val & ~STM32_ENVR) | STM32_HIZ; 69 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 70 } 71 72 pm_runtime_mark_last_busy(priv->dev); 73 pm_runtime_put_autosuspend(priv->dev); 74 75 return ret; 76 } 77 78 static int stm32_vrefbuf_disable(struct regulator_dev *rdev) 79 { 80 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 81 u32 val; 82 int ret; 83 84 ret = pm_runtime_get_sync(priv->dev); 85 if (ret < 0) { 86 pm_runtime_put_noidle(priv->dev); 87 return ret; 88 } 89 90 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 91 val &= ~STM32_ENVR; 92 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 93 94 pm_runtime_mark_last_busy(priv->dev); 95 pm_runtime_put_autosuspend(priv->dev); 96 97 return 0; 98 } 99 100 static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev) 101 { 102 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 103 int ret; 104 105 ret = pm_runtime_get_sync(priv->dev); 106 if (ret < 0) { 107 pm_runtime_put_noidle(priv->dev); 108 return ret; 109 } 110 111 ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR; 112 113 pm_runtime_mark_last_busy(priv->dev); 114 pm_runtime_put_autosuspend(priv->dev); 115 116 return ret; 117 } 118 119 static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev, 120 unsigned sel) 121 { 122 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 123 u32 val; 124 int ret; 125 126 ret = pm_runtime_get_sync(priv->dev); 127 if (ret < 0) { 128 pm_runtime_put_noidle(priv->dev); 129 return ret; 130 } 131 132 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 133 val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel); 134 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 135 136 pm_runtime_mark_last_busy(priv->dev); 137 pm_runtime_put_autosuspend(priv->dev); 138 139 return 0; 140 } 141 142 static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev) 143 { 144 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 145 u32 val; 146 int ret; 147 148 ret = pm_runtime_get_sync(priv->dev); 149 if (ret < 0) { 150 pm_runtime_put_noidle(priv->dev); 151 return ret; 152 } 153 154 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 155 ret = FIELD_GET(STM32_VRS, val); 156 157 pm_runtime_mark_last_busy(priv->dev); 158 pm_runtime_put_autosuspend(priv->dev); 159 160 return ret; 161 } 162 163 static const struct regulator_ops stm32_vrefbuf_volt_ops = { 164 .enable = stm32_vrefbuf_enable, 165 .disable = stm32_vrefbuf_disable, 166 .is_enabled = stm32_vrefbuf_is_enabled, 167 .get_voltage_sel = stm32_vrefbuf_get_voltage_sel, 168 .set_voltage_sel = stm32_vrefbuf_set_voltage_sel, 169 .list_voltage = regulator_list_voltage_table, 170 }; 171 172 static const struct regulator_desc stm32_vrefbuf_regu = { 173 .name = "vref", 174 .supply_name = "vdda", 175 .volt_table = stm32_vrefbuf_voltages, 176 .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), 177 .ops = &stm32_vrefbuf_volt_ops, 178 .off_on_delay = 1000, 179 .type = REGULATOR_VOLTAGE, 180 .owner = THIS_MODULE, 181 }; 182 183 static int stm32_vrefbuf_probe(struct platform_device *pdev) 184 { 185 struct stm32_vrefbuf *priv; 186 struct regulator_config config = { }; 187 struct regulator_dev *rdev; 188 int ret; 189 190 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 191 if (!priv) 192 return -ENOMEM; 193 priv->dev = &pdev->dev; 194 195 priv->base = devm_platform_ioremap_resource(pdev, 0); 196 if (IS_ERR(priv->base)) 197 return PTR_ERR(priv->base); 198 199 priv->clk = devm_clk_get(&pdev->dev, NULL); 200 if (IS_ERR(priv->clk)) 201 return PTR_ERR(priv->clk); 202 203 pm_runtime_get_noresume(&pdev->dev); 204 pm_runtime_set_active(&pdev->dev); 205 pm_runtime_set_autosuspend_delay(&pdev->dev, 206 STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS); 207 pm_runtime_use_autosuspend(&pdev->dev); 208 pm_runtime_enable(&pdev->dev); 209 210 ret = clk_prepare_enable(priv->clk); 211 if (ret) { 212 dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret); 213 goto err_pm_stop; 214 } 215 216 config.dev = &pdev->dev; 217 config.driver_data = priv; 218 config.of_node = pdev->dev.of_node; 219 config.init_data = of_get_regulator_init_data(&pdev->dev, 220 pdev->dev.of_node, 221 &stm32_vrefbuf_regu); 222 223 rdev = regulator_register(&stm32_vrefbuf_regu, &config); 224 if (IS_ERR(rdev)) { 225 ret = PTR_ERR(rdev); 226 dev_err(&pdev->dev, "register failed with error %d\n", ret); 227 goto err_clk_dis; 228 } 229 platform_set_drvdata(pdev, rdev); 230 231 pm_runtime_mark_last_busy(&pdev->dev); 232 pm_runtime_put_autosuspend(&pdev->dev); 233 234 return 0; 235 236 err_clk_dis: 237 clk_disable_unprepare(priv->clk); 238 err_pm_stop: 239 pm_runtime_disable(&pdev->dev); 240 pm_runtime_set_suspended(&pdev->dev); 241 pm_runtime_put_noidle(&pdev->dev); 242 243 return ret; 244 } 245 246 static int stm32_vrefbuf_remove(struct platform_device *pdev) 247 { 248 struct regulator_dev *rdev = platform_get_drvdata(pdev); 249 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 250 251 pm_runtime_get_sync(&pdev->dev); 252 regulator_unregister(rdev); 253 clk_disable_unprepare(priv->clk); 254 pm_runtime_disable(&pdev->dev); 255 pm_runtime_set_suspended(&pdev->dev); 256 pm_runtime_put_noidle(&pdev->dev); 257 258 return 0; 259 }; 260 261 static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev) 262 { 263 struct regulator_dev *rdev = dev_get_drvdata(dev); 264 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 265 266 clk_disable_unprepare(priv->clk); 267 268 return 0; 269 } 270 271 static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev) 272 { 273 struct regulator_dev *rdev = dev_get_drvdata(dev); 274 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 275 276 return clk_prepare_enable(priv->clk); 277 } 278 279 static const struct dev_pm_ops stm32_vrefbuf_pm_ops = { 280 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 281 pm_runtime_force_resume) 282 SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend, 283 stm32_vrefbuf_runtime_resume, 284 NULL) 285 }; 286 287 static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = { 288 { .compatible = "st,stm32-vrefbuf", }, 289 {}, 290 }; 291 MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match); 292 293 static struct platform_driver stm32_vrefbuf_driver = { 294 .probe = stm32_vrefbuf_probe, 295 .remove = stm32_vrefbuf_remove, 296 .driver = { 297 .name = "stm32-vrefbuf", 298 .of_match_table = of_match_ptr(stm32_vrefbuf_of_match), 299 .pm = &stm32_vrefbuf_pm_ops, 300 }, 301 }; 302 module_platform_driver(stm32_vrefbuf_driver); 303 304 MODULE_LICENSE("GPL v2"); 305 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); 306 MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver"); 307 MODULE_ALIAS("platform:stm32-vrefbuf"); 308