1 /* 2 * Copyright (C) STMicroelectronics 2017 3 * 4 * Author: Fabrice Gasnier <fabrice.gasnier@st.com> 5 * 6 * License terms: GNU General Public License (GPL), version 2 7 */ 8 9 #include <linux/bitfield.h> 10 #include <linux/clk.h> 11 #include <linux/io.h> 12 #include <linux/iopoll.h> 13 #include <linux/module.h> 14 #include <linux/of_device.h> 15 #include <linux/platform_device.h> 16 #include <linux/regulator/driver.h> 17 #include <linux/regulator/of_regulator.h> 18 #include <linux/pm_runtime.h> 19 20 /* STM32 VREFBUF registers */ 21 #define STM32_VREFBUF_CSR 0x00 22 23 /* STM32 VREFBUF CSR bitfields */ 24 #define STM32_VRS GENMASK(6, 4) 25 #define STM32_VRR BIT(3) 26 #define STM32_HIZ BIT(1) 27 #define STM32_ENVR BIT(0) 28 29 #define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10 30 31 struct stm32_vrefbuf { 32 void __iomem *base; 33 struct clk *clk; 34 struct device *dev; 35 }; 36 37 static const unsigned int stm32_vrefbuf_voltages[] = { 38 /* Matches resp. VRS = 000b, 001b, 010b, 011b */ 39 2500000, 2048000, 1800000, 1500000, 40 }; 41 42 static int stm32_vrefbuf_enable(struct regulator_dev *rdev) 43 { 44 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 45 u32 val; 46 int ret; 47 48 ret = pm_runtime_get_sync(priv->dev); 49 if (ret < 0) { 50 pm_runtime_put_noidle(priv->dev); 51 return ret; 52 } 53 54 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 55 val = (val & ~STM32_HIZ) | STM32_ENVR; 56 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 57 58 /* 59 * Vrefbuf startup time depends on external capacitor: wait here for 60 * VRR to be set. That means output has reached expected value. 61 * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as 62 * arbitrary timeout. 63 */ 64 ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val, 65 val & STM32_VRR, 650, 10000); 66 if (ret) { 67 dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n"); 68 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 69 val = (val & ~STM32_ENVR) | STM32_HIZ; 70 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 71 } 72 73 pm_runtime_mark_last_busy(priv->dev); 74 pm_runtime_put_autosuspend(priv->dev); 75 76 return ret; 77 } 78 79 static int stm32_vrefbuf_disable(struct regulator_dev *rdev) 80 { 81 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 82 u32 val; 83 int ret; 84 85 ret = pm_runtime_get_sync(priv->dev); 86 if (ret < 0) { 87 pm_runtime_put_noidle(priv->dev); 88 return ret; 89 } 90 91 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 92 val = (val & ~STM32_ENVR) | STM32_HIZ; 93 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 94 95 pm_runtime_mark_last_busy(priv->dev); 96 pm_runtime_put_autosuspend(priv->dev); 97 98 return 0; 99 } 100 101 static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev) 102 { 103 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 104 int ret; 105 106 ret = pm_runtime_get_sync(priv->dev); 107 if (ret < 0) { 108 pm_runtime_put_noidle(priv->dev); 109 return ret; 110 } 111 112 ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR; 113 114 pm_runtime_mark_last_busy(priv->dev); 115 pm_runtime_put_autosuspend(priv->dev); 116 117 return ret; 118 } 119 120 static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev, 121 unsigned sel) 122 { 123 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 124 u32 val; 125 int ret; 126 127 ret = pm_runtime_get_sync(priv->dev); 128 if (ret < 0) { 129 pm_runtime_put_noidle(priv->dev); 130 return ret; 131 } 132 133 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 134 val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel); 135 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); 136 137 pm_runtime_mark_last_busy(priv->dev); 138 pm_runtime_put_autosuspend(priv->dev); 139 140 return 0; 141 } 142 143 static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev) 144 { 145 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 146 u32 val; 147 int ret; 148 149 ret = pm_runtime_get_sync(priv->dev); 150 if (ret < 0) { 151 pm_runtime_put_noidle(priv->dev); 152 return ret; 153 } 154 155 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); 156 ret = FIELD_GET(STM32_VRS, val); 157 158 pm_runtime_mark_last_busy(priv->dev); 159 pm_runtime_put_autosuspend(priv->dev); 160 161 return ret; 162 } 163 164 static const struct regulator_ops stm32_vrefbuf_volt_ops = { 165 .enable = stm32_vrefbuf_enable, 166 .disable = stm32_vrefbuf_disable, 167 .is_enabled = stm32_vrefbuf_is_enabled, 168 .get_voltage_sel = stm32_vrefbuf_get_voltage_sel, 169 .set_voltage_sel = stm32_vrefbuf_set_voltage_sel, 170 .list_voltage = regulator_list_voltage_table, 171 }; 172 173 static const struct regulator_desc stm32_vrefbuf_regu = { 174 .name = "vref", 175 .supply_name = "vdda", 176 .volt_table = stm32_vrefbuf_voltages, 177 .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), 178 .ops = &stm32_vrefbuf_volt_ops, 179 .type = REGULATOR_VOLTAGE, 180 .owner = THIS_MODULE, 181 }; 182 183 static int stm32_vrefbuf_probe(struct platform_device *pdev) 184 { 185 struct resource *res; 186 struct stm32_vrefbuf *priv; 187 struct regulator_config config = { }; 188 struct regulator_dev *rdev; 189 int ret; 190 191 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 192 if (!priv) 193 return -ENOMEM; 194 priv->dev = &pdev->dev; 195 196 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 197 priv->base = devm_ioremap_resource(&pdev->dev, res); 198 if (IS_ERR(priv->base)) 199 return PTR_ERR(priv->base); 200 201 priv->clk = devm_clk_get(&pdev->dev, NULL); 202 if (IS_ERR(priv->clk)) 203 return PTR_ERR(priv->clk); 204 205 pm_runtime_get_noresume(&pdev->dev); 206 pm_runtime_set_active(&pdev->dev); 207 pm_runtime_set_autosuspend_delay(&pdev->dev, 208 STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS); 209 pm_runtime_use_autosuspend(&pdev->dev); 210 pm_runtime_enable(&pdev->dev); 211 212 ret = clk_prepare_enable(priv->clk); 213 if (ret) { 214 dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret); 215 goto err_pm_stop; 216 } 217 218 config.dev = &pdev->dev; 219 config.driver_data = priv; 220 config.of_node = pdev->dev.of_node; 221 config.init_data = of_get_regulator_init_data(&pdev->dev, 222 pdev->dev.of_node, 223 &stm32_vrefbuf_regu); 224 225 rdev = regulator_register(&stm32_vrefbuf_regu, &config); 226 if (IS_ERR(rdev)) { 227 ret = PTR_ERR(rdev); 228 dev_err(&pdev->dev, "register failed with error %d\n", ret); 229 goto err_clk_dis; 230 } 231 platform_set_drvdata(pdev, rdev); 232 233 pm_runtime_mark_last_busy(&pdev->dev); 234 pm_runtime_put_autosuspend(&pdev->dev); 235 236 return 0; 237 238 err_clk_dis: 239 clk_disable_unprepare(priv->clk); 240 err_pm_stop: 241 pm_runtime_disable(&pdev->dev); 242 pm_runtime_set_suspended(&pdev->dev); 243 pm_runtime_put_noidle(&pdev->dev); 244 245 return ret; 246 } 247 248 static int stm32_vrefbuf_remove(struct platform_device *pdev) 249 { 250 struct regulator_dev *rdev = platform_get_drvdata(pdev); 251 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 252 253 pm_runtime_get_sync(&pdev->dev); 254 regulator_unregister(rdev); 255 clk_disable_unprepare(priv->clk); 256 pm_runtime_disable(&pdev->dev); 257 pm_runtime_set_suspended(&pdev->dev); 258 pm_runtime_put_noidle(&pdev->dev); 259 260 return 0; 261 }; 262 263 static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev) 264 { 265 struct regulator_dev *rdev = dev_get_drvdata(dev); 266 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 267 268 clk_disable_unprepare(priv->clk); 269 270 return 0; 271 } 272 273 static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev) 274 { 275 struct regulator_dev *rdev = dev_get_drvdata(dev); 276 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); 277 278 return clk_prepare_enable(priv->clk); 279 } 280 281 static const struct dev_pm_ops stm32_vrefbuf_pm_ops = { 282 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 283 pm_runtime_force_resume) 284 SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend, 285 stm32_vrefbuf_runtime_resume, 286 NULL) 287 }; 288 289 static const struct of_device_id stm32_vrefbuf_of_match[] = { 290 { .compatible = "st,stm32-vrefbuf", }, 291 {}, 292 }; 293 MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match); 294 295 static struct platform_driver stm32_vrefbuf_driver = { 296 .probe = stm32_vrefbuf_probe, 297 .remove = stm32_vrefbuf_remove, 298 .driver = { 299 .name = "stm32-vrefbuf", 300 .of_match_table = of_match_ptr(stm32_vrefbuf_of_match), 301 .pm = &stm32_vrefbuf_pm_ops, 302 }, 303 }; 304 module_platform_driver(stm32_vrefbuf_driver); 305 306 MODULE_LICENSE("GPL v2"); 307 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); 308 MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver"); 309 MODULE_ALIAS("platform:stm32-vrefbuf"); 310