Fabrice Gasnier | 0cdbf48 | 2017-08-30 17:55:28 +0200 | [diff] [blame] | 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 | |
| 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 | struct stm32_vrefbuf { |
| 29 | void __iomem *base; |
| 30 | struct clk *clk; |
| 31 | }; |
| 32 | |
| 33 | static const unsigned int stm32_vrefbuf_voltages[] = { |
| 34 | /* Matches resp. VRS = 000b, 001b, 010b, 011b */ |
| 35 | 2500000, 2048000, 1800000, 1500000, |
| 36 | }; |
| 37 | |
| 38 | static int stm32_vrefbuf_enable(struct regulator_dev *rdev) |
| 39 | { |
| 40 | struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
| 41 | u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
| 42 | int ret; |
| 43 | |
| 44 | val = (val & ~STM32_HIZ) | STM32_ENVR; |
| 45 | writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
| 46 | |
| 47 | /* |
| 48 | * Vrefbuf startup time depends on external capacitor: wait here for |
| 49 | * VRR to be set. That means output has reached expected value. |
| 50 | * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as |
| 51 | * arbitrary timeout. |
| 52 | */ |
| 53 | ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val, |
Fabrice Gasnier | f63248f | 2018-02-08 14:43:05 +0100 | [diff] [blame] | 54 | val & STM32_VRR, 650, 10000); |
Fabrice Gasnier | 0cdbf48 | 2017-08-30 17:55:28 +0200 | [diff] [blame] | 55 | if (ret) { |
| 56 | dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n"); |
| 57 | val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
| 58 | val = (val & ~STM32_ENVR) | STM32_HIZ; |
| 59 | writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
| 60 | } |
| 61 | |
| 62 | return ret; |
| 63 | } |
| 64 | |
| 65 | static int stm32_vrefbuf_disable(struct regulator_dev *rdev) |
| 66 | { |
| 67 | struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
| 68 | u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
| 69 | |
| 70 | val = (val & ~STM32_ENVR) | STM32_HIZ; |
| 71 | writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
| 72 | |
| 73 | return 0; |
| 74 | } |
| 75 | |
| 76 | static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev) |
| 77 | { |
| 78 | struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
| 79 | |
| 80 | return readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR; |
| 81 | } |
| 82 | |
| 83 | static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev, |
| 84 | unsigned sel) |
| 85 | { |
| 86 | struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
| 87 | u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
| 88 | |
| 89 | val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel); |
| 90 | writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | |
| 95 | static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev) |
| 96 | { |
| 97 | struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
| 98 | u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); |
| 99 | |
| 100 | return FIELD_GET(STM32_VRS, val); |
| 101 | } |
| 102 | |
| 103 | static const struct regulator_ops stm32_vrefbuf_volt_ops = { |
| 104 | .enable = stm32_vrefbuf_enable, |
| 105 | .disable = stm32_vrefbuf_disable, |
| 106 | .is_enabled = stm32_vrefbuf_is_enabled, |
| 107 | .get_voltage_sel = stm32_vrefbuf_get_voltage_sel, |
| 108 | .set_voltage_sel = stm32_vrefbuf_set_voltage_sel, |
| 109 | .list_voltage = regulator_list_voltage_table, |
| 110 | }; |
| 111 | |
| 112 | static const struct regulator_desc stm32_vrefbuf_regu = { |
| 113 | .name = "vref", |
| 114 | .supply_name = "vdda", |
| 115 | .volt_table = stm32_vrefbuf_voltages, |
| 116 | .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), |
| 117 | .ops = &stm32_vrefbuf_volt_ops, |
| 118 | .type = REGULATOR_VOLTAGE, |
| 119 | .owner = THIS_MODULE, |
| 120 | }; |
| 121 | |
| 122 | static int stm32_vrefbuf_probe(struct platform_device *pdev) |
| 123 | { |
| 124 | struct resource *res; |
| 125 | struct stm32_vrefbuf *priv; |
| 126 | struct regulator_config config = { }; |
| 127 | struct regulator_dev *rdev; |
| 128 | int ret; |
| 129 | |
| 130 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
| 131 | if (!priv) |
| 132 | return -ENOMEM; |
| 133 | |
| 134 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 135 | priv->base = devm_ioremap_resource(&pdev->dev, res); |
| 136 | if (IS_ERR(priv->base)) |
| 137 | return PTR_ERR(priv->base); |
| 138 | |
| 139 | priv->clk = devm_clk_get(&pdev->dev, NULL); |
| 140 | if (IS_ERR(priv->clk)) |
| 141 | return PTR_ERR(priv->clk); |
| 142 | |
| 143 | ret = clk_prepare_enable(priv->clk); |
| 144 | if (ret) { |
| 145 | dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret); |
| 146 | return ret; |
| 147 | } |
| 148 | |
| 149 | config.dev = &pdev->dev; |
| 150 | config.driver_data = priv; |
| 151 | config.of_node = pdev->dev.of_node; |
| 152 | config.init_data = of_get_regulator_init_data(&pdev->dev, |
| 153 | pdev->dev.of_node, |
| 154 | &stm32_vrefbuf_regu); |
| 155 | |
| 156 | rdev = regulator_register(&stm32_vrefbuf_regu, &config); |
| 157 | if (IS_ERR(rdev)) { |
| 158 | ret = PTR_ERR(rdev); |
| 159 | dev_err(&pdev->dev, "register failed with error %d\n", ret); |
| 160 | goto err_clk_dis; |
| 161 | } |
| 162 | platform_set_drvdata(pdev, rdev); |
| 163 | |
| 164 | return 0; |
| 165 | |
| 166 | err_clk_dis: |
| 167 | clk_disable_unprepare(priv->clk); |
| 168 | |
| 169 | return ret; |
| 170 | } |
| 171 | |
| 172 | static int stm32_vrefbuf_remove(struct platform_device *pdev) |
| 173 | { |
| 174 | struct regulator_dev *rdev = platform_get_drvdata(pdev); |
| 175 | struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev); |
| 176 | |
| 177 | regulator_unregister(rdev); |
| 178 | clk_disable_unprepare(priv->clk); |
| 179 | |
| 180 | return 0; |
| 181 | }; |
| 182 | |
| 183 | static const struct of_device_id stm32_vrefbuf_of_match[] = { |
| 184 | { .compatible = "st,stm32-vrefbuf", }, |
| 185 | {}, |
| 186 | }; |
| 187 | MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match); |
| 188 | |
| 189 | static struct platform_driver stm32_vrefbuf_driver = { |
| 190 | .probe = stm32_vrefbuf_probe, |
| 191 | .remove = stm32_vrefbuf_remove, |
| 192 | .driver = { |
| 193 | .name = "stm32-vrefbuf", |
| 194 | .of_match_table = of_match_ptr(stm32_vrefbuf_of_match), |
| 195 | }, |
| 196 | }; |
| 197 | module_platform_driver(stm32_vrefbuf_driver); |
| 198 | |
| 199 | MODULE_LICENSE("GPL v2"); |
| 200 | MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); |
| 201 | MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver"); |
| 202 | MODULE_ALIAS("platform:stm32-vrefbuf"); |