1 /* 2 * Copyright (c) 2016 MediaTek Inc. 3 * Author: Zhiyong Tao <zhiyong.tao@mediatek.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 */ 14 15 #include <linux/clk.h> 16 #include <linux/delay.h> 17 #include <linux/err.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/of.h> 21 #include <linux/of_device.h> 22 #include <linux/platform_device.h> 23 #include <linux/iopoll.h> 24 #include <linux/io.h> 25 #include <linux/iio/iio.h> 26 27 /* Register definitions */ 28 #define MT6577_AUXADC_CON0 0x00 29 #define MT6577_AUXADC_CON1 0x04 30 #define MT6577_AUXADC_CON2 0x10 31 #define MT6577_AUXADC_STA BIT(0) 32 33 #define MT6577_AUXADC_DAT0 0x14 34 #define MT6577_AUXADC_RDY0 BIT(12) 35 36 #define MT6577_AUXADC_MISC 0x94 37 #define MT6577_AUXADC_PDN_EN BIT(14) 38 39 #define MT6577_AUXADC_DAT_MASK 0xfff 40 #define MT6577_AUXADC_SLEEP_US 1000 41 #define MT6577_AUXADC_TIMEOUT_US 10000 42 #define MT6577_AUXADC_POWER_READY_MS 1 43 #define MT6577_AUXADC_SAMPLE_READY_US 25 44 45 struct mt6577_auxadc_device { 46 void __iomem *reg_base; 47 struct clk *adc_clk; 48 struct mutex lock; 49 }; 50 51 #define MT6577_AUXADC_CHANNEL(idx) { \ 52 .type = IIO_VOLTAGE, \ 53 .indexed = 1, \ 54 .channel = (idx), \ 55 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ 56 } 57 58 static const struct iio_chan_spec mt6577_auxadc_iio_channels[] = { 59 MT6577_AUXADC_CHANNEL(0), 60 MT6577_AUXADC_CHANNEL(1), 61 MT6577_AUXADC_CHANNEL(2), 62 MT6577_AUXADC_CHANNEL(3), 63 MT6577_AUXADC_CHANNEL(4), 64 MT6577_AUXADC_CHANNEL(5), 65 MT6577_AUXADC_CHANNEL(6), 66 MT6577_AUXADC_CHANNEL(7), 67 MT6577_AUXADC_CHANNEL(8), 68 MT6577_AUXADC_CHANNEL(9), 69 MT6577_AUXADC_CHANNEL(10), 70 MT6577_AUXADC_CHANNEL(11), 71 MT6577_AUXADC_CHANNEL(12), 72 MT6577_AUXADC_CHANNEL(13), 73 MT6577_AUXADC_CHANNEL(14), 74 MT6577_AUXADC_CHANNEL(15), 75 }; 76 77 static inline void mt6577_auxadc_mod_reg(void __iomem *reg, 78 u32 or_mask, u32 and_mask) 79 { 80 u32 val; 81 82 val = readl(reg); 83 val |= or_mask; 84 val &= ~and_mask; 85 writel(val, reg); 86 } 87 88 static int mt6577_auxadc_read(struct iio_dev *indio_dev, 89 struct iio_chan_spec const *chan) 90 { 91 u32 val; 92 void __iomem *reg_channel; 93 int ret; 94 struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev); 95 96 reg_channel = adc_dev->reg_base + MT6577_AUXADC_DAT0 + 97 chan->channel * 0x04; 98 99 mutex_lock(&adc_dev->lock); 100 101 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_CON1, 102 0, 1 << chan->channel); 103 104 /* read channel and make sure old ready bit == 0 */ 105 ret = readl_poll_timeout(reg_channel, val, 106 ((val & MT6577_AUXADC_RDY0) == 0), 107 MT6577_AUXADC_SLEEP_US, 108 MT6577_AUXADC_TIMEOUT_US); 109 if (ret < 0) { 110 dev_err(indio_dev->dev.parent, 111 "wait for channel[%d] ready bit clear time out\n", 112 chan->channel); 113 goto err_timeout; 114 } 115 116 /* set bit to trigger sample */ 117 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_CON1, 118 1 << chan->channel, 0); 119 120 /* we must delay here for hardware sample channel data */ 121 udelay(MT6577_AUXADC_SAMPLE_READY_US); 122 123 /* check MTK_AUXADC_CON2 if auxadc is idle */ 124 ret = readl_poll_timeout(adc_dev->reg_base + MT6577_AUXADC_CON2, val, 125 ((val & MT6577_AUXADC_STA) == 0), 126 MT6577_AUXADC_SLEEP_US, 127 MT6577_AUXADC_TIMEOUT_US); 128 if (ret < 0) { 129 dev_err(indio_dev->dev.parent, 130 "wait for auxadc idle time out\n"); 131 goto err_timeout; 132 } 133 134 /* read channel and make sure ready bit == 1 */ 135 ret = readl_poll_timeout(reg_channel, val, 136 ((val & MT6577_AUXADC_RDY0) != 0), 137 MT6577_AUXADC_SLEEP_US, 138 MT6577_AUXADC_TIMEOUT_US); 139 if (ret < 0) { 140 dev_err(indio_dev->dev.parent, 141 "wait for channel[%d] data ready time out\n", 142 chan->channel); 143 goto err_timeout; 144 } 145 146 /* read data */ 147 val = readl(reg_channel) & MT6577_AUXADC_DAT_MASK; 148 149 mutex_unlock(&adc_dev->lock); 150 151 return val; 152 153 err_timeout: 154 155 mutex_unlock(&adc_dev->lock); 156 157 return -ETIMEDOUT; 158 } 159 160 static int mt6577_auxadc_read_raw(struct iio_dev *indio_dev, 161 struct iio_chan_spec const *chan, 162 int *val, 163 int *val2, 164 long info) 165 { 166 switch (info) { 167 case IIO_CHAN_INFO_PROCESSED: 168 *val = mt6577_auxadc_read(indio_dev, chan); 169 if (*val < 0) { 170 dev_err(indio_dev->dev.parent, 171 "failed to sample data on channel[%d]\n", 172 chan->channel); 173 return *val; 174 } 175 return IIO_VAL_INT; 176 177 default: 178 return -EINVAL; 179 } 180 } 181 182 static const struct iio_info mt6577_auxadc_info = { 183 .driver_module = THIS_MODULE, 184 .read_raw = &mt6577_auxadc_read_raw, 185 }; 186 187 static int mt6577_auxadc_probe(struct platform_device *pdev) 188 { 189 struct mt6577_auxadc_device *adc_dev; 190 unsigned long adc_clk_rate; 191 struct resource *res; 192 struct iio_dev *indio_dev; 193 int ret; 194 195 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev)); 196 if (!indio_dev) 197 return -ENOMEM; 198 199 adc_dev = iio_priv(indio_dev); 200 indio_dev->dev.parent = &pdev->dev; 201 indio_dev->name = dev_name(&pdev->dev); 202 indio_dev->info = &mt6577_auxadc_info; 203 indio_dev->modes = INDIO_DIRECT_MODE; 204 indio_dev->channels = mt6577_auxadc_iio_channels; 205 indio_dev->num_channels = ARRAY_SIZE(mt6577_auxadc_iio_channels); 206 207 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 208 adc_dev->reg_base = devm_ioremap_resource(&pdev->dev, res); 209 if (IS_ERR(adc_dev->reg_base)) { 210 dev_err(&pdev->dev, "failed to get auxadc base address\n"); 211 return PTR_ERR(adc_dev->reg_base); 212 } 213 214 adc_dev->adc_clk = devm_clk_get(&pdev->dev, "main"); 215 if (IS_ERR(adc_dev->adc_clk)) { 216 dev_err(&pdev->dev, "failed to get auxadc clock\n"); 217 return PTR_ERR(adc_dev->adc_clk); 218 } 219 220 ret = clk_prepare_enable(adc_dev->adc_clk); 221 if (ret) { 222 dev_err(&pdev->dev, "failed to enable auxadc clock\n"); 223 return ret; 224 } 225 226 adc_clk_rate = clk_get_rate(adc_dev->adc_clk); 227 if (!adc_clk_rate) { 228 ret = -EINVAL; 229 dev_err(&pdev->dev, "null clock rate\n"); 230 goto err_disable_clk; 231 } 232 233 mutex_init(&adc_dev->lock); 234 235 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC, 236 MT6577_AUXADC_PDN_EN, 0); 237 mdelay(MT6577_AUXADC_POWER_READY_MS); 238 239 platform_set_drvdata(pdev, indio_dev); 240 241 ret = iio_device_register(indio_dev); 242 if (ret < 0) { 243 dev_err(&pdev->dev, "failed to register iio device\n"); 244 goto err_power_off; 245 } 246 247 return 0; 248 249 err_power_off: 250 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC, 251 0, MT6577_AUXADC_PDN_EN); 252 err_disable_clk: 253 clk_disable_unprepare(adc_dev->adc_clk); 254 return ret; 255 } 256 257 static int mt6577_auxadc_remove(struct platform_device *pdev) 258 { 259 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 260 struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev); 261 262 iio_device_unregister(indio_dev); 263 264 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC, 265 0, MT6577_AUXADC_PDN_EN); 266 267 clk_disable_unprepare(adc_dev->adc_clk); 268 269 return 0; 270 } 271 272 static const struct of_device_id mt6577_auxadc_of_match[] = { 273 { .compatible = "mediatek,mt2701-auxadc", }, 274 { .compatible = "mediatek,mt8173-auxadc", }, 275 { } 276 }; 277 MODULE_DEVICE_TABLE(of, mt6577_auxadc_of_match); 278 279 static struct platform_driver mt6577_auxadc_driver = { 280 .driver = { 281 .name = "mt6577-auxadc", 282 .of_match_table = mt6577_auxadc_of_match, 283 }, 284 .probe = mt6577_auxadc_probe, 285 .remove = mt6577_auxadc_remove, 286 }; 287 module_platform_driver(mt6577_auxadc_driver); 288 289 MODULE_AUTHOR("Zhiyong Tao <zhiyong.tao@mediatek.com>"); 290 MODULE_DESCRIPTION("MTK AUXADC Device Driver"); 291 MODULE_LICENSE("GPL v2"); 292