1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * lpc32xx_adc.c - Support for ADC in LPC32XX 4 * 5 * 3-channel, 10-bit ADC 6 * 7 * Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.de> 8 */ 9 10 #include <linux/clk.h> 11 #include <linux/completion.h> 12 #include <linux/err.h> 13 #include <linux/iio/iio.h> 14 #include <linux/interrupt.h> 15 #include <linux/io.h> 16 #include <linux/module.h> 17 #include <linux/platform_device.h> 18 #include <linux/regulator/consumer.h> 19 20 /* 21 * LPC32XX registers definitions 22 */ 23 #define LPC32XXAD_SELECT(x) ((x) + 0x04) 24 #define LPC32XXAD_CTRL(x) ((x) + 0x08) 25 #define LPC32XXAD_VALUE(x) ((x) + 0x48) 26 27 /* Bit definitions for LPC32XXAD_SELECT: */ 28 /* constant, always write this value! */ 29 #define LPC32XXAD_REFm 0x00000200 30 /* constant, always write this value! */ 31 #define LPC32XXAD_REFp 0x00000080 32 /* multiple of this is the channel number: 0, 1, 2 */ 33 #define LPC32XXAD_IN 0x00000010 34 /* constant, always write this value! */ 35 #define LPC32XXAD_INTERNAL 0x00000004 36 37 /* Bit definitions for LPC32XXAD_CTRL: */ 38 #define LPC32XXAD_STROBE 0x00000002 39 #define LPC32XXAD_PDN_CTRL 0x00000004 40 41 /* Bit definitions for LPC32XXAD_VALUE: */ 42 #define LPC32XXAD_VALUE_MASK 0x000003FF 43 44 #define LPC32XXAD_NAME "lpc32xx-adc" 45 46 struct lpc32xx_adc_state { 47 void __iomem *adc_base; 48 struct clk *clk; 49 struct completion completion; 50 struct regulator *vref; 51 52 u32 value; 53 }; 54 55 static int lpc32xx_read_raw(struct iio_dev *indio_dev, 56 struct iio_chan_spec const *chan, 57 int *val, 58 int *val2, 59 long mask) 60 { 61 struct lpc32xx_adc_state *st = iio_priv(indio_dev); 62 int ret; 63 64 switch (mask) { 65 case IIO_CHAN_INFO_RAW: 66 mutex_lock(&indio_dev->mlock); 67 ret = clk_prepare_enable(st->clk); 68 if (ret) { 69 mutex_unlock(&indio_dev->mlock); 70 return ret; 71 } 72 /* Measurement setup */ 73 __raw_writel(LPC32XXAD_INTERNAL | (chan->address) | 74 LPC32XXAD_REFp | LPC32XXAD_REFm, 75 LPC32XXAD_SELECT(st->adc_base)); 76 /* Trigger conversion */ 77 __raw_writel(LPC32XXAD_PDN_CTRL | LPC32XXAD_STROBE, 78 LPC32XXAD_CTRL(st->adc_base)); 79 wait_for_completion(&st->completion); /* set by ISR */ 80 clk_disable_unprepare(st->clk); 81 *val = st->value; 82 mutex_unlock(&indio_dev->mlock); 83 84 return IIO_VAL_INT; 85 86 case IIO_CHAN_INFO_SCALE: 87 *val = regulator_get_voltage(st->vref) / 1000; 88 *val2 = 10; 89 90 return IIO_VAL_FRACTIONAL_LOG2; 91 default: 92 return -EINVAL; 93 } 94 } 95 96 static const struct iio_info lpc32xx_adc_iio_info = { 97 .read_raw = &lpc32xx_read_raw, 98 }; 99 100 #define LPC32XX_ADC_CHANNEL_BASE(_index) \ 101 .type = IIO_VOLTAGE, \ 102 .indexed = 1, \ 103 .channel = _index, \ 104 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 105 .address = LPC32XXAD_IN * _index, \ 106 .scan_index = _index, 107 108 #define LPC32XX_ADC_CHANNEL(_index) { \ 109 LPC32XX_ADC_CHANNEL_BASE(_index) \ 110 } 111 112 #define LPC32XX_ADC_SCALE_CHANNEL(_index) { \ 113 LPC32XX_ADC_CHANNEL_BASE(_index) \ 114 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 115 } 116 117 static const struct iio_chan_spec lpc32xx_adc_iio_channels[] = { 118 LPC32XX_ADC_CHANNEL(0), 119 LPC32XX_ADC_CHANNEL(1), 120 LPC32XX_ADC_CHANNEL(2), 121 }; 122 123 static const struct iio_chan_spec lpc32xx_adc_iio_scale_channels[] = { 124 LPC32XX_ADC_SCALE_CHANNEL(0), 125 LPC32XX_ADC_SCALE_CHANNEL(1), 126 LPC32XX_ADC_SCALE_CHANNEL(2), 127 }; 128 129 static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id) 130 { 131 struct lpc32xx_adc_state *st = dev_id; 132 133 /* Read value and clear irq */ 134 st->value = __raw_readl(LPC32XXAD_VALUE(st->adc_base)) & 135 LPC32XXAD_VALUE_MASK; 136 complete(&st->completion); 137 138 return IRQ_HANDLED; 139 } 140 141 static int lpc32xx_adc_probe(struct platform_device *pdev) 142 { 143 struct lpc32xx_adc_state *st = NULL; 144 struct resource *res; 145 int retval = -ENODEV; 146 struct iio_dev *iodev = NULL; 147 int irq; 148 149 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 150 if (!res) { 151 dev_err(&pdev->dev, "failed to get platform I/O memory\n"); 152 return -ENXIO; 153 } 154 155 iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); 156 if (!iodev) 157 return -ENOMEM; 158 159 st = iio_priv(iodev); 160 161 st->adc_base = devm_ioremap(&pdev->dev, res->start, 162 resource_size(res)); 163 if (!st->adc_base) { 164 dev_err(&pdev->dev, "failed mapping memory\n"); 165 return -EBUSY; 166 } 167 168 st->clk = devm_clk_get(&pdev->dev, NULL); 169 if (IS_ERR(st->clk)) { 170 dev_err(&pdev->dev, "failed getting clock\n"); 171 return PTR_ERR(st->clk); 172 } 173 174 irq = platform_get_irq(pdev, 0); 175 if (irq <= 0) { 176 dev_err(&pdev->dev, "failed getting interrupt resource\n"); 177 return -ENXIO; 178 } 179 180 retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0, 181 LPC32XXAD_NAME, st); 182 if (retval < 0) { 183 dev_err(&pdev->dev, "failed requesting interrupt\n"); 184 return retval; 185 } 186 187 st->vref = devm_regulator_get(&pdev->dev, "vref"); 188 if (IS_ERR(st->vref)) { 189 iodev->channels = lpc32xx_adc_iio_channels; 190 dev_info(&pdev->dev, 191 "Missing vref regulator: No scaling available\n"); 192 } else { 193 iodev->channels = lpc32xx_adc_iio_scale_channels; 194 } 195 196 platform_set_drvdata(pdev, iodev); 197 198 init_completion(&st->completion); 199 200 iodev->name = LPC32XXAD_NAME; 201 iodev->dev.parent = &pdev->dev; 202 iodev->info = &lpc32xx_adc_iio_info; 203 iodev->modes = INDIO_DIRECT_MODE; 204 iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels); 205 206 retval = devm_iio_device_register(&pdev->dev, iodev); 207 if (retval) 208 return retval; 209 210 dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq); 211 212 return 0; 213 } 214 215 #ifdef CONFIG_OF 216 static const struct of_device_id lpc32xx_adc_match[] = { 217 { .compatible = "nxp,lpc3220-adc" }, 218 {}, 219 }; 220 MODULE_DEVICE_TABLE(of, lpc32xx_adc_match); 221 #endif 222 223 static struct platform_driver lpc32xx_adc_driver = { 224 .probe = lpc32xx_adc_probe, 225 .driver = { 226 .name = LPC32XXAD_NAME, 227 .of_match_table = of_match_ptr(lpc32xx_adc_match), 228 }, 229 }; 230 231 module_platform_driver(lpc32xx_adc_driver); 232 233 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); 234 MODULE_DESCRIPTION("LPC32XX ADC driver"); 235 MODULE_LICENSE("GPL"); 236