Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 1 | /* |
| 2 | * TI ADC MFD driver |
| 3 | * |
| 4 | * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License as |
| 8 | * published by the Free Software Foundation version 2. |
| 9 | * |
| 10 | * This program is distributed "as is" WITHOUT ANY WARRANTY of any |
| 11 | * kind, whether express or implied; without even the implied warranty |
| 12 | * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/kernel.h> |
| 18 | #include <linux/err.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/slab.h> |
| 21 | #include <linux/interrupt.h> |
| 22 | #include <linux/platform_device.h> |
| 23 | #include <linux/io.h> |
| 24 | #include <linux/iio/iio.h> |
| 25 | |
| 26 | #include <linux/mfd/ti_am335x_tscadc.h> |
| 27 | #include <linux/platform_data/ti_am335x_adc.h> |
| 28 | |
| 29 | struct tiadc_device { |
| 30 | struct ti_tscadc_dev *mfd_tscadc; |
| 31 | int channels; |
| 32 | }; |
| 33 | |
| 34 | static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg) |
| 35 | { |
| 36 | return readl(adc->mfd_tscadc->tscadc_base + reg); |
| 37 | } |
| 38 | |
| 39 | static void tiadc_writel(struct tiadc_device *adc, unsigned int reg, |
| 40 | unsigned int val) |
| 41 | { |
| 42 | writel(val, adc->mfd_tscadc->tscadc_base + reg); |
| 43 | } |
| 44 | |
Patil, Rachna | abeccee | 2013-01-24 03:45:05 +0000 | [diff] [blame^] | 45 | static u32 get_adc_step_mask(struct tiadc_device *adc_dev) |
| 46 | { |
| 47 | u32 step_en; |
| 48 | |
| 49 | step_en = ((1 << adc_dev->channels) - 1); |
| 50 | step_en <<= TOTAL_STEPS - adc_dev->channels + 1; |
| 51 | return step_en; |
| 52 | } |
| 53 | |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 54 | static void tiadc_step_config(struct tiadc_device *adc_dev) |
| 55 | { |
| 56 | unsigned int stepconfig; |
| 57 | int i, channels = 0, steps; |
Patil, Rachna | abeccee | 2013-01-24 03:45:05 +0000 | [diff] [blame^] | 58 | u32 step_en; |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 59 | |
| 60 | /* |
| 61 | * There are 16 configurable steps and 8 analog input |
| 62 | * lines available which are shared between Touchscreen and ADC. |
| 63 | * |
| 64 | * Steps backwards i.e. from 16 towards 0 are used by ADC |
| 65 | * depending on number of input lines needed. |
| 66 | * Channel would represent which analog input |
| 67 | * needs to be given to ADC to digitalize data. |
| 68 | */ |
| 69 | |
| 70 | steps = TOTAL_STEPS - adc_dev->channels; |
| 71 | channels = TOTAL_CHANNELS - adc_dev->channels; |
| 72 | |
| 73 | stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; |
| 74 | |
| 75 | for (i = (steps + 1); i <= TOTAL_STEPS; i++) { |
| 76 | tiadc_writel(adc_dev, REG_STEPCONFIG(i), |
| 77 | stepconfig | STEPCONFIG_INP(channels)); |
| 78 | tiadc_writel(adc_dev, REG_STEPDELAY(i), |
| 79 | STEPCONFIG_OPENDLY); |
| 80 | channels++; |
| 81 | } |
Patil, Rachna | abeccee | 2013-01-24 03:45:05 +0000 | [diff] [blame^] | 82 | step_en = get_adc_step_mask(adc_dev); |
| 83 | am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 84 | } |
| 85 | |
| 86 | static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) |
| 87 | { |
| 88 | struct iio_chan_spec *chan_array; |
| 89 | int i; |
| 90 | |
| 91 | indio_dev->num_channels = channels; |
| 92 | chan_array = kcalloc(indio_dev->num_channels, |
| 93 | sizeof(struct iio_chan_spec), GFP_KERNEL); |
| 94 | |
| 95 | if (chan_array == NULL) |
| 96 | return -ENOMEM; |
| 97 | |
| 98 | for (i = 0; i < (indio_dev->num_channels); i++) { |
| 99 | struct iio_chan_spec *chan = chan_array + i; |
| 100 | chan->type = IIO_VOLTAGE; |
| 101 | chan->indexed = 1; |
| 102 | chan->channel = i; |
Jonathan Cameron | 6c57252 | 2013-02-27 19:07:18 +0000 | [diff] [blame] | 103 | chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 104 | } |
| 105 | |
| 106 | indio_dev->channels = chan_array; |
| 107 | |
| 108 | return indio_dev->num_channels; |
| 109 | } |
| 110 | |
| 111 | static void tiadc_channels_remove(struct iio_dev *indio_dev) |
| 112 | { |
| 113 | kfree(indio_dev->channels); |
| 114 | } |
| 115 | |
| 116 | static int tiadc_read_raw(struct iio_dev *indio_dev, |
| 117 | struct iio_chan_spec const *chan, |
| 118 | int *val, int *val2, long mask) |
| 119 | { |
| 120 | struct tiadc_device *adc_dev = iio_priv(indio_dev); |
| 121 | int i; |
| 122 | unsigned int fifo1count, readx1; |
| 123 | |
| 124 | /* |
| 125 | * When the sub-system is first enabled, |
| 126 | * the sequencer will always start with the |
| 127 | * lowest step (1) and continue until step (16). |
| 128 | * For ex: If we have enabled 4 ADC channels and |
| 129 | * currently use only 1 out of them, the |
| 130 | * sequencer still configures all the 4 steps, |
| 131 | * leading to 3 unwanted data. |
| 132 | * Hence we need to flush out this data. |
| 133 | */ |
| 134 | |
| 135 | fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); |
| 136 | for (i = 0; i < fifo1count; i++) { |
| 137 | readx1 = tiadc_readl(adc_dev, REG_FIFO1); |
| 138 | if (i == chan->channel) |
| 139 | *val = readx1 & 0xfff; |
| 140 | } |
Patil, Rachna | abeccee | 2013-01-24 03:45:05 +0000 | [diff] [blame^] | 141 | am335x_tsc_se_update(adc_dev->mfd_tscadc); |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 142 | |
| 143 | return IIO_VAL_INT; |
| 144 | } |
| 145 | |
| 146 | static const struct iio_info tiadc_info = { |
| 147 | .read_raw = &tiadc_read_raw, |
| 148 | }; |
| 149 | |
Greg Kroah-Hartman | fc52692 | 2012-12-21 13:21:43 -0800 | [diff] [blame] | 150 | static int tiadc_probe(struct platform_device *pdev) |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 151 | { |
| 152 | struct iio_dev *indio_dev; |
| 153 | struct tiadc_device *adc_dev; |
Sebastian Andrzej Siewior | a9bce1b | 2013-06-05 16:13:47 +0200 | [diff] [blame] | 154 | struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev); |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 155 | struct mfd_tscadc_board *pdata; |
| 156 | int err; |
| 157 | |
| 158 | pdata = tscadc_dev->dev->platform_data; |
| 159 | if (!pdata || !pdata->adc_init) { |
| 160 | dev_err(&pdev->dev, "Could not find platform data\n"); |
| 161 | return -EINVAL; |
| 162 | } |
| 163 | |
| 164 | indio_dev = iio_device_alloc(sizeof(struct tiadc_device)); |
| 165 | if (indio_dev == NULL) { |
| 166 | dev_err(&pdev->dev, "failed to allocate iio device\n"); |
| 167 | err = -ENOMEM; |
| 168 | goto err_ret; |
| 169 | } |
| 170 | adc_dev = iio_priv(indio_dev); |
| 171 | |
| 172 | adc_dev->mfd_tscadc = tscadc_dev; |
| 173 | adc_dev->channels = pdata->adc_init->adc_channels; |
| 174 | |
| 175 | indio_dev->dev.parent = &pdev->dev; |
| 176 | indio_dev->name = dev_name(&pdev->dev); |
| 177 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 178 | indio_dev->info = &tiadc_info; |
| 179 | |
| 180 | tiadc_step_config(adc_dev); |
| 181 | |
| 182 | err = tiadc_channel_init(indio_dev, adc_dev->channels); |
| 183 | if (err < 0) |
| 184 | goto err_free_device; |
| 185 | |
| 186 | err = iio_device_register(indio_dev); |
| 187 | if (err) |
| 188 | goto err_free_channels; |
| 189 | |
| 190 | platform_set_drvdata(pdev, indio_dev); |
| 191 | |
| 192 | return 0; |
| 193 | |
| 194 | err_free_channels: |
| 195 | tiadc_channels_remove(indio_dev); |
| 196 | err_free_device: |
| 197 | iio_device_free(indio_dev); |
| 198 | err_ret: |
| 199 | return err; |
| 200 | } |
| 201 | |
Greg Kroah-Hartman | fc52692 | 2012-12-21 13:21:43 -0800 | [diff] [blame] | 202 | static int tiadc_remove(struct platform_device *pdev) |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 203 | { |
| 204 | struct iio_dev *indio_dev = platform_get_drvdata(pdev); |
Patil, Rachna | abeccee | 2013-01-24 03:45:05 +0000 | [diff] [blame^] | 205 | struct tiadc_device *adc_dev = iio_priv(indio_dev); |
| 206 | u32 step_en; |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 207 | |
| 208 | iio_device_unregister(indio_dev); |
| 209 | tiadc_channels_remove(indio_dev); |
| 210 | |
Patil, Rachna | abeccee | 2013-01-24 03:45:05 +0000 | [diff] [blame^] | 211 | step_en = get_adc_step_mask(adc_dev); |
| 212 | am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); |
| 213 | |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 214 | iio_device_free(indio_dev); |
| 215 | |
| 216 | return 0; |
| 217 | } |
| 218 | |
| 219 | #ifdef CONFIG_PM |
| 220 | static int tiadc_suspend(struct device *dev) |
| 221 | { |
| 222 | struct iio_dev *indio_dev = dev_get_drvdata(dev); |
| 223 | struct tiadc_device *adc_dev = iio_priv(indio_dev); |
Sebastian Andrzej Siewior | a9bce1b | 2013-06-05 16:13:47 +0200 | [diff] [blame] | 224 | struct ti_tscadc_dev *tscadc_dev; |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 225 | unsigned int idle; |
| 226 | |
Sebastian Andrzej Siewior | a9bce1b | 2013-06-05 16:13:47 +0200 | [diff] [blame] | 227 | tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 228 | if (!device_may_wakeup(tscadc_dev->dev)) { |
| 229 | idle = tiadc_readl(adc_dev, REG_CTRL); |
| 230 | idle &= ~(CNTRLREG_TSCSSENB); |
| 231 | tiadc_writel(adc_dev, REG_CTRL, (idle | |
| 232 | CNTRLREG_POWERDOWN)); |
| 233 | } |
| 234 | |
| 235 | return 0; |
| 236 | } |
| 237 | |
| 238 | static int tiadc_resume(struct device *dev) |
| 239 | { |
| 240 | struct iio_dev *indio_dev = dev_get_drvdata(dev); |
| 241 | struct tiadc_device *adc_dev = iio_priv(indio_dev); |
| 242 | unsigned int restore; |
| 243 | |
| 244 | /* Make sure ADC is powered up */ |
| 245 | restore = tiadc_readl(adc_dev, REG_CTRL); |
| 246 | restore &= ~(CNTRLREG_POWERDOWN); |
| 247 | tiadc_writel(adc_dev, REG_CTRL, restore); |
| 248 | |
| 249 | tiadc_step_config(adc_dev); |
| 250 | |
| 251 | return 0; |
| 252 | } |
| 253 | |
| 254 | static const struct dev_pm_ops tiadc_pm_ops = { |
| 255 | .suspend = tiadc_suspend, |
| 256 | .resume = tiadc_resume, |
| 257 | }; |
| 258 | #define TIADC_PM_OPS (&tiadc_pm_ops) |
| 259 | #else |
| 260 | #define TIADC_PM_OPS NULL |
| 261 | #endif |
| 262 | |
| 263 | static struct platform_driver tiadc_driver = { |
| 264 | .driver = { |
| 265 | .name = "tiadc", |
| 266 | .owner = THIS_MODULE, |
| 267 | .pm = TIADC_PM_OPS, |
| 268 | }, |
| 269 | .probe = tiadc_probe, |
Greg Kroah-Hartman | fc52692 | 2012-12-21 13:21:43 -0800 | [diff] [blame] | 270 | .remove = tiadc_remove, |
Patil, Rachna | 5e53a69 | 2012-10-16 12:55:45 +0530 | [diff] [blame] | 271 | }; |
| 272 | |
| 273 | module_platform_driver(tiadc_driver); |
| 274 | |
| 275 | MODULE_DESCRIPTION("TI ADC controller driver"); |
| 276 | MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); |
| 277 | MODULE_LICENSE("GPL"); |