diff options
Diffstat (limited to 'drivers/iio/adc/ti_am335x_adc.c')
| -rw-r--r-- | drivers/iio/adc/ti_am335x_adc.c | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c new file mode 100644 index 000000000..a0e7161f0 --- /dev/null +++ b/drivers/iio/adc/ti_am335x_adc.c @@ -0,0 +1,547 @@ +/* + * TI ADC MFD driver + * + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/iio/iio.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/iio/machine.h> +#include <linux/iio/driver.h> + +#include <linux/mfd/ti_am335x_tscadc.h> +#include <linux/iio/buffer.h> +#include <linux/iio/kfifo_buf.h> + +struct tiadc_device { + struct ti_tscadc_dev *mfd_tscadc; + int channels; + u8 channel_line[8]; + u8 channel_step[8]; + int buffer_en_ch_steps; + u16 data[8]; +}; + +static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg) +{ + return readl(adc->mfd_tscadc->tscadc_base + reg); +} + +static void tiadc_writel(struct tiadc_device *adc, unsigned int reg, + unsigned int val) +{ + writel(val, adc->mfd_tscadc->tscadc_base + reg); +} + +static u32 get_adc_step_mask(struct tiadc_device *adc_dev) +{ + u32 step_en; + + step_en = ((1 << adc_dev->channels) - 1); + step_en <<= TOTAL_STEPS - adc_dev->channels + 1; + return step_en; +} + +static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev, + struct iio_chan_spec const *chan) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) { + if (chan->channel == adc_dev->channel_line[i]) { + u32 step; + + step = adc_dev->channel_step[i]; + /* +1 for the charger */ + return 1 << (step + 1); + } + } + WARN_ON(1); + return 0; +} + +static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan) +{ + return 1 << adc_dev->channel_step[chan]; +} + +static void tiadc_step_config(struct iio_dev *indio_dev) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + unsigned int stepconfig; + int i, steps = 0; + + /* + * There are 16 configurable steps and 8 analog input + * lines available which are shared between Touchscreen and ADC. + * + * Steps forwards i.e. from 0 towards 16 are used by ADC + * depending on number of input lines needed. + * Channel would represent which analog input + * needs to be given to ADC to digitalize data. + */ + + if (iio_buffer_enabled(indio_dev)) + stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1 + | STEPCONFIG_MODE_SWCNT; + else + stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; + + for (i = 0; i < adc_dev->channels; i++) { + int chan; + + chan = adc_dev->channel_line[i]; + tiadc_writel(adc_dev, REG_STEPCONFIG(steps), + stepconfig | STEPCONFIG_INP(chan)); + tiadc_writel(adc_dev, REG_STEPDELAY(steps), + STEPCONFIG_OPENDLY); + adc_dev->channel_step[i] = steps; + steps++; + } +} + +static irqreturn_t tiadc_irq_h(int irq, void *private) +{ + struct iio_dev *indio_dev = private; + struct tiadc_device *adc_dev = iio_priv(indio_dev); + unsigned int status, config; + status = tiadc_readl(adc_dev, REG_IRQSTATUS); + + /* + * ADC and touchscreen share the IRQ line. + * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only + */ + if (status & IRQENB_FIFO1OVRRUN) { + /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */ + config = tiadc_readl(adc_dev, REG_CTRL); + config &= ~(CNTRLREG_TSCSSENB); + tiadc_writel(adc_dev, REG_CTRL, config); + tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN + | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES); + tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB)); + return IRQ_HANDLED; + } else if (status & IRQENB_FIFO1THRES) { + /* Disable irq and wake worker thread */ + tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES); + return IRQ_WAKE_THREAD; + } + + return IRQ_NONE; +} + +static irqreturn_t tiadc_worker_h(int irq, void *private) +{ + struct iio_dev *indio_dev = private; + struct tiadc_device *adc_dev = iio_priv(indio_dev); + int i, k, fifo1count, read; + u16 *data = adc_dev->data; + + fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); + for (k = 0; k < fifo1count; k = k + i) { + for (i = 0; i < (indio_dev->scan_bytes)/2; i++) { + read = tiadc_readl(adc_dev, REG_FIFO1); + data[i] = read & FIFOREAD_DATA_MASK; + } + iio_push_to_buffers(indio_dev, (u8 *) data); + } + + tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES); + tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES); + + return IRQ_HANDLED; +} + +static int tiadc_buffer_preenable(struct iio_dev *indio_dev) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + int i, fifo1count, read; + + tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | + IRQENB_FIFO1OVRRUN | + IRQENB_FIFO1UNDRFLW)); + + /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */ + fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); + for (i = 0; i < fifo1count; i++) + read = tiadc_readl(adc_dev, REG_FIFO1); + + return 0; +} + +static int tiadc_buffer_postenable(struct iio_dev *indio_dev) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + unsigned int enb = 0; + u8 bit; + + tiadc_step_config(indio_dev); + for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) + enb |= (get_adc_step_bit(adc_dev, bit) << 1); + adc_dev->buffer_en_ch_steps = enb; + + am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb); + + tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES + | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); + tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES + | IRQENB_FIFO1OVRRUN); + + return 0; +} + +static int tiadc_buffer_predisable(struct iio_dev *indio_dev) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + int fifo1count, i, read; + + tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | + IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW)); + am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps); + adc_dev->buffer_en_ch_steps = 0; + + /* Flush FIFO of leftover data in the time it takes to disable adc */ + fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); + for (i = 0; i < fifo1count; i++) + read = tiadc_readl(adc_dev, REG_FIFO1); + + return 0; +} + +static int tiadc_buffer_postdisable(struct iio_dev *indio_dev) +{ + tiadc_step_config(indio_dev); + + return 0; +} + +static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = { + .preenable = &tiadc_buffer_preenable, + .postenable = &tiadc_buffer_postenable, + .predisable = &tiadc_buffer_predisable, + .postdisable = &tiadc_buffer_postdisable, +}; + +static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev, + irqreturn_t (*pollfunc_bh)(int irq, void *p), + irqreturn_t (*pollfunc_th)(int irq, void *p), + int irq, + unsigned long flags, + const struct iio_buffer_setup_ops *setup_ops) +{ + struct iio_buffer *buffer; + int ret; + + buffer = iio_kfifo_allocate(); + if (!buffer) + return -ENOMEM; + + iio_device_attach_buffer(indio_dev, buffer); + + ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh, + flags, indio_dev->name, indio_dev); + if (ret) + goto error_kfifo_free; + + indio_dev->setup_ops = setup_ops; + indio_dev->modes |= INDIO_BUFFER_HARDWARE; + + return 0; + +error_kfifo_free: + iio_kfifo_free(indio_dev->buffer); + return ret; +} + +static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + + free_irq(adc_dev->mfd_tscadc->irq, indio_dev); + iio_kfifo_free(indio_dev->buffer); +} + + +static const char * const chan_name_ain[] = { + "AIN0", + "AIN1", + "AIN2", + "AIN3", + "AIN4", + "AIN5", + "AIN6", + "AIN7", +}; + +static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + struct iio_chan_spec *chan_array; + struct iio_chan_spec *chan; + int i; + + indio_dev->num_channels = channels; + chan_array = kcalloc(channels, + sizeof(struct iio_chan_spec), GFP_KERNEL); + if (chan_array == NULL) + return -ENOMEM; + + chan = chan_array; + for (i = 0; i < channels; i++, chan++) { + + chan->type = IIO_VOLTAGE; + chan->indexed = 1; + chan->channel = adc_dev->channel_line[i]; + chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); + chan->datasheet_name = chan_name_ain[chan->channel]; + chan->scan_index = i; + chan->scan_type.sign = 'u'; + chan->scan_type.realbits = 12; + chan->scan_type.storagebits = 16; + } + + indio_dev->channels = chan_array; + + return 0; +} + +static void tiadc_channels_remove(struct iio_dev *indio_dev) +{ + kfree(indio_dev->channels); +} + +static int tiadc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct tiadc_device *adc_dev = iio_priv(indio_dev); + int i, map_val; + unsigned int fifo1count, read, stepid; + bool found = false; + u32 step_en; + unsigned long timeout; + + if (iio_buffer_enabled(indio_dev)) + return -EBUSY; + + step_en = get_adc_chan_step_mask(adc_dev, chan); + if (!step_en) + return -EINVAL; + + fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); + while (fifo1count--) + tiadc_readl(adc_dev, REG_FIFO1); + + am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en); + + timeout = jiffies + usecs_to_jiffies + (IDLE_TIMEOUT * adc_dev->channels); + /* Wait for Fifo threshold interrupt */ + while (1) { + fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); + if (fifo1count) + break; + + if (time_after(jiffies, timeout)) { + am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); + return -EAGAIN; + } + } + map_val = adc_dev->channel_step[chan->scan_index]; + + /* + * We check the complete FIFO. We programmed just one entry but in case + * something went wrong we left empty handed (-EAGAIN previously) and + * then the value apeared somehow in the FIFO we would have two entries. + * Therefore we read every item and keep only the latest version of the + * requested channel. + */ + for (i = 0; i < fifo1count; i++) { + read = tiadc_readl(adc_dev, REG_FIFO1); + stepid = read & FIFOREAD_CHNLID_MASK; + stepid = stepid >> 0x10; + + if (stepid == map_val) { + read = read & FIFOREAD_DATA_MASK; + found = true; + *val = (u16) read; + } + } + am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); + + if (found == false) + return -EBUSY; + return IIO_VAL_INT; +} + +static const struct iio_info tiadc_info = { + .read_raw = &tiadc_read_raw, + .driver_module = THIS_MODULE, +}; + +static int tiadc_probe(struct platform_device *pdev) +{ + struct iio_dev *indio_dev; + struct tiadc_device *adc_dev; + struct device_node *node = pdev->dev.of_node; + struct property *prop; + const __be32 *cur; + int err; + u32 val; + int channels = 0; + + if (!node) { + dev_err(&pdev->dev, "Could not find valid DT data.\n"); + return -EINVAL; + } + + indio_dev = devm_iio_device_alloc(&pdev->dev, + sizeof(struct tiadc_device)); + if (indio_dev == NULL) { + dev_err(&pdev->dev, "failed to allocate iio device\n"); + return -ENOMEM; + } + adc_dev = iio_priv(indio_dev); + + adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); + + of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { + adc_dev->channel_line[channels] = val; + channels++; + } + adc_dev->channels = channels; + + indio_dev->dev.parent = &pdev->dev; + indio_dev->name = dev_name(&pdev->dev); + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &tiadc_info; + + tiadc_step_config(indio_dev); + tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); + + err = tiadc_channel_init(indio_dev, adc_dev->channels); + if (err < 0) + return err; + + err = tiadc_iio_buffered_hardware_setup(indio_dev, + &tiadc_worker_h, + &tiadc_irq_h, + adc_dev->mfd_tscadc->irq, + IRQF_SHARED, + &tiadc_buffer_setup_ops); + + if (err) + goto err_free_channels; + + err = iio_device_register(indio_dev); + if (err) + goto err_buffer_unregister; + + platform_set_drvdata(pdev, indio_dev); + + return 0; + +err_buffer_unregister: + tiadc_iio_buffered_hardware_remove(indio_dev); +err_free_channels: + tiadc_channels_remove(indio_dev); + return err; +} + +static int tiadc_remove(struct platform_device *pdev) +{ + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + struct tiadc_device *adc_dev = iio_priv(indio_dev); + u32 step_en; + + iio_device_unregister(indio_dev); + tiadc_iio_buffered_hardware_remove(indio_dev); + tiadc_channels_remove(indio_dev); + + step_en = get_adc_step_mask(adc_dev); + am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); + + return 0; +} + +#ifdef CONFIG_PM +static int tiadc_suspend(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct tiadc_device *adc_dev = iio_priv(indio_dev); + struct ti_tscadc_dev *tscadc_dev; + unsigned int idle; + + tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); + if (!device_may_wakeup(tscadc_dev->dev)) { + idle = tiadc_readl(adc_dev, REG_CTRL); + idle &= ~(CNTRLREG_TSCSSENB); + tiadc_writel(adc_dev, REG_CTRL, (idle | + CNTRLREG_POWERDOWN)); + } + + return 0; +} + +static int tiadc_resume(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct tiadc_device *adc_dev = iio_priv(indio_dev); + unsigned int restore; + + /* Make sure ADC is powered up */ + restore = tiadc_readl(adc_dev, REG_CTRL); + restore &= ~(CNTRLREG_POWERDOWN); + tiadc_writel(adc_dev, REG_CTRL, restore); + + tiadc_step_config(indio_dev); + am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, + adc_dev->buffer_en_ch_steps); + return 0; +} + +static const struct dev_pm_ops tiadc_pm_ops = { + .suspend = tiadc_suspend, + .resume = tiadc_resume, +}; +#define TIADC_PM_OPS (&tiadc_pm_ops) +#else +#define TIADC_PM_OPS NULL +#endif + +static const struct of_device_id ti_adc_dt_ids[] = { + { .compatible = "ti,am3359-adc", }, + { } +}; +MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); + +static struct platform_driver tiadc_driver = { + .driver = { + .name = "TI-am335x-adc", + .pm = TIADC_PM_OPS, + .of_match_table = ti_adc_dt_ids, + }, + .probe = tiadc_probe, + .remove = tiadc_remove, +}; +module_platform_driver(tiadc_driver); + +MODULE_DESCRIPTION("TI ADC controller driver"); +MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); +MODULE_LICENSE("GPL"); |