Merge tag 'iio-for-4.10b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-testing

Jonathan writes:

Second round of new device support, cleanups and fixes for IIO in the 4.10 cycle

This includes two branch merges for elements that may also go via MFD.

New device support
* cros_ec
  - new driver to support these Chrome OS contiguous sensors which are behind
    the Chrome OS embedded controller.  Requires a few minor MFD and chrome
    platform changes.  One follow up fix deals with some dependency issues in
    Kconfig.
* mpu-3050
  - new driver and device tree bindings for this venerable device.
* st_accel
  - support for the lng2dm an

Driver features
* ad7192
  - Add DVdd regulator handling
* ad9832
  - Add DVDD regulator handling
* at91
  - Suspend and resume support
* si7020
  - Device tree bindings
* ti-am335x
  - DMA support - uses dma to accelerate short bursts of read back rather
  than full blown DMA buffer support.  Greatly improved performance.
  Includes an MFD addition to give access to the address needed for DMA.
* tsl2583
  - Device tree bindings

Cleanups and minor fixes
* ad7192
  - Fix regulator naming to match datasheet
  - Handle regulator errors correctly (so as to not break deferred probing)
  - Rename reg variable to reflect which regulator it is
* ad5933
  - Fix regulator naming to match datasheet
  - Handle regulator errors correctly (so as to not break deferred probing)
* ad7746
  - Fix a missing return value (fallout from previous patch set)
* ad7780
  - Fix regulator naming to match datasheet
  - Handle regulator errors correctly (so as to not break deferred probing)
* ad9832
  - Fix regulator naming to match datasheet
  - Handle regulator errors correctly (so as to not break deferred probing)
  - Rename reg regulator to reflect which one it is
* ad9834
  - Fix regulator naming to match datasheet
  - Handle regulator errors correctly (so as to not break deferred probing)
* hts221
  - Remove a duplicated include
* maxim thermocouple
  - Handle a wrong storage side in read function.  Prevent any problems that
  might be introduced by additions to this driver in future.
* tsl2583 - big set from Brian Masney to drive this towards a staging
  graduation.
  - Convert to iio_chan_spec and read_raw / write_raw (in a couple of steps)
  - Improved error handling in various functions
  - Drop redundant power_state custom sysfs attribute.
  - Use IIO_*_ATTR* macros for remaining attributes.
  - Return an error code to userspace on invalid parameters being writen to
    sysfs files.
  - Add locking to various attribute accesses to remove possible races.
  - Add defines for various magic numbers.
  - Use smbus_read_byte_data instead of a write_byte followed by read_byte.
  - Query only relevant registers in probe.
  - Tidy up ordering of code comments.
  - Remove a pointless power off sequence in taos_chip_on.
  - Don't bother shutting down the chip when updating the lux table.
  The table is held entirely in the driver and doesn't effect the chip at all.
  - Drop a redundant i2c call in taos_als_calibrate where the same register
  is read twice in a row.

2 files changed, 173 insertions, 3 deletions

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index bbdac07f4aaa..34b928cefeed 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -30,6 +30,7 @@
 #include <linux/iio/trigger.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
+#include <linux/pinctrl/consumer.h>
 
 /* Registers */
 #define AT91_ADC_CR		0x00		/* Control Register */
@@ -1347,6 +1348,32 @@ static int at91_adc_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int at91_adc_suspend(struct device *dev)
+{
+	struct iio_dev *idev = platform_get_drvdata(to_platform_device(dev));
+	struct at91_adc_state *st = iio_priv(idev);
+
+	pinctrl_pm_select_sleep_state(dev);
+	clk_disable_unprepare(st->clk);
+
+	return 0;
+}
+
+static int at91_adc_resume(struct device *dev)
+{
+	struct iio_dev *idev = platform_get_drvdata(to_platform_device(dev));
+	struct at91_adc_state *st = iio_priv(idev);
+
+	clk_prepare_enable(st->clk);
+	pinctrl_pm_select_default_state(dev);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
+
 static struct at91_adc_caps at91sam9260_caps = {
 	.calc_startup_ticks = calc_startup_ticks_9260,
 	.num_channels = 4,
@@ -1441,6 +1468,7 @@ static struct platform_driver at91_adc_driver = {
 	.driver = {
 		   .name = DRIVER_NAME,
 		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
+		   .pm = &at91_adc_pm_ops,
 	},
 };
 
diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index c3cfacca2541..ad9dec30bb30 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -30,10 +30,28 @@
 #include <linux/iio/buffer.h>
 #include <linux/iio/kfifo_buf.h>
 
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+
+#define DMA_BUFFER_SIZE		SZ_2K
+
+struct tiadc_dma {
+	struct dma_slave_config	conf;
+	struct dma_chan		*chan;
+	dma_addr_t		addr;
+	dma_cookie_t		cookie;
+	u8			*buf;
+	int			current_period;
+	int			period_size;
+	u8			fifo_thresh;
+};
+
 struct tiadc_device {
 	struct ti_tscadc_dev *mfd_tscadc;
+	struct tiadc_dma dma;
 	struct mutex fifo1_lock; /* to protect fifo access */
 	int channels;
+	int total_ch_enabled;
 	u8 channel_line[8];
 	u8 channel_step[8];
 	int buffer_en_ch_steps;
@@ -198,6 +216,67 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
 	return IRQ_HANDLED;
 }
 
+static void tiadc_dma_rx_complete(void *param)
+{
+	struct iio_dev *indio_dev = param;
+	struct tiadc_device *adc_dev = iio_priv(indio_dev);
+	struct tiadc_dma *dma = &adc_dev->dma;
+	u8 *data;
+	int i;
+
+	data = dma->buf + dma->current_period * dma->period_size;
+	dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
+
+	for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) {
+		iio_push_to_buffers(indio_dev, data);
+		data += indio_dev->scan_bytes;
+	}
+}
+
+static int tiadc_start_dma(struct iio_dev *indio_dev)
+{
+	struct tiadc_device *adc_dev = iio_priv(indio_dev);
+	struct tiadc_dma *dma = &adc_dev->dma;
+	struct dma_async_tx_descriptor *desc;
+
+	dma->current_period = 0; /* We start to fill period 0 */
+	/*
+	 * Make the fifo thresh as the multiple of total number of
+	 * channels enabled, so make sure that cyclic DMA period
+	 * length is also a multiple of total number of channels
+	 * enabled. This ensures that no invalid data is reported
+	 * to the stack via iio_push_to_buffers().
+	 */
+	dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1,
+				     adc_dev->total_ch_enabled) - 1;
+	/* Make sure that period length is multiple of fifo thresh level */
+	dma->period_size = rounddown(DMA_BUFFER_SIZE / 2,
+				    (dma->fifo_thresh + 1) * sizeof(u16));
+
+	dma->conf.src_maxburst = dma->fifo_thresh + 1;
+	dmaengine_slave_config(dma->chan, &dma->conf);
+
+	desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
+					 dma->period_size * 2,
+					 dma->period_size, DMA_DEV_TO_MEM,
+					 DMA_PREP_INTERRUPT);
+	if (!desc)
+		return -EBUSY;
+
+	desc->callback = tiadc_dma_rx_complete;
+	desc->callback_param = indio_dev;
+
+	dma->cookie = dmaengine_submit(desc);
+
+	dma_async_issue_pending(dma->chan);
+
+	tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
+	tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
+	tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
+
+	return 0;
+}
+
 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
@@ -218,20 +297,30 @@ static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
+	struct tiadc_dma *dma = &adc_dev->dma;
+	unsigned int irq_enable;
 	unsigned int enb = 0;
 	u8 bit;
 
 	tiadc_step_config(indio_dev);
-	for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
+	for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
 		enb |= (get_adc_step_bit(adc_dev, bit) << 1);
+		adc_dev->total_ch_enabled++;
+	}
 	adc_dev->buffer_en_ch_steps = enb;
 
+	if (dma->chan)
+		tiadc_start_dma(indio_dev);
+
 	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);
+
+	irq_enable = IRQENB_FIFO1OVRRUN;
+	if (!dma->chan)
+		irq_enable |= IRQENB_FIFO1THRES;
+	tiadc_writel(adc_dev,  REG_IRQENABLE, irq_enable);
 
 	return 0;
 }
@@ -239,12 +328,18 @@ static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
+	struct tiadc_dma *dma = &adc_dev->dma;
 	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;
+	adc_dev->total_ch_enabled = 0;
+	if (dma->chan) {
+		tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
+		dmaengine_terminate_async(dma->chan);
+	}
 
 	/* Flush FIFO of leftover data in the time it takes to disable adc */
 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
@@ -430,6 +525,41 @@ static const struct iio_info tiadc_info = {
 	.driver_module = THIS_MODULE,
 };
 
+static int tiadc_request_dma(struct platform_device *pdev,
+			     struct tiadc_device *adc_dev)
+{
+	struct tiadc_dma	*dma = &adc_dev->dma;
+	dma_cap_mask_t		mask;
+
+	/* Default slave configuration parameters */
+	dma->conf.direction = DMA_DEV_TO_MEM;
+	dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+	dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_CYCLIC, mask);
+
+	/* Get a channel for RX */
+	dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1");
+	if (IS_ERR(dma->chan)) {
+		int ret = PTR_ERR(dma->chan);
+
+		dma->chan = NULL;
+		return ret;
+	}
+
+	/* RX buffer */
+	dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
+				      &dma->addr, GFP_KERNEL);
+	if (!dma->buf)
+		goto err;
+
+	return 0;
+err:
+	dma_release_channel(dma->chan);
+	return -ENOMEM;
+}
+
 static int tiadc_parse_dt(struct platform_device *pdev,
 			  struct tiadc_device *adc_dev)
 {
@@ -512,8 +642,14 @@ static int tiadc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, indio_dev);
 
+	err = tiadc_request_dma(pdev, adc_dev);
+	if (err && err == -EPROBE_DEFER)
+		goto err_dma;
+
 	return 0;
 
+err_dma:
+	iio_device_unregister(indio_dev);
 err_buffer_unregister:
 	tiadc_iio_buffered_hardware_remove(indio_dev);
 err_free_channels:
@@ -525,8 +661,14 @@ 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);
+	struct tiadc_dma *dma = &adc_dev->dma;
 	u32 step_en;
 
+	if (dma->chan) {
+		dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
+				  dma->buf, dma->addr);
+		dma_release_channel(dma->chan);
+	}
 	iio_device_unregister(indio_dev);
 	tiadc_iio_buffered_hardware_remove(indio_dev);
 	tiadc_channels_remove(indio_dev);