iio: adc: mcp3911: add support for buffers

Add support for buffers to make the driver fit for more use cases.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220815061625.35568-6-marcus.folkesson@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 56e3ca3..791612c 100644 (file)
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -732,6 +732,8 @@ config MCP3422
 config MCP3911
        tristate "Microchip Technology MCP3911 driver"
        depends on SPI
+       select IIO_BUFFER
+       select IIO_TRIGGERED_BUFFER
        help
          Say yes here to build support for Microchip Technology's MCP3911
          analog to digital converter.

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 15b3e5b..15290a6 100644 (file)
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -5,16 +5,25 @@
  * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
  * Copyright (C) 2018 Kent Gustavsson <kent@minoris.se>
  */
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
-#include <linux/iio/iio.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/property.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
 
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/trigger.h>
+
+#include <asm/unaligned.h>
+
 #define MCP3911_REG_CHANNEL0           0x00
 #define MCP3911_REG_CHANNEL1           0x03
 #define MCP3911_REG_MOD                        0x06
@@ -22,6 +31,7 @@
 #define MCP3911_REG_GAIN               0x09
 
 #define MCP3911_REG_STATUSCOM          0x0a
+#define MCP3911_STATUSCOM_READ         GENMASK(7, 6)
 #define MCP3911_STATUSCOM_CH1_24WIDTH  BIT(4)
 #define MCP3911_STATUSCOM_CH0_24WIDTH  BIT(3)
 #define MCP3911_STATUSCOM_EN_OFFCAL    BIT(2)
@@ -54,6 +64,13 @@ struct mcp3911 {
        struct regulator *vref;
        struct clk *clki;
        u32 dev_addr;
+       struct {
+               u32 channels[MCP3911_NUM_CHANNELS];
+               s64 ts __aligned(8);
+       } scan;
+
+       u8 tx_buf __aligned(IIO_DMA_MINALIGN);
+       u8 rx_buf[MCP3911_NUM_CHANNELS * 3];
 };
 
 static int mcp3911_read(struct mcp3911 *adc, u8 reg, u32 *val, u8 len)
@@ -196,16 +213,66 @@ out:
                .type = IIO_VOLTAGE,                            \
                .indexed = 1,                                   \
                .channel = idx,                                 \
+               .scan_index = idx,                              \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
                        BIT(IIO_CHAN_INFO_OFFSET) |             \
                        BIT(IIO_CHAN_INFO_SCALE),               \
+               .scan_type = {                                  \
+                       .sign = 's',                            \
+                       .realbits = 24,                         \
+                       .storagebits = 32,                      \
+                       .endianness = IIO_BE,                   \
+               },                                              \
 }
 
 static const struct iio_chan_spec mcp3911_channels[] = {
        MCP3911_CHAN(0),
        MCP3911_CHAN(1),
+       IIO_CHAN_SOFT_TIMESTAMP(2),
 };
 
+static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
+{
+       struct iio_poll_func *pf = p;
+       struct iio_dev *indio_dev = pf->indio_dev;
+       struct mcp3911 *adc = iio_priv(indio_dev);
+       struct spi_transfer xfer[] = {
+               {
+                       .tx_buf = &adc->tx_buf,
+                       .len = 1,
+               }, {
+                       .rx_buf = adc->rx_buf,
+                       .len = sizeof(adc->rx_buf),
+               },
+       };
+       int scan_index;
+       int i = 0;
+       int ret;
+
+       mutex_lock(&adc->lock);
+       adc->tx_buf = MCP3911_REG_READ(MCP3911_CHANNEL(0), adc->dev_addr);
+       ret = spi_sync_transfer(adc->spi, xfer, ARRAY_SIZE(xfer));
+       if (ret < 0) {
+               dev_warn(&adc->spi->dev,
+                               "failed to get conversion data\n");
+               goto out;
+       }
+
+       for_each_set_bit(scan_index, indio_dev->active_scan_mask, indio_dev->masklength) {
+               const struct iio_chan_spec *scan_chan = &indio_dev->channels[scan_index];
+
+               adc->scan.channels[i] = get_unaligned_be24(&adc->rx_buf[scan_chan->channel * 3]);
+               i++;
+       }
+       iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
+                                          iio_get_time_ns(indio_dev));
+out:
+       mutex_unlock(&adc->lock);
+       iio_trigger_notify_done(indio_dev->trig);
+
+       return IRQ_HANDLED;
+}
+
 static const struct iio_info mcp3911_info = {
        .read_raw = mcp3911_read_raw,
        .write_raw = mcp3911_write_raw,
@@ -214,7 +281,7 @@ static const struct iio_info mcp3911_info = {
 static int mcp3911_config(struct mcp3911 *adc)
 {
        struct device *dev = &adc->spi->dev;
-       u32 configreg;
+       u32 regval;
        int ret;
 
        ret = device_property_read_u32(dev, "microchip,device-addr", &adc->dev_addr);
@@ -233,29 +300,43 @@ static int mcp3911_config(struct mcp3911 *adc)
        }
        dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr);
 
-       ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &configreg, 2);
+       ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &regval, 2);
        if (ret)
                return ret;
 
+       regval &= ~MCP3911_CONFIG_VREFEXT;
        if (adc->vref) {
                dev_dbg(&adc->spi->dev, "use external voltage reference\n");
-               configreg |= MCP3911_CONFIG_VREFEXT;
+               regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 1);
        } else {
                dev_dbg(&adc->spi->dev,
                        "use internal voltage reference (1.2V)\n");
-               configreg &= ~MCP3911_CONFIG_VREFEXT;
+               regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 0);
        }
 
+       regval &= ~MCP3911_CONFIG_CLKEXT;
        if (adc->clki) {
                dev_dbg(&adc->spi->dev, "use external clock as clocksource\n");
-               configreg |= MCP3911_CONFIG_CLKEXT;
+               regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 1);
        } else {
                dev_dbg(&adc->spi->dev,
                        "use crystal oscillator as clocksource\n");
-               configreg &= ~MCP3911_CONFIG_CLKEXT;
+               regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 0);
        }
 
-       return  mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2);
+       ret = mcp3911_write(adc, MCP3911_REG_CONFIG, regval, 2);
+       if (ret)
+               return ret;
+
+       ret = mcp3911_read(adc, MCP3911_REG_STATUSCOM, &regval, 2);
+       if (ret)
+               return ret;
+
+       /* Address counter incremented, cycle through register types */
+       regval &= ~MCP3911_STATUSCOM_READ;
+       regval |= FIELD_PREP(MCP3911_STATUSCOM_READ, 0x02);
+
+       return  mcp3911_write(adc, MCP3911_REG_STATUSCOM, regval, 2);
 }
 
 static void mcp3911_cleanup_regulator(void *vref)
@@ -324,6 +405,12 @@ static int mcp3911_probe(struct spi_device *spi)
 
        mutex_init(&adc->lock);
 
+       ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+                       NULL,
+                       mcp3911_trigger_handler, NULL);
+       if (ret)
+               return ret;
+
        return devm_iio_device_register(&adc->spi->dev, indio_dev);
 }