iio: adc: tsc2046: add .read_raw support

Add read_raw() support to make use of iio_hwmon and other iio clients.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20220117082852.3370869-1-o.rempel@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
index 098dbca..eb219ff 100644 (file)
--- a/drivers/iio/adc/ti-tsc2046.c
+++ b/drivers/iio/adc/ti-tsc2046.c
@@ -86,6 +86,7 @@
 #define TI_TSC2046_EXT_POLL_CNT                        3
 #define TI_TSC2046_POLL_CNT \
        (TI_TSC2046_MIN_POLL_CNT + TI_TSC2046_EXT_POLL_CNT)
+#define TI_TSC2046_INT_VREF                    2500
 
 /* Represents a HW sample */
 struct tsc2046_adc_atom {
@@ -166,9 +167,6 @@ struct tsc2046_adc_priv {
        struct tsc2046_adc_atom *rx;
        struct tsc2046_adc_atom *tx;
 
-       struct tsc2046_adc_atom *rx_one;
-       struct tsc2046_adc_atom *tx_one;
-
        unsigned int count;
        unsigned int groups;
        u32 effective_speed_hz;
@@ -184,6 +182,8 @@ struct tsc2046_adc_priv {
        .type = IIO_VOLTAGE,                                    \
        .indexed = 1,                                           \
        .channel = index,                                       \
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
+       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
        .datasheet_name = "#name",                              \
        .scan_index = index,                                    \
        .scan_type = {                                          \
@@ -247,6 +247,14 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
        else
                pd = 0;
 
+       switch (ch_idx) {
+       case TI_TSC2046_ADDR_TEMP1:
+       case TI_TSC2046_ADDR_AUX:
+       case TI_TSC2046_ADDR_VBAT:
+       case TI_TSC2046_ADDR_TEMP0:
+               pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON;
+       }
+
        return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
 }
 
@@ -258,16 +266,50 @@ static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf)
 static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx,
                                u32 *effective_speed_hz)
 {
+       struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx];
+       struct tsc2046_adc_atom *rx_buf, *tx_buf;
+       unsigned int val, val_normalized = 0;
+       int ret, i, count_skip = 0, max_count;
        struct spi_transfer xfer;
        struct spi_message msg;
-       int ret;
+       u8 cmd;
+
+       if (!effective_speed_hz) {
+               count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us);
+               max_count = count_skip + ch->oversampling_ratio;
+       } else {
+               max_count = 1;
+       }
+
+       if (sizeof(*tx_buf) * max_count > PAGE_SIZE)
+               return -ENOSPC;
+
+       tx_buf = kcalloc(max_count, sizeof(*tx_buf), GFP_KERNEL);
+       if (!tx_buf)
+               return -ENOMEM;
+
+       rx_buf = kcalloc(max_count, sizeof(*rx_buf), GFP_KERNEL);
+       if (!rx_buf) {
+               ret = -ENOMEM;
+               goto free_tx;
+       }
+
+       /*
+        * Do not enable automatic power down on working samples. Otherwise the
+        * plates will never be completely charged.
+        */
+       cmd = tsc2046_adc_get_cmd(priv, ch_idx, true);
+
+       for (i = 0; i < max_count - 1; i++)
+               tx_buf[i].cmd = cmd;
+
+       /* automatically power down on last sample */
+       tx_buf[i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false);
 
        memset(&xfer, 0, sizeof(xfer));
-       priv->tx_one->cmd = tsc2046_adc_get_cmd(priv, ch_idx, false);
-       priv->tx_one->data = 0;
-       xfer.tx_buf = priv->tx_one;
-       xfer.rx_buf = priv->rx_one;
-       xfer.len = sizeof(*priv->tx_one);
+       xfer.tx_buf = tx_buf;
+       xfer.rx_buf = rx_buf;
+       xfer.len = sizeof(*tx_buf) * max_count;
        spi_message_init_with_transfers(&msg, &xfer, 1);
 
        /*
@@ -278,13 +320,25 @@ static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx,
        if (ret) {
                dev_err_ratelimited(&priv->spi->dev, "SPI transfer failed %pe\n",
                                    ERR_PTR(ret));
-               return ret;
+               goto free_bufs;
        }
 
        if (effective_speed_hz)
                *effective_speed_hz = xfer.effective_speed_hz;
 
-       return tsc2046_adc_get_value(priv->rx_one);
+       for (i = 0; i < max_count - count_skip; i++) {
+               val = tsc2046_adc_get_value(&rx_buf[count_skip + i]);
+               val_normalized += val;
+       }
+
+       ret = DIV_ROUND_UP(val_normalized, max_count - count_skip);
+
+free_bufs:
+       kfree(rx_buf);
+free_tx:
+       kfree(tx_buf);
+
+       return ret;
 }
 
 static size_t tsc2046_adc_group_set_layout(struct tsc2046_adc_priv *priv,
@@ -391,6 +445,37 @@ static irqreturn_t tsc2046_adc_trigger_handler(int irq, void *p)
        return IRQ_HANDLED;
 }
 
+static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,
+                               struct iio_chan_spec const *chan,
+                               int *val, int *val2, long m)
+{
+       struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+       int ret;
+
+       switch (m) {
+       case IIO_CHAN_INFO_RAW:
+               ret = tsc2046_adc_read_one(priv, chan->channel, NULL);
+               if (ret < 0)
+                       return ret;
+
+               *val = ret;
+
+               return IIO_VAL_INT;
+       case IIO_CHAN_INFO_SCALE:
+               /*
+                * Note: the TSC2046 has internal voltage divider on the VBAT
+                * line. This divider can be influenced by external divider.
+                * So, it is better to use external voltage-divider driver
+                * instead, which is calculating complete chain.
+                */
+               *val = TI_TSC2046_INT_VREF;
+               *val2 = chan->scan_type.realbits;
+               return IIO_VAL_FRACTIONAL_LOG2;
+       }
+
+       return -EINVAL;
+}
+
 static int tsc2046_adc_update_scan_mode(struct iio_dev *indio_dev,
                                        const unsigned long *active_scan_mask)
 {
@@ -421,6 +506,7 @@ static int tsc2046_adc_update_scan_mode(struct iio_dev *indio_dev,
 }
 
 static const struct iio_info tsc2046_adc_info = {
+       .read_raw         = tsc2046_adc_read_raw,
        .update_scan_mode = tsc2046_adc_update_scan_mode,
 };
 
@@ -563,16 +649,6 @@ static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv)
        size_t size;
        int ret;
 
-       priv->tx_one = devm_kzalloc(&priv->spi->dev, sizeof(*priv->tx_one),
-                                   GFP_KERNEL);
-       if (!priv->tx_one)
-               return -ENOMEM;
-
-       priv->rx_one = devm_kzalloc(&priv->spi->dev, sizeof(*priv->rx_one),
-                                   GFP_KERNEL);
-       if (!priv->rx_one)
-               return -ENOMEM;
-
        /*
         * Make dummy read to set initial power state and get real SPI clock
         * freq. It seems to be not important which channel is used for this