Input: ads7846 - add possibility to use external vref on ads7846
Just set vref_mv in your platform config to use external vref. Otherwise the internal one is used. Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
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@ -109,6 +109,7 @@ struct ads7846 {
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u16 pressure_max;
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bool swap_xy;
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bool use_internal;
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struct ads7846_packet *packet;
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@ -300,7 +301,6 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
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struct ads7846 *ts = dev_get_drvdata(dev);
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struct ser_req *req;
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int status;
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int use_internal;
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req = kzalloc(sizeof *req, GFP_KERNEL);
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if (!req)
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@ -308,11 +308,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
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spi_message_init(&req->msg);
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/* FIXME boards with ads7846 might use external vref instead ... */
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use_internal = (ts->model == 7846);
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/* maybe turn on internal vREF, and let it settle */
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if (use_internal) {
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if (ts->use_internal) {
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req->ref_on = REF_ON;
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req->xfer[0].tx_buf = &req->ref_on;
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req->xfer[0].len = 1;
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@ -324,8 +321,14 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
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/* for 1uF, settle for 800 usec; no cap, 100 usec. */
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req->xfer[1].delay_usecs = ts->vref_delay_usecs;
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spi_message_add_tail(&req->xfer[1], &req->msg);
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/* Enable reference voltage */
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command |= ADS_PD10_REF_ON;
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}
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/* Enable ADC in every case */
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command |= ADS_PD10_ADC_ON;
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/* take sample */
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req->command = (u8) command;
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req->xfer[2].tx_buf = &req->command;
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@ -409,7 +412,7 @@ name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
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{ \
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struct ads7846 *ts = dev_get_drvdata(dev); \
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ssize_t v = ads7846_read12_ser(dev, \
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READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
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READ_12BIT_SER(var)); \
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if (v < 0) \
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return v; \
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return sprintf(buf, "%u\n", adjust(ts, v)); \
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@ -502,6 +505,7 @@ static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
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if (!ts->vref_mv) {
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dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
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ts->vref_mv = 2500;
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ts->use_internal = true;
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}
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break;
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case 7845:
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@ -1333,8 +1337,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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if (ts->model == 7845)
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ads7845_read12_ser(&spi->dev, PWRDOWN);
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else
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(void) ads7846_read12_ser(&spi->dev,
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READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
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(void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
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err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
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if (err)
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@ -14,7 +14,8 @@ enum ads7846_filter {
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struct ads7846_platform_data {
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u16 model; /* 7843, 7845, 7846, 7873. */
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u16 vref_delay_usecs; /* 0 for external vref; etc */
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u16 vref_mv; /* external vref value, milliVolts */
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u16 vref_mv; /* external vref value, milliVolts
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* ads7846: if 0, use internal vref */
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bool keep_vref_on; /* set to keep vref on for differential
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* measurements as well */
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bool swap_xy; /* swap x and y axes */
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