]> sigrok.org Git - libsigrok.git/blobdiff - hardware/radioshack-dmm/radioshack.c
radioshack-dmm: Move some stuff out of .h file.
[libsigrok.git] / hardware / radioshack-dmm / radioshack.c
index 078160e01aace910ca8a1f40ce595df5327632f0..cb77339c251ada8e82c5f2b189ffb5861c696030 100644 (file)
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <glib.h>
-#include "libsigrok.h"
-#include "libsigrok-internal.h"
-#include "config.h"
-#include "radioshack-dmm.h"
 #include <stdlib.h>
 #include <math.h>
 #include <string.h>
 #include <errno.h>
+#include <glib.h>
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+#include "radioshack-dmm.h"
 
+/* Byte 1 of the packet, and the modes it represents */
+#define IND1_HZ                0x80
+#define IND1_OHM       0x40
+#define IND1_KILO      0x20
+#define IND1_MEGA      0x10
+#define IND1_FARAD     0x08
+#define IND1_AMP       0x04
+#define IND1_VOLT      0x02
+#define IND1_MILI      0x01
+/* Byte 2 of the packet, and the modes it represents */
+#define IND2_MICRO     0x80
+#define IND2_NANO      0x40
+#define IND2_DBM       0x20
+#define IND2_SEC       0x10
+#define IND2_DUTY      0x08
+#define IND2_HFE       0x04
+#define IND2_REL       0x02
+#define IND2_MIN       0x01
+/* Byte 7 of the packet, and the modes it represents */
+#define INFO_BEEP      0x80
+#define INFO_DIODE     0x30
+#define INFO_BAT       0x20
+#define INFO_HOLD      0x10
+#define INFO_NEG       0x08
+#define INFO_AC                0x04
+#define INFO_RS232     0x02
+#define INFO_AUTO      0x01
+/* Instead of a decimal point, digit 4 carries the MAX flag */
+#define DIG4_MAX       0x08
+/* Mask to remove the decimal point from a digit */
+#define DP_MASK                0x08
+
+/* What the LCD values represent */
+#define LCD_0          0xd7
+#define LCD_1          0x50
+#define LCD_2          0xb5
+#define LCD_3          0xf1
+#define LCD_4          0x72
+#define LCD_5          0xe3
+#define LCD_6          0xe7
+#define LCD_7          0x51
+#define LCD_8          0xf7
+#define LCD_9          0xf3
+
+#define LCD_C          0x87
+#define LCD_E
+#define LCD_F
+#define LCD_h          0x66
+#define LCD_H          0x76
+#define LCD_I
+#define LCD_n
+#define LCD_P          0x37
+#define LCD_r
+
+enum {
+       MODE_DC_V       = 0,
+       MODE_AC_V       = 1,
+       MODE_DC_UA      = 2,
+       MODE_DC_MA      = 3,
+       MODE_DC_A       = 4,
+       MODE_AC_UA      = 5,
+       MODE_AC_MA      = 6,
+       MODE_AC_A       = 7,
+       MODE_OHM        = 8,
+       MODE_FARAD      = 9,
+       MODE_HZ         = 10,
+       MODE_VOLT_HZ    = 11,
+       MODE_AMP_HZ     = 12,
+       MODE_DUTY       = 13,
+       MODE_VOLT_DUTY  = 14,
+       MODE_AMP_DUTY   = 15,
+       MODE_WIDTH      = 16,
+       MODE_VOLT_WIDTH = 17,
+       MODE_AMP_WIDTH  = 18,
+       MODE_DIODE      = 19,
+       MODE_CONT       = 20,
+       MODE_HFE        = 21,
+       MODE_LOGIC      = 22,
+       MODE_DBM        = 23,
+       // MODE_EF      = 24,
+       MODE_TEMP       = 25,
+       MODE_INVALID    = 26,
+};
+
+enum {
+       READ_ALL,
+       READ_TEMP,
+};
 
-static gboolean rs_22_812_is_checksum_valid(const rs_22_812_packet *data)
+static gboolean checksum_valid(const struct rs_22_812_packet *rs_packet)
 {
-       uint8_t *raw = (void *) data;
+       uint8_t *raw;
        uint8_t sum = 0;
-       size_t i;
-       for(i = 0; i < RS_22_812_PACKET_SIZE - 1; i++)
+       int i;
+
+       raw = (void *)rs_packet;
+
+       for (i = 0; i < RS_22_812_PACKET_SIZE - 1; i++)
                sum += raw[i];
-       /* This is just a funky constant added to the checksum */
+
+       /* This is just a funky constant added to the checksum. */
        sum += 57;
-       sum -= data->checksum;
-       return(sum == 0);
+       sum -= rs_packet->checksum;
+       return (sum == 0);
 }
 
-static gboolean rs_22_812_is_mode_valid(rs_22_812_mode mode)
+static gboolean selection_good(const struct rs_22_812_packet *rs_packet)
 {
-       return(mode < RS_22_812_MODE_INVALID);
-}
+       int count;
 
-static gboolean rs_22_812_is_selection_good(const rs_22_812_packet *data)
-{
-       int n_postfix = 0;
-       int n_type = 0;
        /* Does the packet have more than one multiplier ? */
-       if(data->indicatrix1 & RS_22_812_IND1_KILO)
-               n_postfix++;
-       if(data->indicatrix1 & RS_22_812_IND1_MEGA)
-               n_postfix++;
-       if(data->indicatrix1 & RS_22_812_IND1_MILI)
-               n_postfix++;
-       if(data->indicatrix2 & RS_22_812_IND2_MICRO)
-               n_postfix++;
-       if(data->indicatrix2 & RS_22_812_IND2_NANO)
-               n_postfix++;
-       if(n_postfix > 1)
+       count = 0;
+       count += (rs_packet->indicatrix1 & IND1_KILO)  ? 1 : 0;
+       count += (rs_packet->indicatrix1 & IND1_MEGA)  ? 1 : 0;
+       count += (rs_packet->indicatrix1 & IND1_MILI)  ? 1 : 0;
+       count += (rs_packet->indicatrix2 & IND2_MICRO) ? 1 : 0;
+       count += (rs_packet->indicatrix2 & IND2_NANO)  ? 1 : 0;
+       if (count > 1) {
+               sr_err("More than one multiplier detected in packet.");
                return FALSE;
+       }
 
-       /* Does the packet "measure" more than one type of value ?*/
-       if(data->indicatrix1 & RS_22_812_IND1_HZ)
-               n_type++;
-       if(data->indicatrix1 & RS_22_812_IND1_OHM)
-               n_type++;
-       if(data->indicatrix1 & RS_22_812_IND1_FARAD)
-               n_type++;
-       if(data->indicatrix1 & RS_22_812_IND1_AMP)
-               n_type++;
-       if(data->indicatrix1 & RS_22_812_IND1_VOLT)
-               n_type++;
-       if(data->indicatrix2 & RS_22_812_IND2_DBM)
-               n_type++;
-       if(data->indicatrix2 & RS_22_812_IND2_SEC)
-               n_type++;
-       if(data->indicatrix2 & RS_22_812_IND2_DUTY)
-               n_type++;
-       if(data->indicatrix2 & RS_22_812_IND2_HFE)
-               n_type++;
-       if(n_type > 1)
+       /* Does the packet "measure" more than one type of value? */
+       count = 0;
+       count += (rs_packet->indicatrix1 & IND1_HZ)    ? 1 : 0;
+       count += (rs_packet->indicatrix1 & IND1_OHM)   ? 1 : 0;
+       count += (rs_packet->indicatrix1 & IND1_FARAD) ? 1 : 0;
+       count += (rs_packet->indicatrix1 & IND1_AMP)   ? 1 : 0;
+       count += (rs_packet->indicatrix1 & IND1_VOLT)  ? 1 : 0;
+       count += (rs_packet->indicatrix2 & IND2_DBM)   ? 1 : 0;
+       count += (rs_packet->indicatrix2 & IND2_SEC)   ? 1 : 0;
+       count += (rs_packet->indicatrix2 & IND2_DUTY)  ? 1 : 0;
+       count += (rs_packet->indicatrix2 & IND2_HFE)   ? 1 : 0;
+       if (count > 1) {
+               sr_err("More than one measurement type detected in packet.");
                return FALSE;
+       }
 
-       /* OK, no duplicates */
        return TRUE;
 }
 
-/* Since the RS 22-812 does not identify itslef in any way shape, or form,
+/*
+ * Since the 22-812 does not identify itself in any way, shape, or form,
  * we really don't know for sure who is sending the data. We must use every
  * possible check to filter out bad packets, especially since detection of the
- * 22-812 depends on how well we can filter the packets */
-SR_PRIV gboolean rs_22_812_is_packet_valid(const rs_22_812_packet *packet)
+ * 22-812 depends on how well we can filter the packets.
+ */
+SR_PRIV gboolean rs_22_812_packet_valid(const struct rs_22_812_packet *rs_packet)
 {
-       /* Unfortunately, the packet doesn't have a signature, so we must
-        * compute its checksum first */
-       if(!rs_22_812_is_checksum_valid(packet))
+       if (!checksum_valid(rs_packet))
                return FALSE;
 
-       if(!rs_22_812_is_mode_valid(packet->mode))
+       if (!(rs_packet->mode < MODE_INVALID))
                return FALSE;
 
-       if(!rs_22_812_is_selection_good(packet)) {
+       if (!selection_good(rs_packet))
                return FALSE;
-       }
-       /* Made it here, huh? Then this looks to be a valid packet */
+
        return TRUE;
 }
 
-static uint8_t rs_22_812_to_digit(uint8_t raw_digit)
+static uint8_t decode_digit(uint8_t raw_digit)
 {
-       /* Take out the decimal point, so we can use a simple switch() */
-       raw_digit &= ~RS_22_812_DP_MASK;
-       switch(raw_digit)
-       {
+       /* Take out the decimal point, so we can use a simple switch(). */
+       raw_digit &= ~DP_MASK;
+
+       switch (raw_digit) {
        case 0x00:
-       case RS_22_812_LCD_0:
+       case LCD_0:
                return 0;
-       case RS_22_812_LCD_1:
+       case LCD_1:
                return 1;
-       case RS_22_812_LCD_2:
+       case LCD_2:
                return 2;
-       case RS_22_812_LCD_3:
+       case LCD_3:
                return 3;
-       case RS_22_812_LCD_4:
+       case LCD_4:
                return 4;
-       case RS_22_812_LCD_5:
+       case LCD_5:
                return 5;
-       case RS_22_812_LCD_6:
+       case LCD_6:
                return 6;
-       case RS_22_812_LCD_7:
+       case LCD_7:
                return 7;
-       case RS_22_812_LCD_8:
+       case LCD_8:
                return 8;
-       case RS_22_812_LCD_9:
+       case LCD_9:
                return 9;
        default:
+               sr_err("Invalid digit byte: 0x%02x.", raw_digit);
                return 0xff;
        }
 }
 
-typedef enum {
-       READ_ALL,
-       READ_TEMP,
-} value_type;
-
-static double lcdraw_to_double(rs_22_812_packet *rs_packet, value_type type)
+static double lcd_to_double(const struct rs_22_812_packet *rs_packet, int type)
 {
-       /* *********************************************************************
-        * Get a raw floating point value from the data
-        **********************************************************************/
-       double rawval;
-       double multiplier = 1;
-       uint8_t digit;
+       double rawval, multiplier = 1;
+       uint8_t digit, raw_digit;
        gboolean dp_reached = FALSE;
        int i, end;
-       switch(type) {
-       case READ_TEMP:
-               /* Do not parse the last digit */
-               end = 1;
-               break;
-       case READ_ALL:
-       default:
-               /* Parse all digits */
-               end = 0;
-       }
-       /* We have 4 digits, and we start from the most significant */
-       for(i = 3; i >= end; i--)
-       {
-               uint8_t raw_digit = *(&(rs_packet->digit4) + i);
-               digit = rs_22_812_to_digit(raw_digit);
-               if(digit == 0xff) {
+
+       /* end = 1: Don't parse last digit. end = 0: Parse all digits. */
+       end = (type == READ_TEMP) ? 1 : 0;
+
+       /* We have 4 digits, and we start from the most significant. */
+       for (i = 3; i >= end; i--) {
+               raw_digit = *(&(rs_packet->digit4) + i);
+               digit = decode_digit(raw_digit);
+               if (digit == 0xff) {
                        rawval = NAN;
                        break;
                }
-               /* Digit 1 does not have a decimal point. Instead, the decimal
-                * point is used to indicate MAX, so we must avoid testing it */
-               if( (i < 3) && (raw_digit & RS_22_812_DP_MASK) )
+               /*
+                * Digit 1 does not have a decimal point. Instead, the decimal
+                * point is used to indicate MAX, so we must avoid testing it.
+                */
+               if ((i < 3) && (raw_digit & DP_MASK))
                        dp_reached = TRUE;
-               if(dp_reached) multiplier /= 10;
+               if (dp_reached)
+                       multiplier /= 10;
                rawval = rawval * 10 + digit;
        }
        rawval *= multiplier;
-       if(rs_packet->info & RS_22_812_INFO_NEG)
+       if (rs_packet->info & INFO_NEG)
                rawval *= -1;
 
-       /* See if we need to multiply our raw value by anything */
-       if(rs_packet->indicatrix1 & RS_22_812_IND2_NANO) {
+       /* See if we need to multiply our raw value by anything. */
+       if (rs_packet->indicatrix1 & IND2_NANO) {
                rawval *= 1E-9;
-       } else if(rs_packet->indicatrix2 & RS_22_812_IND2_MICRO) {
+       } else if (rs_packet->indicatrix2 & IND2_MICRO) {
                rawval *= 1E-6;
-       } else if(rs_packet->indicatrix1 & RS_22_812_IND1_MILI) {
+       } else if (rs_packet->indicatrix1 & IND1_MILI) {
                rawval *= 1E-3;
-       } else if(rs_packet->indicatrix1 & RS_22_812_IND1_KILO) {
+       } else if (rs_packet->indicatrix1 & IND1_KILO) {
                rawval *= 1E3;
-       } else if(rs_packet->indicatrix1 & RS_22_812_IND1_MEGA) {
+       } else if (rs_packet->indicatrix1 & IND1_MEGA) {
                rawval *= 1E6;
        }
 
        return rawval;
 }
 
-static gboolean rs_22_812_is_celsius(rs_22_812_packet *rs_packet)
+static gboolean is_celsius(struct rs_22_812_packet *rs_packet)
+{
+       return ((rs_packet->digit4 & ~DP_MASK) == LCD_C);
+}
+
+static gboolean is_shortcirc(struct rs_22_812_packet *rs_packet)
 {
-       return((rs_packet->digit4 & ~RS_22_812_DP_MASK) == RS_22_812_LCD_C);
+       return ((rs_packet->digit2 & ~DP_MASK) == LCD_h);
 }
 
-static gboolean rs_22_812_is_shortcirc(rs_22_812_packet *rs_packet)
+static gboolean is_logic_high(struct rs_22_812_packet *rs_packet)
 {
-       return((rs_packet->digit2 & ~RS_22_812_DP_MASK) == RS_22_812_LCD_h);
+       sr_spew("Digit 2: 0x%02x.", rs_packet->digit2 & ~DP_MASK);
+       return ((rs_packet->digit2 & ~DP_MASK) == LCD_H);
 }
 
-static void rs_22_812_handle_packet(rs_22_812_packet *rs_packet,
-                                   rs_dev_ctx *devc)
+static void handle_packet(struct rs_22_812_packet *rs_packet,
+                         struct dev_context *devc)
 {
-       double rawval = lcdraw_to_double(rs_packet, READ_ALL);
-       /* *********************************************************************
-        * Now see what the value means, and pass that on
-        **********************************************************************/
+       double rawval;
        struct sr_datafeed_packet packet;
        struct sr_datafeed_analog *analog;
 
+       rawval = lcd_to_double(rs_packet, READ_ALL);
+
+       /* TODO: Check malloc return value. */
        analog = g_try_malloc0(sizeof(struct sr_datafeed_analog));
        analog->num_samples = 1;
+       /* TODO: Check malloc return value. */
        analog->data = g_try_malloc(sizeof(float));
        *analog->data = (float)rawval;
        analog->mq = -1;
 
-       switch(rs_packet->mode) {
-       case RS_22_812_MODE_DC_V:
+       switch (rs_packet->mode) {
+       case MODE_DC_V:
                analog->mq = SR_MQ_VOLTAGE;
                analog->unit = SR_UNIT_VOLT;
                analog->mqflags |= SR_MQFLAG_DC;
                break;
-       case RS_22_812_MODE_AC_V:
+       case MODE_AC_V:
                analog->mq = SR_MQ_VOLTAGE;
                analog->unit = SR_UNIT_VOLT;
                analog->mqflags |= SR_MQFLAG_AC;
                break;
-       case RS_22_812_MODE_DC_UA:
-       case RS_22_812_MODE_DC_MA:
-       case RS_22_812_MODE_DC_A:
+       case MODE_DC_UA:
+       case MODE_DC_MA:
+       case MODE_DC_A:
                analog->mq = SR_MQ_CURRENT;
                analog->unit = SR_UNIT_AMPERE;
                analog->mqflags |= SR_MQFLAG_DC;
                break;
-       case RS_22_812_MODE_AC_UA:
-       case RS_22_812_MODE_AC_MA:
-       case RS_22_812_MODE_AC_A:
+       case MODE_AC_UA:
+       case MODE_AC_MA:
+       case MODE_AC_A:
                analog->mq = SR_MQ_CURRENT;
                analog->unit = SR_UNIT_AMPERE;
                analog->mqflags |= SR_MQFLAG_AC;
                break;
-       case RS_22_812_MODE_OHM:
+       case MODE_OHM:
                analog->mq = SR_MQ_RESISTANCE;
                analog->unit = SR_UNIT_OHM;
                break;
-       case RS_22_812_MODE_FARAD:
+       case MODE_FARAD:
                analog->mq = SR_MQ_CAPACITANCE;
                analog->unit = SR_UNIT_FARAD;
                break;
-       case RS_22_812_MODE_CONT:
+       case MODE_CONT:
                analog->mq = SR_MQ_CONTINUITY;
                analog->unit = SR_UNIT_BOOLEAN;
-               *analog->data = rs_22_812_is_shortcirc(rs_packet);
+               *analog->data = is_shortcirc(rs_packet);
                break;
-       case RS_22_812_MODE_DIODE:
+       case MODE_DIODE:
                analog->mq = SR_MQ_VOLTAGE;
                analog->unit = SR_UNIT_VOLT;
                analog->mqflags |= SR_MQFLAG_DIODE | SR_MQFLAG_DC;
                break;
-       case RS_22_812_MODE_HZ:
-       case RS_22_812_MODE_VOLT_HZ:
-       case RS_22_812_MODE_AMP_HZ:
+       case MODE_HZ:
+       case MODE_VOLT_HZ:
+       case MODE_AMP_HZ:
                analog->mq = SR_MQ_FREQUENCY;
                analog->unit = SR_UNIT_HERTZ;
                break;
-       case RS_22_812_MODE_LOGIC:
-               analog->mq = 0; /* FIXME */
-               analog->unit = SR_UNIT_BOOLEAN;
-               sr_warn("radioshack-dmm: LOGIC mode not supported yet");
-               g_free(analog->data);
-               g_free(analog);
-               return;
+       case MODE_LOGIC:
+               /*
+                * No matter whether or not we have an actual voltage reading,
+                * we are measuring voltage, so we set our MQ as VOLTAGE.
+                */
+               analog->mq = SR_MQ_VOLTAGE;
+               if (!isnan(rawval)) {
+                       /* We have an actual voltage. */
+                       analog->unit = SR_UNIT_VOLT;
+               } else {
+                       /* We have either HI or LOW. */
+                       analog->unit = SR_UNIT_BOOLEAN;
+                       *analog->data = is_logic_high(rs_packet);
+               }
                break;
-       case RS_22_812_MODE_HFE:
+       case MODE_HFE:
                analog->mq = SR_MQ_GAIN;
                analog->unit = SR_UNIT_UNITLESS;
                break;
-       case RS_22_812_MODE_DUTY:
-       case RS_22_812_MODE_VOLT_DUTY:
-       case RS_22_812_MODE_AMP_DUTY:
+       case MODE_DUTY:
+       case MODE_VOLT_DUTY:
+       case MODE_AMP_DUTY:
                analog->mq = SR_MQ_DUTY_CYCLE;
                analog->unit = SR_UNIT_PERCENTAGE;
                break;
-       case RS_22_812_MODE_WIDTH:
-       case RS_22_812_MODE_VOLT_WIDTH:
-       case RS_22_812_MODE_AMP_WIDTH:
+       case MODE_WIDTH:
+       case MODE_VOLT_WIDTH:
+       case MODE_AMP_WIDTH:
                analog->mq = SR_MQ_PULSE_WIDTH;
                analog->unit = SR_UNIT_SECOND;
-       case RS_22_812_MODE_TEMP:
+       case MODE_TEMP:
                analog->mq = SR_MQ_TEMPERATURE;
-               /* We need to reparse */
-               *analog->data = lcdraw_to_double(rs_packet, READ_TEMP);
-               analog->unit = rs_22_812_is_celsius(rs_packet)?
-                               SR_UNIT_CELSIUS:SR_UNIT_FAHRENHEIT;
+               /* We need to reparse. */
+               *analog->data = lcd_to_double(rs_packet, READ_TEMP);
+               analog->unit = is_celsius(rs_packet) ?
+                              SR_UNIT_CELSIUS : SR_UNIT_FAHRENHEIT;
                break;
-       case RS_22_812_MODE_DBM:
+       case MODE_DBM:
                analog->mq = SR_MQ_POWER;
                analog->unit = SR_UNIT_DECIBEL_MW;
                analog->mqflags |= SR_MQFLAG_AC;
                break;
        default:
-               sr_warn("radioshack-dmm: unkown mode: %d", rs_packet->mode);
+               sr_err("Unknown mode: %d.", rs_packet->mode);
                break;
        }
 
-       if(rs_packet->info & RS_22_812_INFO_HOLD) {
+       if (rs_packet->info & INFO_HOLD)
                analog->mqflags |= SR_MQFLAG_HOLD;
-       }
-       if(rs_packet->digit4 & RS_22_812_DIG4_MAX) {
+       if (rs_packet->digit4 & DIG4_MAX)
                analog->mqflags |= SR_MQFLAG_MAX;
-       }
-       if(rs_packet->indicatrix2 & RS_22_812_IND2_MIN) {
+       if (rs_packet->indicatrix2 & IND2_MIN)
                analog->mqflags |= SR_MQFLAG_MIN;
-       }
-       if(rs_packet->info & RS_22_812_INFO_AUTO) {
+       if (rs_packet->info & INFO_AUTO)
                analog->mqflags |= SR_MQFLAG_AUTORANGE;
-       }
 
        if (analog->mq != -1) {
                /* Got a measurement. */
-               sr_spew("radioshack-dmm: val %f", rawval);
+               sr_spew("Value: %f.", rawval);
                packet.type = SR_DF_ANALOG;
                packet.payload = analog;
                sr_session_send(devc->cb_data, &packet);
@@ -345,42 +419,41 @@ static void rs_22_812_handle_packet(rs_22_812_packet *rs_packet,
        g_free(analog);
 }
 
-static void handle_new_data(rs_dev_ctx *devc, int fd)
+static void handle_new_data(struct dev_context *devc, int fd)
 {
        int len;
-       size_t i;
-       size_t offset = 0;
-       /* Try to get as much data as the buffer can hold */
+       size_t i, offset = 0;
+       struct rs_22_812_packet *rs_packet;
+
+       /* Try to get as much data as the buffer can hold. */
        len = RS_DMM_BUFSIZE - devc->buflen;
        len = serial_read(fd, devc->buf + devc->buflen, len);
        if (len < 1) {
-               sr_err("radioshack-dmm: serial port read error!");
+               sr_err("Serial port read error.");
                return;
        }
        devc->buflen += len;
 
-       /* Now look for packets in that data */
-       while((devc->buflen - offset) >= RS_22_812_PACKET_SIZE)
-       {
-               rs_22_812_packet * packet = (void *)(devc->buf + offset);
-               if( rs_22_812_is_packet_valid(packet) )
-               {
-                       rs_22_812_handle_packet(packet, devc);
+       /* Now look for packets in that data. */
+       while ((devc->buflen - offset) >= RS_22_812_PACKET_SIZE) {
+               rs_packet = (void *)(devc->buf + offset);
+               if (rs_22_812_packet_valid(rs_packet)) {
+                       handle_packet(rs_packet, devc);
                        offset += RS_22_812_PACKET_SIZE;
                } else {
                        offset++;
                }
        }
 
-       /* If we have any data left, move it to the beginning of our buffer */
-       for(i = 0; i < devc->buflen - offset; i++)
+       /* If we have any data left, move it to the beginning of our buffer. */
+       for (i = 0; i < devc->buflen - offset; i++)
                devc->buf[i] = devc->buf[offset + i];
        devc->buflen -= offset;
 }
 
-SR_PRIV int radioshack_receive_data(int fd, int revents, void *cb_data)
+SR_PRIV int radioshack_dmm_receive_data(int fd, int revents, void *cb_data)
 {
-       const struct sr_dev_inst *sdi;
+       struct sr_dev_inst *sdi;
        struct dev_context *devc;
 
        if (!(sdi = cb_data))
@@ -389,8 +462,7 @@ SR_PRIV int radioshack_receive_data(int fd, int revents, void *cb_data)
        if (!(devc = sdi->priv))
                return TRUE;
 
-       if (revents == G_IO_IN)
-       {
+       if (revents == G_IO_IN) {
                /* Serial data arrived. */
                handle_new_data(devc, fd);
        }
@@ -402,5 +474,3 @@ SR_PRIV int radioshack_receive_data(int fd, int revents, void *cb_data)
 
        return TRUE;
 }
-
-