FS#9609 FM radio support for the Gigabeat S, seeking/scanning is not yet

implemented but manual tuning works nicely. Thanks to Rafaël Carré,
Bertrik Sikken and Robert Menes for suggestions and debugging help.



git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19372 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 146 insertions, 5 deletions

diff --git a/firmware/drivers/tuner/si4700.c b/firmware/drivers/tuner/si4700.c
index 9233afa..a55a8cf 100644
--- a/firmware/drivers/tuner/si4700.c
+++ b/firmware/drivers/tuner/si4700.c
@@ -9,7 +9,7 @@
  *
  * Tuner "middleware" for Silicon Labs SI4700 chip
  *
- * Copyright (C) 2008 ???
+ * Copyright (C) 2008 Nils Wallménius
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -29,19 +29,160 @@
 #include "fmradio.h"
 #include "fmradio_i2c.h" /* physical interface driver */
 
+#define I2C_ADR 0x20
+
+/* I2C writes start at register 02h so the first two bytes are
+   02h, next two 03h, etc. */
+static unsigned char write_bytes[8]; /* registers 02 - 05 */
+static bool tuner_present = false;
+
+void si4700_init(void)
+{
+    unsigned char read_bytes[32];
+    tuner_power(true);
+    fmradio_i2c_read(I2C_ADR, read_bytes, sizeof(read_bytes));
+
+    if ((read_bytes[12] << 8 | read_bytes[13]) == 0x1242)
+    {
+        tuner_present = true;
+        /* fill in the initial values in write_bytes */
+        memcpy(&write_bytes[0], &read_bytes[16], sizeof(write_bytes));
+        /* -6dB volume, keep everything else as default */
+        write_bytes[7] = (write_bytes[7] & ~0xf) | 0xc;
+    }
+
+    tuner_power(false);
+}
+
+static void si4700_tune(void)
+{
+    unsigned char read_bytes[1];
+
+    write_bytes[2] |= (1 << 7); /* Set TUNE high to start tuning */
+    fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
+
+    do
+    {
+        sleep(HZ/50);
+        fmradio_i2c_read(I2C_ADR, read_bytes, 1);
+    }
+    while (!(read_bytes[0] & (1 << 6))); /* STC high == Seek/Tune complete */
+
+    write_bytes[2] &= ~(1 << 7); /* Set TUNE low */
+    fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
+}
+
 /* tuner abstraction layer: set something to the tuner */
 int si4700_set(int setting, int value)
 {
-    (void)setting;
-    (void)value;
+    switch(setting)
+    {
+        case RADIO_SLEEP:
+            if (value)
+            {
+                write_bytes[1] = (1 | (1 << 6)); /* ENABLE high, DISABLE high */
+            }
+            else
+            {
+                write_bytes[1] = 1; /* ENABLE high, DISABLE low */
+            }
+            break;
 
+        case RADIO_FREQUENCY:
+        {
+            static const unsigned int spacings[3] =
+            {
+                200000, 100000, 50000
+            };
+            unsigned int chan;
+            unsigned int spacing = spacings[(write_bytes[7] >> 4) & 3] ;
+
+            if (write_bytes[7] & (3 << 6)) /* check BAND */
+            {
+                chan = (value - 76000000) / spacing;
+            }
+            else
+            {
+                chan = (value - 87500000) / spacing;
+            }
+
+            write_bytes[2] = (write_bytes[2] & ~3) | ((chan & (3 << 8)) >> 8);
+            write_bytes[3] = (chan & 0xff);
+            fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
+            si4700_tune();
+            return 1;
+        }
+
+        case RADIO_SCAN_FREQUENCY:
+            si4700_set(RADIO_FREQUENCY, value);
+            return 1;
+
+        case RADIO_MUTE:
+            if (value)
+            {
+                /* mute */
+                write_bytes[0] &= ~(1 << 6);
+            }
+            else
+            {
+                /* unmute */
+                write_bytes[0] |= (1 << 6);
+            }
+            break;
+
+        case RADIO_REGION:
+        {
+            const struct si4700_region_data *rd =
+                &si4700_region_data[value];
+
+            write_bytes[4] = ((write_bytes[4] & ~(1 << 3)) | (rd->deemphasis << 3));
+            write_bytes[7] = ((write_bytes[7] & ~(3 << 6)) | (rd->band << 6));
+            write_bytes[7] = ((write_bytes[7] & ~(3 << 4)) | (rd->spacing << 4));
+            break;
+        }
+
+        case RADIO_FORCE_MONO:
+            if (value)
+            {
+                write_bytes[0] |= (1 << 5);
+            }
+            else
+            {
+                write_bytes[0] &= ~(1 << 5);
+            }
+            break;
+
+        default:
+            return -1;
+    }
+
+    fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
     return 1;
 }
 
 /* tuner abstraction layer: read something from the tuner */
 int si4700_get(int setting)
 {
-    (void)setting;
+    /* I2C reads start with register 0xA */
+    unsigned char read_bytes[1];
+    int val = -1; /* default for unsupported query */
+
+    switch(setting)
+    {
+        case RADIO_PRESENT:
+            val = tuner_present ? 1 : 0;
+            break;
 
-    return -1;
+        case RADIO_TUNED:
+            val = 1;
+            break;
+
+        case RADIO_STEREO:
+            fmradio_i2c_read(I2C_ADR, read_bytes, sizeof(read_bytes));
+            val = (read_bytes[0] & 1); /* ST high == Stereo */
+            break;
+    }
+
+    return val;
 }
+