[media] drx-j: re-add get_sig_strength()

We'll need to use this function. Restore it from the
git history.

This function will be used on the next patch.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/drx39xyj/drxj.c b/drivers/media/dvb-frontends/drx39xyj/drxj.c
index 7022a69f56bd..ca807b1fc67c 100644
--- a/drivers/media/dvb-frontends/drx39xyj/drxj.c
+++ b/drivers/media/dvb-frontends/drx39xyj/drxj.c
@@ -9352,6 +9352,83 @@ rw_error:
 /*============================================================================*/
 
 /**
+ * \fn int get_sig_strength()
+ * \brief Retrieve signal strength for VSB and QAM.
+ * \param demod Pointer to demod instance
+ * \param u16-t Pointer to signal strength data; range 0, .. , 100.
+ * \return int.
+ * \retval 0 sig_strength contains valid data.
+ * \retval -EINVAL sig_strength is NULL.
+ * \retval -EIO Erroneous data, sig_strength contains invalid data.
+ */
+#define DRXJ_AGC_TOP    0x2800
+#define DRXJ_AGC_SNS    0x1600
+#define DRXJ_RFAGC_MAX  0x3fff
+#define DRXJ_RFAGC_MIN  0x800
+
+static int get_sig_strength(struct drx_demod_instance *demod, u16 *sig_strength)
+{
+        struct i2c_device_addr *dev_addr = demod->my_i2c_dev_addr;
+        int rc;
+        u16 rf_gain = 0;
+        u16 if_gain = 0;
+        u16 if_agc_sns = 0;
+        u16 if_agc_top = 0;
+        u16 rf_agc_max = 0;
+        u16 rf_agc_min = 0;
+
+        rc = drxj_dap_read_reg16(dev_addr, IQM_AF_AGC_IF__A, &if_gain, 0);
+        if (rc != 0) {
+                pr_err("error %d\n", rc);
+                goto rw_error;
+        }
+        if_gain &= IQM_AF_AGC_IF__M;
+        rc = drxj_dap_read_reg16(dev_addr, IQM_AF_AGC_RF__A, &rf_gain, 0);
+        if (rc != 0) {
+                pr_err("error %d\n", rc);
+                goto rw_error;
+        }
+        rf_gain &= IQM_AF_AGC_RF__M;
+
+        if_agc_sns = DRXJ_AGC_SNS;
+        if_agc_top = DRXJ_AGC_TOP;
+        rf_agc_max = DRXJ_RFAGC_MAX;
+        rf_agc_min = DRXJ_RFAGC_MIN;
+
+        if (if_gain > if_agc_top) {
+                if (rf_gain > rf_agc_max)
+                        *sig_strength = 100;
+                else if (rf_gain > rf_agc_min) {
+                        if (rf_agc_max == rf_agc_min) {
+                                pr_err("error: rf_agc_max == rf_agc_min\n");
+                                return -EIO;
+                        }
+                        *sig_strength =
+                        75 + 25 * (rf_gain - rf_agc_min) / (rf_agc_max -
+                                                                rf_agc_min);
+                } else
+                        *sig_strength = 75;
+        } else if (if_gain > if_agc_sns) {
+                if (if_agc_top == if_agc_sns) {
+                        pr_err("error: if_agc_top == if_agc_sns\n");
+                        return -EIO;
+                }
+                *sig_strength =
+                20 + 55 * (if_gain - if_agc_sns) / (if_agc_top - if_agc_sns);
+        } else {
+                if (!if_agc_sns) {
+                        pr_err("error: if_agc_sns is zero!\n");
+                        return -EIO;
+                }
+                *sig_strength = (20 * if_gain / if_agc_sns);
+        }
+
+        return 0;
+        rw_error:
+        return -EIO;
+}
+
+/**
 * \fn int ctrl_get_qam_sig_quality()
 * \brief Retreive QAM signal quality from device.
 * \param devmod Pointer to demodulator instance.