[media] tda10021: Don't use a magic numbers for QAM modulation (27d9a5e9) · Commits · 戴 / test

drivers/media/dvb/frontends/tda10021.c

+37 −22

Original line number	Diff line number	Diff line
		@@ -224,27 +224,43 @@ static int tda10021_init (struct dvb_frontend *fe)
		return 0;
		}

		struct qam_params {
		u8 conf, agcref, lthr, mseth, aref;
		};

		static int tda10021_set_parameters (struct dvb_frontend *fe,
		struct dvb_frontend_parameters *p)
		{
		struct tda10021_state* state = fe->demodulator_priv;

		//table for QAM4-QAM256 ready QAM4 QAM16 QAM32 QAM64 QAM128 QAM256
		//CONF
		static const u8 reg0x00 [] = { 0x14, 0x00, 0x04, 0x08, 0x0c, 0x10 };
		//AGCREF value
		static const u8 reg0x01 [] = { 0x78, 0x8c, 0x8c, 0x6a, 0x78, 0x5c };
		//LTHR value
		static const u8 reg0x05 [] = { 0x78, 0x87, 0x64, 0x46, 0x36, 0x26 };
		//MSETH
		static const u8 reg0x08 [] = { 0x8c, 0xa2, 0x74, 0x43, 0x34, 0x23 };
		//AREF
		static const u8 reg0x09 [] = { 0x96, 0x91, 0x96, 0x6a, 0x7e, 0x6b };

		static const struct qam_params qam_params[] = {
		/* Modulation Conf AGCref LTHR MSETH AREF */
		[QPSK] = { 0x14, 0x78, 0x78, 0x8c, 0x96 },
		[QAM_16] = { 0x00, 0x8c, 0x87, 0xa2, 0x91 },
		[QAM_32] = { 0x04, 0x8c, 0x64, 0x74, 0x96 },
		[QAM_64] = { 0x08, 0x6a, 0x46, 0x43, 0x6a },
		[QAM_128] = { 0x0c, 0x78, 0x36, 0x34, 0x7e },
		[QAM_256] = { 0x10, 0x5c, 0x26, 0x23, 0x6b },
		};
		int qam = p->u.qam.modulation;

		if (qam < 0 \|\| qam > 5)
		/*
		* gcc optimizes the code bellow the same way as it would code:
		* "if (qam > 5) return -EINVAL;"
		* Yet, the code is clearer, as it shows what QAM standards are
		* supported by the driver, and avoids the usage of magic numbers on
		* it.
		*/
		switch (qam) {
		case QPSK:
		case QAM_16:
		case QAM_32:
		case QAM_64:
		case QAM_128:
		case QAM_256:
		break;
		default:
		return -EINVAL;
		}

		if (p->inversion != INVERSION_ON && p->inversion != INVERSION_OFF)
		return -EINVAL;
		@@ -259,12 +275,11 @@ static int tda10021_set_parameters (struct dvb_frontend *fe,
		tda10021_set_symbolrate(state, p->u.qam.symbol_rate);
		_tda10021_writereg(state, 0x34, state->pwm);

		_tda10021_writereg (state, 0x01, reg0x01[qam]);
		_tda10021_writereg (state, 0x05, reg0x05[qam]);
		_tda10021_writereg (state, 0x08, reg0x08[qam]);
		_tda10021_writereg (state, 0x09, reg0x09[qam]);

		tda10021_setup_reg0 (state, reg0x00[qam], p->inversion);
		_tda10021_writereg(state, 0x01, qam_params[qam].agcref);
		_tda10021_writereg(state, 0x05, qam_params[qam].lthr);
		_tda10021_writereg(state, 0x08, qam_params[qam].mseth);
		_tda10021_writereg(state, 0x09, qam_params[qam].aref);
		tda10021_setup_reg0(state, qam_params[qam].conf, p->inversion);

		return 0;
		}

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