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From:   Claudiu Beznea <claudiu.beznea@microchip.com>
To:     <eugen.hristev@microchip.com>, <jic23@kernel.org>,
        <lars@metafoo.de>, <nicolas.ferre@microchip.com>,
        <alexandre.belloni@bootlin.com>, <ludovic.desroches@microchip.com>,
        <robh+dt@kernel.org>
CC:     <linux-iio@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        Claudiu Beznea <claudiu.beznea@microchip.com>
Subject: [PATCH v3 13/19] iio: adc: at91-sama5d2_adc: update trackx on emr
Date:   Wed, 3 Aug 2022 13:28:49 +0300
Message-ID: <20220803102855.2191070-14-claudiu.beznea@microchip.com>
In-Reply-To: <20220803102855.2191070-1-claudiu.beznea@microchip.com>
References: <20220803102855.2191070-1-claudiu.beznea@microchip.com>
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Add support for updating trackx bits of EMR register. Having different
values of EMR.TRACKX when measuring temperature give a better accuracy.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/iio/adc/at91-sama5d2_adc.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index a1df475a6f29..0209353cbfd7 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -145,6 +145,10 @@ struct at91_adc_reg_layout {
 #define AT91_SAMA5D2_EMR_OSR_64SAMPLES		3
 #define AT91_SAMA5D2_EMR_OSR_256SAMPLES		4
 
+/* Extended Mode Register - TRACKX */
+#define AT91_SAMA5D2_TRACKX_MASK		GENMASK(23, 22)
+#define AT91_SAMA5D2_TRACKX(x)			(((x) << 22) & \
+						 AT91_SAMA5D2_TRACKX_MASK)
 /* Extended Mode Register - Averaging on single trigger event */
 #define AT91_SAMA5D2_EMR_ASTE(V)		((V) << 20)
 
@@ -746,7 +750,7 @@ static void at91_adc_eoc_ena(struct at91_adc_state *st, unsigned int channel)
 }
 
 static int at91_adc_config_emr(struct at91_adc_state *st,
-			       u32 oversampling_ratio)
+			       u32 oversampling_ratio, u32 trackx)
 {
 	/* configure the extended mode register */
 	unsigned int emr = at91_adc_readl(st, EMR);
@@ -765,7 +769,7 @@ static int at91_adc_config_emr(struct at91_adc_state *st,
 	emr |= AT91_SAMA5D2_EMR_ASTE(1);
 
 	/* delete leftover content if it's the case */
-	emr &= ~osr_mask;
+	emr &= ~(osr_mask | AT91_SAMA5D2_TRACKX_MASK);
 
 	/* select oversampling ratio from configuration */
 	switch (oversampling_ratio) {
@@ -791,6 +795,8 @@ static int at91_adc_config_emr(struct at91_adc_state *st,
 		break;
 	}
 
+	/* Update trackx. */
+	emr |= AT91_SAMA5D2_TRACKX(trackx);
 	at91_adc_writel(st, EMR, emr);
 
 	st->oversampling_ratio = oversampling_ratio;
@@ -1706,7 +1712,7 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
 			return ret;
 		mutex_lock(&st->lock);
 		/* update ratio */
-		ret = at91_adc_config_emr(st, val);
+		ret = at91_adc_config_emr(st, val, 0);
 		mutex_unlock(&st->lock);
 		iio_device_release_direct_mode(indio_dev);
 		return ret;
@@ -1904,7 +1910,7 @@ static void at91_adc_hw_init(struct iio_dev *indio_dev)
 	at91_adc_setup_samp_freq(indio_dev, st->soc_info.min_sample_rate);
 
 	/* configure extended mode register */
-	at91_adc_config_emr(st, st->oversampling_ratio);
+	at91_adc_config_emr(st, st->oversampling_ratio, 0);
 }
 
 static ssize_t at91_adc_get_fifo_state(struct device *dev,
-- 
2.34.1