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From: Baolin Wang <baolin.wang@linaro.org>
To: sre@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com
Cc: linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, yuanjiang.yu@unisoc.com,
	baolin.wang@linaro.org, baolin.wang7@gmail.com,
	zhang.lyra@gmail.com, orsonzhai@gmail.com
Subject: [PATCH 5/5] power: supply: sc27xx: Calibrate the resistance of coulomb counter
Date: Mon, 28 Oct 2019 15:19:01 +0800	[thread overview]
Message-ID: <9c25e3ab9bdba2914b22cfe7495818740437ef27.1572245011.git.baolin.wang@linaro.org> (raw)
In-Reply-To: <cover.1572245011.git.baolin.wang@linaro.org>
In-Reply-To: <cover.1572245011.git.baolin.wang@linaro.org>

There are some deviations between the real resistance and the ideal
resistance of coulomb counter, which will affect the accuracy of
the coulomb counter, thus calibrate the real resistance of coulomb
counter to improve the accuracy.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 drivers/power/supply/sc27xx_fuel_gauge.c |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/sc27xx_fuel_gauge.c b/drivers/power/supply/sc27xx_fuel_gauge.c
index 221b6fb..f363fa7 100644
--- a/drivers/power/supply/sc27xx_fuel_gauge.c
+++ b/drivers/power/supply/sc27xx_fuel_gauge.c
@@ -62,6 +62,8 @@
 
 #define SC27XX_FGU_CUR_BASIC_ADC	8192
 #define SC27XX_FGU_SAMPLE_HZ		2
+/* micro Ohms */
+#define SC27XX_FGU_IDEAL_RESISTANCE	20000
 
 /*
  * struct sc27xx_fgu_data: describe the FGU device
@@ -84,6 +86,7 @@
  * @resist_table_len: the resistance table length
  * @cur_1000ma_adc: ADC value corresponding to 1000 mA
  * @vol_1000mv_adc: ADC value corresponding to 1000 mV
+ * @calib_resist: the real resistance of coulomb counter chip in mOhm
  * @cap_table: capacity table with corresponding ocv
  * @resist_table: resistance percent table with corresponding temperature
  */
@@ -108,6 +111,7 @@ struct sc27xx_fgu_data {
 	int resist_table_len;
 	int cur_1000ma_adc;
 	int vol_1000mv_adc;
+	int calib_resist;
 	struct power_supply_battery_ocv_table *cap_table;
 	struct power_supply_resistance_temp_table *resist_table;
 };
@@ -900,7 +904,9 @@ static int sc27xx_fgu_calibration(struct sc27xx_fgu_data *data)
 	 */
 	cal_4200mv = (calib_data & 0x1ff) + 6963 - 4096 - 256;
 	data->vol_1000mv_adc = DIV_ROUND_CLOSEST(cal_4200mv * 10, 42);
-	data->cur_1000ma_adc = data->vol_1000mv_adc * 4;
+	data->cur_1000ma_adc =
+		DIV_ROUND_CLOSEST(data->vol_1000mv_adc * 4 * data->calib_resist,
+				  SC27XX_FGU_IDEAL_RESISTANCE);
 
 	kfree(buf);
 	return 0;
@@ -1079,6 +1085,15 @@ static int sc27xx_fgu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = device_property_read_u32(&pdev->dev,
+				       "sprd,calib-resistance",
+				       &data->calib_resist);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to get fgu calibration resistance\n");
+		return ret;
+	}
+
 	data->channel = devm_iio_channel_get(dev, "bat-temp");
 	if (IS_ERR(data->channel)) {
 		dev_err(dev, "failed to get IIO channel\n");
-- 
1.7.9.5


      parent reply	other threads:[~2019-10-28  7:20 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-28  7:18 [PATCH 0/5] Improve the SC27XX fuel gauge controller Baolin Wang
2019-10-28  7:18 ` [PATCH 1/5] dt-bindings: power: Introduce one property to describe the battery resistance with temperature changes Baolin Wang
2019-10-30 14:38   ` Rob Herring
2019-10-31  2:13     ` Baolin Wang
2019-10-28  7:18 ` [PATCH 2/5] power: supply: core: Add battery internal resistance temperature table support Baolin Wang
2019-10-28  7:18 ` [PATCH 3/5] power: supply: sc27xx: Optimize the battery resistance with measuring temperature Baolin Wang
2019-10-28  7:19 ` [PATCH 4/5] dt-bindings: power: sc27xx: Add a new property to describe the real resistance of coulomb counter chip Baolin Wang
2019-10-30 14:39   ` Rob Herring
2019-10-31  2:14     ` Baolin Wang
2019-10-28  7:19 ` Baolin Wang [this message]

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