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Subject[PATCH 2/2] iio: adc: meson-saradc: enable the temperature sensor two more SoCs
Date
Meson8b and Meson8m2 use the same logic to convert the ADC register
value to celsius, which is different from Meson8:
- Meson8 has different multiplier and divider values
- Meson8 uses a 4-bit TSC (temperature sensor coefficient) which fits
into the 4-bit field in the MESON_SAR_ADC_DELTA_10 register:
MESON_SAR_ADC_DELTA_10_TS_C_MASK. Meson8b and Meson8m2 have a 5-bit
TSC which requires writing the upper-most bit into the
MESON_HHI_DPLL_TOP_0[9] register from the HHI register area.

This adds support for the temperature sensor on the Meson8b and Meson8m2
SoCs by implementing the logic to write the upper-most TSC bit into the
HHI register area. The SoC-specific values (temperature_trimming_bits,
temperature_multiplier, temperature_divider) are added - these simply
integrate into the existing infrastructure (which was implemented for
Meson8) and thus require no further changes to the existing temperature
calculation logic.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
drivers/iio/adc/meson_saradc.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 729becb2d3d9..f8600fbcdfe3 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -26,6 +26,7 @@
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
+#include <linux/mfd/syscon.h>

#define MESON_SAR_ADC_REG0 0x00
#define MESON_SAR_ADC_REG0_PANEL_DETECT BIT(31)
@@ -174,6 +175,9 @@
#define MESON_SAR_ADC_EFUSE_BYTE3_UPPER_ADC_VAL GENMASK(6, 0)
#define MESON_SAR_ADC_EFUSE_BYTE3_IS_CALIBRATED BIT(7)

+#define MESON_HHI_DPLL_TOP_0 0x318
+#define MESON_HHI_DPLL_TOP_0_TSC_BIT4 BIT(9)
+
/* for use with IIO_VAL_INT_PLUS_MICRO */
#define MILLION 1000000

@@ -280,6 +284,7 @@ struct meson_sar_adc_priv {
struct completion done;
int calibbias;
int calibscale;
+ struct regmap *tsc_regmap;
bool temperature_sensor_calibrated;
u8 temperature_sensor_coefficient;
u16 temperature_sensor_adc_val;
@@ -727,6 +732,15 @@ static int meson_sar_adc_temp_sensor_init(struct iio_dev *indio_dev)
return ret;
}

+ priv->tsc_regmap =
+ syscon_regmap_lookup_by_phandle(indio_dev->dev.parent->of_node,
+ "amlogic,hhi-sysctrl");
+ if (IS_ERR(priv->tsc_regmap)) {
+ dev_err(indio_dev->dev.parent,
+ "failed to get amlogic,hhi-sysctrl regmap\n");
+ return PTR_ERR(priv->tsc_regmap);
+ }
+
read_len = MESON_SAR_ADC_EFUSE_BYTES;
buf = nvmem_cell_read(temperature_calib, &read_len);
if (IS_ERR(buf)) {
@@ -861,6 +875,22 @@ static int meson_sar_adc_init(struct iio_dev *indio_dev)
priv->temperature_sensor_coefficient);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELTA_10,
MESON_SAR_ADC_DELTA_10_TS_C_MASK, regval);
+
+ if (priv->param->temperature_trimming_bits == 5) {
+ if (priv->temperature_sensor_coefficient & BIT(4))
+ regval = MESON_HHI_DPLL_TOP_0_TSC_BIT4;
+ else
+ regval = 0;
+
+ /*
+ * bit [4] (the 5th bit when starting to count at 1)
+ * of the TSC is located in the HHI register area.
+ */
+ regmap_update_bits(priv->tsc_regmap,
+ MESON_HHI_DPLL_TOP_0,
+ MESON_HHI_DPLL_TOP_0_TSC_BIT4,
+ regval);
+ }
} else {
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELTA_10,
MESON_SAR_ADC_DELTA_10_TS_REVE1, 0);
@@ -1064,6 +1094,9 @@ static const struct meson_sar_adc_param meson_sar_adc_meson8b_param = {
.bandgap_reg = MESON_SAR_ADC_DELTA_10,
.regmap_config = &meson_sar_adc_regmap_config_meson8,
.resolution = 10,
+ .temperature_trimming_bits = 5,
+ .temperature_multiplier = 10,
+ .temperature_divider = 32,
};

static const struct meson_sar_adc_param meson_sar_adc_gxbb_param = {
--
2.20.1
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