linux-kernel - [PATCH V2 4/5] iio/adc: ingenic: add JZ4760B support to the sadc driver

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Message-Id: <20210723085813.1523934-5-cbranchereau@gmail.com>
Date:   Fri, 23 Jul 2021 10:58:12 +0200
From:   Christophe Branchereau <cbranchereau@...il.com>
To:     paul@...pouillou.net
Cc:     jic23@...nel.org, lars@...afoo.de, linux-mips@...r.kernel.org,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        robh+dt@...nel.org, devicetree@...r.kernel.org, linux@...ck-us.net,
        contact@...ur-rojek.eu,
        Christophe Branchereau <cbranchereau@...il.com>
Subject: [PATCH V2 4/5] iio/adc: ingenic: add JZ4760B support to the sadc driver

The JZ4760B variant differs slightly from the JZ4760: it has a bit called 
VBAT_SEL in the CFG register.

In order to correctly sample the battery voltage on existing handhelds 
using this SOC, the bit must be cleared.

We leave the possibility to set the bit, by adding the 
"ingenic,use-internal-divider" property to a devicetree.

Signed-off-by: Christophe Branchereau <cbranchereau@...il.com>
---
 drivers/iio/adc/ingenic-adc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c
index 6b9af0530590..09937c05d2af 100644
--- a/drivers/iio/adc/ingenic-adc.c
+++ b/drivers/iio/adc/ingenic-adc.c
@@ -37,6 +37,7 @@
 #define JZ_ADC_REG_CFG_SAMPLE_NUM(n)	((n) << 10)
 #define JZ_ADC_REG_CFG_PULL_UP(n)	((n) << 16)
 #define JZ_ADC_REG_CFG_CMD_SEL		BIT(22)
+#define JZ_ADC_REG_CFG_VBAT_SEL		BIT(30)
 #define JZ_ADC_REG_CFG_TOUCH_OPS_MASK	(BIT(31) | GENMASK(23, 10))
 #define JZ_ADC_REG_ADCLK_CLKDIV_LSB	0
 #define JZ4725B_ADC_REG_ADCLK_CLKDIV10US_LSB	16
@@ -879,6 +880,12 @@ static int ingenic_adc_probe(struct platform_device *pdev)
 	/* Put hardware in a known passive state. */
 	writeb(0x00, adc->base + JZ_ADC_REG_ENABLE);
 	writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
+
+	if (device_property_present(dev, "ingenic,use-internal-divider")) /* JZ4760B specific */
+		ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_VBAT_SEL, JZ_ADC_REG_CFG_VBAT_SEL);
+	else
+		ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_VBAT_SEL, 0);
+
 	usleep_range(2000, 3000); /* Must wait at least 2ms. */
 	clk_disable(adc->clk);
 
@@ -906,6 +913,7 @@ static const struct of_device_id ingenic_adc_of_match[] = {
 	{ .compatible = "ingenic,jz4725b-adc", .data = &jz4725b_adc_soc_data, },
 	{ .compatible = "ingenic,jz4740-adc", .data = &jz4740_adc_soc_data, },
 	{ .compatible = "ingenic,jz4760-adc", .data = &jz4760_adc_soc_data, },
+	{ .compatible = "ingenic,jz4760b-adc", .data = &jz4760_adc_soc_data, },
 	{ .compatible = "ingenic,jz4770-adc", .data = &jz4770_adc_soc_data, },
 	{ },
 };
-- 
2.30.2