mfd: sc27xx: Add USB charger type detection support

The Spreadtrum SC27XX series PMICs supply the USB charger type detection
function, and related registers are located on the PMIC global registers
region, thus we implement and export this function in the MFD driver for
users to get the USB charger type.
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/sprd-sc27xx-spi.c

@@ -10,6 +10,7 @@
 #include <linux/of_device.h>
 #include <linux/regmap.h>
 #include <linux/spi/spi.h>
+#include <uapi/linux/usb/charger.h>
 
 #define SPRD_PMIC_INT_MASK_STATUS	0x0
 #define SPRD_PMIC_INT_RAW_STATUS	0x4
@@ -17,6 +18,16 @@
 
 #define SPRD_SC2731_IRQ_BASE		0x140
 #define SPRD_SC2731_IRQ_NUMS		16
+#define SPRD_SC2731_CHG_DET		0xedc
+
+/* PMIC charger detection definition */
+#define SPRD_PMIC_CHG_DET_DELAY_US	200000
+#define SPRD_PMIC_CHG_DET_TIMEOUT	2000000
+#define SPRD_PMIC_CHG_DET_DONE		BIT(11)
+#define SPRD_PMIC_SDP_TYPE		BIT(7)
+#define SPRD_PMIC_DCP_TYPE		BIT(6)
+#define SPRD_PMIC_CDP_TYPE		BIT(5)
+#define SPRD_PMIC_CHG_TYPE_MASK		GENMASK(7, 5)
 
 struct sprd_pmic {
 	struct regmap *regmap;
@@ -24,12 +35,14 @@ struct sprd_pmic {
 	struct regmap_irq *irqs;
 	struct regmap_irq_chip irq_chip;
 	struct regmap_irq_chip_data *irq_data;
+	const struct sprd_pmic_data *pdata;
 	int irq;
 };
 
 struct sprd_pmic_data {
 	u32 irq_base;
 	u32 num_irqs;
+	u32 charger_det;
 };
 
 /*
@@ -40,8 +53,46 @@ struct sprd_pmic_data {
 static const struct sprd_pmic_data sc2731_data = {
 	.irq_base = SPRD_SC2731_IRQ_BASE,
 	.num_irqs = SPRD_SC2731_IRQ_NUMS,
+	.charger_det = SPRD_SC2731_CHG_DET,
 };
 
+enum usb_charger_type sprd_pmic_detect_charger_type(struct device *dev)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct sprd_pmic *ddata = spi_get_drvdata(spi);
+	const struct sprd_pmic_data *pdata = ddata->pdata;
+	enum usb_charger_type type;
+	u32 val;
+	int ret;
+
+	ret = regmap_read_poll_timeout(ddata->regmap, pdata->charger_det, val,
+				       (val & SPRD_PMIC_CHG_DET_DONE),
+				       SPRD_PMIC_CHG_DET_DELAY_US,
+				       SPRD_PMIC_CHG_DET_TIMEOUT);
+	if (ret) {
+		dev_err(&spi->dev, "failed to detect charger type\n");
+		return UNKNOWN_TYPE;
+	}
+
+	switch (val & SPRD_PMIC_CHG_TYPE_MASK) {
+	case SPRD_PMIC_CDP_TYPE:
+		type = CDP_TYPE;
+		break;
+	case SPRD_PMIC_DCP_TYPE:
+		type = DCP_TYPE;
+		break;
+	case SPRD_PMIC_SDP_TYPE:
+		type = SDP_TYPE;
+		break;
+	default:
+		type = UNKNOWN_TYPE;
+		break;
+	}
+
+	return type;
+}
+EXPORT_SYMBOL_GPL(sprd_pmic_detect_charger_type);
+
 static const struct mfd_cell sprd_pmic_devs[] = {
 	{
 		.name = "sc27xx-wdt",
@@ -181,6 +232,7 @@ static int sprd_pmic_probe(struct spi_device *spi)
 	spi_set_drvdata(spi, ddata);
 	ddata->dev = &spi->dev;
 	ddata->irq = spi->irq;
+	ddata->pdata = pdata;
 
 	ddata->irq_chip.name = dev_name(&spi->dev);
 	ddata->irq_chip.status_base =

include/linux/mfd/sc27xx-pmic.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_MFD_SC27XX_PMIC_H
+#define __LINUX_MFD_SC27XX_PMIC_H
+
+extern enum usb_charger_type sprd_pmic_detect_charger_type(struct device *dev);
+
+#endif /* __LINUX_MFD_SC27XX_PMIC_H */