mfd: stmpe: Preparations for STMPE ADC driver

This prepares the MFD for the STMPE ADC driver. This commit introduces
devicetree settings that are used by the ADC and adds an init function.
Common ADC settings that are shared with the touchscreen driver can now
reside in the overlying MFD.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1204,7 +1204,7 @@ config MFD_STMPE
 
 	  Currently supported devices are:
 
-		STMPE811: GPIO, Touchscreen
+		STMPE811: GPIO, Touchscreen, ADC
 		STMPE1601: GPIO, Keypad
 		STMPE1801: GPIO, Keypad
 		STMPE2401: GPIO, Keypad
@@ -1217,6 +1217,7 @@ config MFD_STMPE
 		GPIO: stmpe-gpio
 		Keypad: stmpe-keypad
 		Touchscreen: stmpe-ts
+		ADC: stmpe-adc
 
 menu "STMicroelectronics STMPE Interface Drivers"
 depends on MFD_STMPE

drivers/mfd/stmpe.c

@@ -463,6 +463,28 @@ static const struct mfd_cell stmpe_ts_cell = {
 	.num_resources	= ARRAY_SIZE(stmpe_ts_resources),
 };
 
+/*
+ * ADC (STMPE811)
+ */
+
+static struct resource stmpe_adc_resources[] = {
+	{
+		.name	= "STMPE_TEMP_SENS",
+		.flags	= IORESOURCE_IRQ,
+	},
+	{
+		.name	= "STMPE_ADC",
+		.flags	= IORESOURCE_IRQ,
+	},
+};
+
+static const struct mfd_cell stmpe_adc_cell = {
+	.name		= "stmpe-adc",
+	.of_compatible	= "st,stmpe-adc",
+	.resources	= stmpe_adc_resources,
+	.num_resources	= ARRAY_SIZE(stmpe_adc_resources),
+};
+
 /*
  * STMPE811 or STMPE610
  */
@@ -497,6 +519,11 @@ static struct stmpe_variant_block stmpe811_blocks[] = {
 		.irq	= STMPE811_IRQ_TOUCH_DET,
 		.block	= STMPE_BLOCK_TOUCHSCREEN,
 	},
+	{
+		.cell	= &stmpe_adc_cell,
+		.irq	= STMPE811_IRQ_TEMP_SENS,
+		.block	= STMPE_BLOCK_ADC,
+	},
 };
 
 static int stmpe811_enable(struct stmpe *stmpe, unsigned int blocks,
@@ -517,6 +544,35 @@ static int stmpe811_enable(struct stmpe *stmpe, unsigned int blocks,
 				enable ? 0 : mask);
 }
 
+int stmpe811_adc_common_init(struct stmpe *stmpe)
+{
+	int ret;
+	u8 adc_ctrl1, adc_ctrl1_mask;
+
+	adc_ctrl1 = STMPE_SAMPLE_TIME(stmpe->sample_time) |
+		    STMPE_MOD_12B(stmpe->mod_12b) |
+		    STMPE_REF_SEL(stmpe->ref_sel);
+	adc_ctrl1_mask = STMPE_SAMPLE_TIME(0xff) | STMPE_MOD_12B(0xff) |
+			 STMPE_REF_SEL(0xff);
+
+	ret = stmpe_set_bits(stmpe, STMPE811_REG_ADC_CTRL1,
+			adc_ctrl1_mask, adc_ctrl1);
+	if (ret) {
+		dev_err(stmpe->dev, "Could not setup ADC\n");
+		return ret;
+	}
+
+	ret = stmpe_set_bits(stmpe, STMPE811_REG_ADC_CTRL2,
+			STMPE_ADC_FREQ(0xff), STMPE_ADC_FREQ(stmpe->adc_freq));
+	if (ret) {
+		dev_err(stmpe->dev, "Could not setup ADC\n");
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(stmpe811_adc_common_init);
+
 static int stmpe811_get_altfunc(struct stmpe *stmpe, enum stmpe_block block)
 {
 	/* 0 for touchscreen, 1 for GPIO */
@@ -1325,6 +1381,7 @@ int stmpe_probe(struct stmpe_client_info *ci, enum stmpe_partnum partnum)
 	struct device_node *np = ci->dev->of_node;
 	struct stmpe *stmpe;
 	int ret;
+	u32 val;
 
 	pdata = devm_kzalloc(ci->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
@@ -1342,6 +1399,15 @@ int stmpe_probe(struct stmpe_client_info *ci, enum stmpe_partnum partnum)
 	mutex_init(&stmpe->irq_lock);
 	mutex_init(&stmpe->lock);
 
+	if (!of_property_read_u32(np, "st,sample-time", &val))
+		stmpe->sample_time = val;
+	if (!of_property_read_u32(np, "st,mod-12b", &val))
+		stmpe->mod_12b = val;
+	if (!of_property_read_u32(np, "st,ref-sel", &val))
+		stmpe->ref_sel = val;
+	if (!of_property_read_u32(np, "st,adc-freq", &val))
+		stmpe->adc_freq = val;
+
 	stmpe->dev = ci->dev;
 	stmpe->client = ci->client;
 	stmpe->pdata = pdata;
@@ -1433,6 +1499,8 @@ int stmpe_remove(struct stmpe *stmpe)
 	if (!IS_ERR(stmpe->vcc))
 		regulator_disable(stmpe->vcc);
 
+	__stmpe_disable(stmpe, STMPE_BLOCK_ADC);
+
 	mfd_remove_devices(stmpe->dev);
 
 	return 0;

include/linux/mfd/stmpe.h

@@ -21,6 +21,9 @@
 #define STMPE_I_DRIVE(x)	(x & 0x1)
 #define STMPE_OP_MODE(x)	((x & 0x7) << 1)
 
+#define STMPE811_REG_ADC_CTRL1	0x20
+#define STMPE811_REG_ADC_CTRL2	0x21
+
 struct device;
 struct regulator;
 
@@ -134,6 +137,12 @@ struct stmpe {
 	u8 ier[2];
 	u8 oldier[2];
 	struct stmpe_platform_data *pdata;
+
+	/* For devices that use an ADC */
+	u8 sample_time;
+	u8 mod_12b;
+	u8 ref_sel;
+	u8 adc_freq;
 };
 
 extern int stmpe_reg_write(struct stmpe *stmpe, u8 reg, u8 data);
@@ -147,6 +156,7 @@ extern int stmpe_set_altfunc(struct stmpe *stmpe, u32 pins,
 			     enum stmpe_block block);
 extern int stmpe_enable(struct stmpe *stmpe, unsigned int blocks);
 extern int stmpe_disable(struct stmpe *stmpe, unsigned int blocks);
+extern int stmpe811_adc_common_init(struct stmpe *stmpe);
 
 #define STMPE_GPIO_NOREQ_811_TOUCH	(0xf0)