Add ADC to mts-io

1 files changed, 126 insertions, 0 deletions

diff --git a/io-module/adc.c b/io-module/adc.c
new file mode 100644
index 0000000..3d5f3d0
--- /dev/null
+++ b/io-module/adc.c
@@ -0,0 +1,126 @@
+#define AT91SAM9X5_BASE_ADC     0xf804c000
+#define AT91SAM9260_BASE_ADC     0xfffe0000
+
+#define ADC_SHTIME_DEFAULT			0x05
+#define ADC_STARTUP_DEFAULT			0x04
+#define ADC_PRESCALE_DEFAULT			0x3F
+#define ADC_MODE_DEFAULT \
+	((ADC_SHTIME_DEFAULT & 0x0F) << 24) | \
+	((ADC_STARTUP_DEFAULT & 0x1F) << 16) | \
+	((ADC_PRESCALE_DEFAULT & 0x3F) << 8)
+
+#define ADC_CR_OFFSET			0x00
+#define ADC_MR_OFFSET			0x04
+#define ADC_CHER_OFFSET			0x10
+#define ADC_CHDR_OFFSET			0x14
+#define ADC_CHSR_OFFSET			0x18
+#define ADC_SR_OFFSET			0x1C
+#define ADC_LDCR_OFFSET			0x20
+#define ADC_IER_OFFSET			0x14
+#define ADC_IDR_OFFSET			0x28
+#define ADC_IMR_OFFSET			0x2C
+#define ADC_CDR0_OFFSET			0x30
+#define ADC_CDR1_OFFSET			0x34
+#define ADC_CDR2_OFFSET			0x38
+#define ADC_CDR3_OFFSET			0x3C
+
+void __iomem *adc_base;
+struct clk *adc_clk;
+
+#define ADC_CONVERT_RESET(base)			writel(0x01, (base) + ADC_CR_OFFSET)
+#define ADC_CONVERT_START(base)			writel(0x02, (base) + ADC_CR_OFFSET)
+
+static ssize_t mts_attr_show_adc(struct device *dev,
+			struct device_attribute *attr,
+			char *buf)
+{
+	int offset;
+	u32 value;
+	u32 chan_mask;
+
+	if (!DEVICE_CAPA(id_eeprom.capa, CAPA_ADC)) {
+		log_debug("ADC not available");
+		return -ENODEV;
+	}
+
+	if (!strcmp(attr->attr.name, "adc0")) {
+		offset = ADC_CDR0_OFFSET;
+		chan_mask = 0x01;
+	} else if (!strcmp(attr->attr.name, "adc1")) {
+		offset = ADC_CDR1_OFFSET;
+		chan_mask = 0x02;
+	} else if (!strcmp(attr->attr.name, "adc2")) {
+		offset = ADC_CDR2_OFFSET;
+		chan_mask = 0x04;
+	} else if (!strcmp(attr->attr.name, "adc3")) {
+		offset = ADC_CDR3_OFFSET;
+		chan_mask = 0x08;
+	} else {
+		log_notice("adc attr does not exist");
+		return -ENOENT;
+	}
+
+	mutex_lock(&mts_io_mutex);
+
+	// disable all channels and enable the one we want
+	writel(0x0F, adc_base + ADC_CHDR_OFFSET);
+	writel(chan_mask, adc_base + ADC_CHER_OFFSET);
+
+	ADC_CONVERT_START(adc_base);
+
+	// wait for conversion to complete (EOC bit set)
+	value = 0;
+	while (value != chan_mask) {
+		value = readl(adc_base + ADC_SR_OFFSET) & chan_mask;
+		log_debug("ADC_SR EOC [%X]", value);
+	}
+
+	// read result
+	value = readl(adc_base + offset);
+
+	mutex_unlock(&mts_io_mutex);
+
+	return sprintf(buf, "%lu\n", (unsigned long) value);
+}
+
+static DEVICE_ATTR_RO_MTS(dev_attr_adc0, "adc0", mts_attr_show_adc);
+static DEVICE_ATTR_RO_MTS(dev_attr_adc1, "adc1", mts_attr_show_adc);
+static DEVICE_ATTR_RO_MTS(dev_attr_adc2, "adc2", mts_attr_show_adc);
+static DEVICE_ATTR_RO_MTS(dev_attr_adc3, "adc3", mts_attr_show_adc);
+
+static int mts_io_board_adc_probe(struct platform_device *pdev)
+{
+	int err;
+	adc_clk = clk_get(&pdev->dev, "adc_clk");
+	if (adc_clk) {						
+		err = clk_prepare_enable(adc_clk);
+		if (err) {
+			log_error("clock failed to prepare+enable: %d\n", err);
+			return err;
+		}
+		#ifdef CONFIG_SOC_AT91SAM9X5
+		adc_base = ioremap(AT91SAM9X5_BASE_ADC, SZ_16K);
+		#else
+		adc_base = ioremap(AT91SAM9260_BASE_ADC, SZ_16K);
+		#endif
+		if (!adc_base) {
+			log_error("ioremap failed.\n");
+			return -ENOMEM;
+		}
+		ADC_CONVERT_RESET(adc_base);
+		writel(ADC_MODE_DEFAULT, adc_base + ADC_MR_OFFSET);
+		writel(0x000F0F0F, adc_base + ADC_IDR_OFFSET);
+		writel(0x0F, adc_base + ADC_CHDR_OFFSET);				
+	}
+	return 0;
+}
+
+static int mts_io_board_adc_remove(struct platform_device *pdev)
+{
+	if (adc_clk) {
+		int ret;
+		clk_disable_unprepare(adc_clk);									
+	}
+	return 0;
+}
+