dm: adc: Add driver for Rockchip SARADC

The ADC can support some channels signal-ended some bits Successive Approximation
Register (SAR) A/D Converter, like 6-channel and 10-bit. It converts the analog
input signal into some bits binary digital codes.

Signed-off-by: David Wu <david.wu@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

drivers/adc/Kconfig

@@ -28,3 +28,12 @@ config ADC_SANDBOX
 	  - 4 analog input channels
 	  - 16-bit resolution
 	  - single and multi-channel conversion mode
+
+config SARADC_ROCKCHIP
+	bool "Enable Rockchip SARADC driver"
+	help
+	  This enables driver for Rockchip SARADC.
+	  It provides:
+	  - 2~6 analog input channels
+	  - 1O or 12 bits resolution
+	  - Up to 1MSPS of sample rate

drivers/adc/Makefile

@@ -8,3 +8,4 @@
 obj-$(CONFIG_ADC) += adc-uclass.o
 obj-$(CONFIG_ADC_EXYNOS) += exynos-adc.o
 obj-$(CONFIG_ADC_SANDBOX) += sandbox.o
+obj-$(CONFIG_SARADC_ROCKCHIP) += rockchip-saradc.o

drivers/adc/rockchip-saradc.c

@@ -0,0 +1,183 @@
+/*
+ * (C) Copyright 2017, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Rockchip SARADC driver for U-Boot
+ */
+
+#include <common.h>
+#include <adc.h>
+#include <clk.h>
+#include <dm.h>
+#include <errno.h>
+#include <asm/io.h>
+
+#define SARADC_CTRL_CHN_MASK		GENMASK(2, 0)
+#define SARADC_CTRL_POWER_CTRL		BIT(3)
+#define SARADC_CTRL_IRQ_ENABLE		BIT(5)
+#define SARADC_CTRL_IRQ_STATUS		BIT(6)
+
+#define SARADC_TIMEOUT			(100 * 1000)
+
+struct rockchip_saradc_regs {
+	unsigned int data;
+	unsigned int stas;
+	unsigned int ctrl;
+	unsigned int dly_pu_soc;
+};
+
+struct rockchip_saradc_data {
+	int				num_bits;
+	int				num_channels;
+	unsigned long			clk_rate;
+};
+
+struct rockchip_saradc_priv {
+	struct rockchip_saradc_regs		*regs;
+	int					active_channel;
+	const struct rockchip_saradc_data	*data;
+};
+
+int rockchip_saradc_channel_data(struct udevice *dev, int channel,
+				 unsigned int *data)
+{
+	struct rockchip_saradc_priv *priv = dev_get_priv(dev);
+	struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+
+	if (channel != priv->active_channel) {
+		error("Requested channel is not active!");
+		return -EINVAL;
+	}
+
+	if ((readl(&priv->regs->ctrl) & SARADC_CTRL_IRQ_STATUS) !=
+	    SARADC_CTRL_IRQ_STATUS)
+		return -EBUSY;
+
+	/* Read value */
+	*data = readl(&priv->regs->data);
+	*data &= uc_pdata->data_mask;
+
+	/* Power down adc */
+	writel(0, &priv->regs->ctrl);
+
+	return 0;
+}
+
+int rockchip_saradc_start_channel(struct udevice *dev, int channel)
+{
+	struct rockchip_saradc_priv *priv = dev_get_priv(dev);
+
+	if (channel < 0 || channel >= priv->data->num_channels) {
+		error("Requested channel is invalid!");
+		return -EINVAL;
+	}
+
+	/* 8 clock periods as delay between power up and start cmd */
+	writel(8, &priv->regs->dly_pu_soc);
+
+	/* Select the channel to be used and trigger conversion */
+	writel(SARADC_CTRL_POWER_CTRL | (channel & SARADC_CTRL_CHN_MASK) |
+	       SARADC_CTRL_IRQ_ENABLE, &priv->regs->ctrl);
+
+	priv->active_channel = channel;
+
+	return 0;
+}
+
+int rockchip_saradc_stop(struct udevice *dev)
+{
+	struct rockchip_saradc_priv *priv = dev_get_priv(dev);
+
+	/* Power down adc */
+	writel(0, &priv->regs->ctrl);
+
+	priv->active_channel = -1;
+
+	return 0;
+}
+
+int rockchip_saradc_probe(struct udevice *dev)
+{
+	struct rockchip_saradc_priv *priv = dev_get_priv(dev);
+	struct clk clk;
+	int ret;
+
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret)
+		return ret;
+
+	ret = clk_set_rate(&clk, priv->data->clk_rate);
+	if (IS_ERR_VALUE(ret))
+		return ret;
+
+	priv->active_channel = -1;
+
+	return 0;
+}
+
+int rockchip_saradc_ofdata_to_platdata(struct udevice *dev)
+{
+	struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+	struct rockchip_saradc_priv *priv = dev_get_priv(dev);
+	struct rockchip_saradc_data *data;
+
+	data = (struct rockchip_saradc_data *)dev_get_driver_data(dev);
+	priv->regs = (struct rockchip_saradc_regs *)dev_read_addr(dev);
+	if (priv->regs == (struct rockchip_saradc_regs *)FDT_ADDR_T_NONE) {
+		error("Dev: %s - can't get address!", dev->name);
+		return -ENODATA;
+	}
+
+	priv->data = data;
+	uc_pdata->data_mask = (1 << priv->data->num_bits) - 1;;
+	uc_pdata->data_format = ADC_DATA_FORMAT_BIN;
+	uc_pdata->data_timeout_us = SARADC_TIMEOUT / 5;
+	uc_pdata->channel_mask = (1 << priv->data->num_channels) - 1;
+
+	return 0;
+}
+
+static const struct adc_ops rockchip_saradc_ops = {
+	.start_channel = rockchip_saradc_start_channel,
+	.channel_data = rockchip_saradc_channel_data,
+	.stop = rockchip_saradc_stop,
+};
+
+static const struct rockchip_saradc_data saradc_data = {
+	.num_bits = 10,
+	.num_channels = 3,
+	.clk_rate = 1000000,
+};
+
+static const struct rockchip_saradc_data rk3066_tsadc_data = {
+	.num_bits = 12,
+	.num_channels = 2,
+	.clk_rate = 50000,
+};
+
+static const struct rockchip_saradc_data rk3399_saradc_data = {
+	.num_bits = 10,
+	.num_channels = 6,
+	.clk_rate = 1000000,
+};
+
+static const struct udevice_id rockchip_saradc_ids[] = {
+	{ .compatible = "rockchip,saradc",
+	  .data = (ulong)&saradc_data },
+	{ .compatible = "rockchip,rk3066-tsadc",
+	  .data = (ulong)&rk3066_tsadc_data },
+	{ .compatible = "rockchip,rk3399-saradc",
+	  .data = (ulong)&rk3399_saradc_data },
+	{ }
+};
+
+U_BOOT_DRIVER(rockchip_saradc) = {
+	.name		= "rockchip_saradc",
+	.id		= UCLASS_ADC,
+	.of_match	= rockchip_saradc_ids,
+	.ops		= &rockchip_saradc_ops,
+	.probe		= rockchip_saradc_probe,
+	.ofdata_to_platdata = rockchip_saradc_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct rockchip_saradc_priv),
+};