- adds adc-keys button driver

- fix meson-saradc driver to get reference voltage
 - add adc-keys test for sandbox
 - enable adc-keys for VIM3 & VIM3L boards
 - fix button.h build
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Merge tag 'u-boot-amlogic-20210222' of https://gitlab.denx.de/u-boot/custodians/u-boot-amlogic

- adds adc-keys button driver
- fix meson-saradc driver to get reference voltage
- add adc-keys test for sandbox
- enable adc-keys for VIM3 & VIM3L boards
- fix button.h build

arch/sandbox/dts/test.dts

@@ -2,6 +2,7 @@
 
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/gpio/sandbox-gpio.h>
+#include <dt-bindings/input/input.h>
 #include <dt-bindings/pinctrl/sandbox-pinmux.h>
 #include <dt-bindings/mux/mux.h>
 
@@ -69,6 +70,30 @@
 		};
 	};
 
+	buttons2 {
+		compatible = "adc-keys";
+		io-channels = <&adc 3>;
+		keyup-threshold-microvolt = <3000000>;
+
+		button-up {
+			label = "button3";
+			linux,code = <KEY_F3>;
+			press-threshold-microvolt = <1500000>;
+		};
+
+		button-down {
+			label = "button4";
+			linux,code = <KEY_F4>;
+			press-threshold-microvolt = <1000000>;
+		};
+
+		button-enter {
+			label = "button5";
+			linux,code = <KEY_F5>;
+			press-threshold-microvolt = <500000>;
+		};
+	};
+
 	cros_ec: cros-ec {
 		reg = <0 0>;
 		compatible = "google,cros-ec-sandbox";
@@ -608,8 +633,9 @@
 		i2c-eeprom = <&bootcount_i2c>;
 	};
 
-	adc@0 {
+	adc: adc@0 {
 		compatible = "sandbox,adc";
+		#io-channel-cells = <1>;
 		vdd-supply = <&buck2>;
 		vss-microvolts = <0>;
 	};

configs/khadas-vim3_defconfig

@@ -31,6 +31,8 @@ CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_ADC=y
 CONFIG_SARADC_MESON=y
+CONFIG_BUTTON=y
+CONFIG_BUTTON_ADC=y
 CONFIG_DM_I2C=y
 CONFIG_SYS_I2C_MESON=y
 CONFIG_DM_MMC=y

configs/khadas-vim3l_defconfig

@@ -31,6 +31,8 @@ CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_ADC=y
 CONFIG_SARADC_MESON=y
+CONFIG_BUTTON=y
+CONFIG_BUTTON_ADC=y
 CONFIG_DM_I2C=y
 CONFIG_SYS_I2C_MESON=y
 CONFIG_DM_MMC=y

configs/sandbox_defconfig

@@ -123,6 +123,7 @@ CONFIG_DM_BOOTCOUNT=y
 CONFIG_DM_BOOTCOUNT_RTC=y
 CONFIG_DM_BOOTCOUNT_I2C_EEPROM=y
 CONFIG_BUTTON=y
+CONFIG_BUTTON_ADC=y
 CONFIG_BUTTON_GPIO=y
 CONFIG_CLK=y
 CONFIG_CLK_COMPOSITE_CCF=y

doc/device-tree-bindings/input/adc-keys.txt

@@ -0,0 +1,67 @@
+ADC attached resistor ladder buttons
+------------------------------------
+
+Required properties:
+ - compatible: "adc-keys"
+ - io-channels: Phandle to an ADC channel
+ - io-channel-names = "buttons";
+ - keyup-threshold-microvolt: Voltage above or equal to which all the keys are
+			      considered up.
+
+Optional properties:
+	- poll-interval: Poll interval time in milliseconds
+	- autorepeat: Boolean, Enable auto repeat feature of Linux input
+	  subsystem.
+
+Each button (key) is represented as a sub-node of "adc-keys":
+
+Required subnode-properties:
+	- label: Descriptive name of the key.
+	- linux,code: Keycode to emit.
+	- press-threshold-microvolt: voltage above or equal to which this key is
+				     considered pressed.
+
+No two values of press-threshold-microvolt may be the same.
+All values of press-threshold-microvolt must be less than
+keyup-threshold-microvolt.
+
+Example:
+
+#include <dt-bindings/input/input.h>
+
+	adc-keys {
+		compatible = "adc-keys";
+		io-channels = <&lradc 0>;
+		io-channel-names = "buttons";
+		keyup-threshold-microvolt = <2000000>;
+
+		button-up {
+			label = "Volume Up";
+			linux,code = <KEY_VOLUMEUP>;
+			press-threshold-microvolt = <1500000>;
+		};
+
+		button-down {
+			label = "Volume Down";
+			linux,code = <KEY_VOLUMEDOWN>;
+			press-threshold-microvolt = <1000000>;
+		};
+
+		button-enter {
+			label = "Enter";
+			linux,code = <KEY_ENTER>;
+			press-threshold-microvolt = <500000>;
+		};
+	};
+
++--------------------------------+------------------------+
+| 2.000.000 <= value             | no key pressed         |
++--------------------------------+------------------------+
+| 1.500.000 <= value < 2.000.000 | KEY_VOLUMEUP pressed   |
++--------------------------------+------------------------+
+| 1.000.000 <= value < 1.500.000 | KEY_VOLUMEDOWN pressed |
++--------------------------------+------------------------+
+|   500.000 <= value < 1.000.000 | KEY_ENTER pressed      |
++--------------------------------+------------------------+
+|              value <   500.000 | no key pressed         |
++--------------------------------+------------------------+

drivers/adc/meson-saradc.c

@@ -18,6 +18,7 @@
 #include <linux/delay.h>
 #include <linux/math64.h>
 #include <linux/bitfield.h>
+#include <power/regulator.h>
 
 #define MESON_SAR_ADC_REG0					0x00
 	#define MESON_SAR_ADC_REG0_PANEL_DETECT			BIT(31)
@@ -656,7 +657,10 @@ static int meson_saradc_stop(struct udevice *dev)
 
 static int meson_saradc_probe(struct udevice *dev)
 {
+	struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
 	struct meson_saradc_priv *priv = dev_get_priv(dev);
+	struct udevice *vref;
+	int vref_uv;
 	int ret;
 
 	ret = regmap_init_mem(dev_ofnode(dev), &priv->regmap);
@@ -675,6 +679,23 @@ static int meson_saradc_probe(struct udevice *dev)
 
 	priv->active_channel = -1;
 
+	ret = device_get_supply_regulator(dev, "vref-supply", &vref);
+	if (ret) {
+		printf("can't get vref-supply: %d\n", ret);
+		return ret;
+	}
+
+	vref_uv = regulator_get_value(vref);
+	if (vref_uv < 0) {
+		printf("can't get vref-supply value: %d\n", vref_uv);
+		return vref_uv;
+	}
+
+	/* VDD supplied by common vref pin */
+	uc_pdata->vdd_supply = vref;
+	uc_pdata->vdd_microvolts = vref_uv;
+	uc_pdata->vss_microvolts = 0;
+
 	return 0;
 }
 

drivers/button/Kconfig

@@ -9,6 +9,14 @@ config BUTTON
 	  can provide access to board-specific buttons. Use of the device tree
 	  for configuration is encouraged.
 
+config BUTTON_ADC
+	bool "Button adc"
+	depends on BUTTON
+	help
+	  Enable support for buttons which are connected to Analog to Digital
+	  Converter device. The ADC driver must use driver model. Buttons are
+	  configured using the device tree.
+
 config BUTTON_GPIO
 	bool "Button gpio"
 	depends on BUTTON

drivers/button/Makefile

@@ -3,4 +3,5 @@
 # Copyright (C) 2020 Philippe Reynes <philippe.reynes@softathome.com>
 
 obj-$(CONFIG_BUTTON) += button-uclass.o
+obj-$(CONFIG_BUTTON_ADC) += button-adc.o
 obj-$(CONFIG_BUTTON_GPIO) += button-gpio.o

drivers/button/button-adc.c

@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
+ */
+
+#include <common.h>
+#include <adc.h>
+#include <button.h>
+#include <log.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/of_access.h>
+#include <dm/uclass-internal.h>
+
+/**
+ * struct button_adc_priv - private data for button-adc driver.
+ *
+ * @adc: Analog to Digital Converter device to which button is connected.
+ * @channel: channel of the ADC device to probe the button state.
+ * @min: minimal uV value to consider button as pressed.
+ * @max: maximal uV value to consider button as pressed.
+ */
+struct button_adc_priv {
+	struct udevice *adc;
+	int channel;
+	int min;
+	int max;
+};
+
+static enum button_state_t button_adc_get_state(struct udevice *dev)
+{
+	struct button_adc_priv *priv = dev_get_priv(dev);
+	unsigned int val;
+	int ret, uV;
+
+	ret = adc_start_channel(priv->adc, priv->channel);
+	if (ret)
+		return ret;
+
+	ret = adc_channel_data(priv->adc, priv->channel, &val);
+	if (ret)
+		return ret;
+
+	ret = adc_raw_to_uV(priv->adc, val, &uV);
+	if (ret)
+		return ret;
+
+	return (uV >= priv->min && uV < priv->max) ? BUTTON_ON : BUTTON_OFF;
+}
+
+static int button_adc_of_to_plat(struct udevice *dev)
+{
+	struct button_uc_plat *uc_plat = dev_get_uclass_plat(dev);
+	struct button_adc_priv *priv = dev_get_priv(dev);
+	struct ofnode_phandle_args args;
+	u32 treshold, up_treshold, t;
+	ofnode node;
+	int ret;
+
+	/* Ignore the top-level button node */
+	if (!uc_plat->label)
+		return 0;
+
+	ret = dev_read_phandle_with_args(dev->parent, "io-channels",
+					 "#io-channel-cells", 0, 0, &args);
+	if (ret)
+		return ret;
+
+	ret = uclass_get_device_by_ofnode(UCLASS_ADC, args.node, &priv->adc);
+	if (ret)
+		return ret;
+
+	ret = ofnode_read_u32(dev_ofnode(dev->parent),
+			      "keyup-threshold-microvolt", &up_treshold);
+	if (ret)
+		return ret;
+
+	ret = ofnode_read_u32(dev_ofnode(dev), "press-threshold-microvolt",
+			      &treshold);
+	if (ret)
+		return ret;
+
+	dev_for_each_subnode(node, dev->parent) {
+		ret = ofnode_read_u32(node, "press-threshold-microvolt", &t);
+		if (ret)
+			return ret;
+
+		if (t > treshold)
+			up_treshold = t;
+	}
+
+	priv->channel = args.args[0];
+	priv->min = treshold;
+	priv->max = up_treshold;
+
+	return ret;
+}
+
+static int button_adc_bind(struct udevice *parent)
+{
+	struct udevice *dev;
+	ofnode node;
+	int ret;
+
+	dev_for_each_subnode(node, parent) {
+		struct button_uc_plat *uc_plat;
+		const char *label;
+
+		label = ofnode_read_string(node, "label");
+		if (!label) {
+			debug("%s: node %s has no label\n", __func__,
+			      ofnode_get_name(node));
+			return -EINVAL;
+		}
+		ret = device_bind_driver_to_node(parent, "button_adc",
+						 ofnode_get_name(node),
+						 node, &dev);
+		if (ret)
+			return ret;
+		uc_plat = dev_get_uclass_plat(dev);
+		uc_plat->label = label;
+	}
+
+	return 0;
+}
+
+static const struct button_ops button_adc_ops = {
+	.get_state	= button_adc_get_state,
+};
+
+static const struct udevice_id button_adc_ids[] = {
+	{ .compatible = "adc-keys" },
+	{ }
+};
+
+U_BOOT_DRIVER(button_adc) = {
+	.name		= "button_adc",
+	.id		= UCLASS_BUTTON,
+	.of_match	= button_adc_ids,
+	.ops		= &button_adc_ops,
+	.priv_auto	= sizeof(struct button_adc_priv),
+	.bind		= button_adc_bind,
+	.of_to_plat	= button_adc_of_to_plat,
+};

include/button.h

@@ -6,6 +6,8 @@
 #ifndef __BUTTON_H
 #define __BUTTON_H
 
+struct udevice;
+
 /**
  * struct button_uc_plat - Platform data the uclass stores about each device
  *

test/dm/button.c

@@ -7,7 +7,10 @@
 
 #include <common.h>
 #include <dm.h>
+#include <adc.h>
 #include <button.h>
+#include <power/regulator.h>
+#include <power/sandbox_pmic.h>
 #include <asm/gpio.h>
 #include <dm/test.h>
 #include <test/ut.h>
@@ -17,11 +20,20 @@ static int dm_test_button_base(struct unit_test_state *uts)
 {
 	struct udevice *dev;
 
-	/* Get the top-level device */
+	/* Get the top-level gpio buttons device */
 	ut_assertok(uclass_get_device(UCLASS_BUTTON, 0, &dev));
+	/* Get the 2 gpio buttons */
 	ut_assertok(uclass_get_device(UCLASS_BUTTON, 1, &dev));
 	ut_assertok(uclass_get_device(UCLASS_BUTTON, 2, &dev));
-	ut_asserteq(-ENODEV, uclass_get_device(UCLASS_BUTTON, 3, &dev));
+
+	/* Get the top-level adc buttons device */
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 3, &dev));
+	/* Get the 3 adc buttons */
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 4, &dev));
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 5, &dev));
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 6, &dev));
+
+	ut_asserteq(-ENODEV, uclass_get_device(UCLASS_BUTTON, 7, &dev));
 
 	return 0;
 }
@@ -72,3 +84,37 @@ static int dm_test_button_label(struct unit_test_state *uts)
 	return 0;
 }
 DM_TEST(dm_test_button_label, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
+
+/* Test adc-keys driver */
+static int dm_test_button_keys_adc(struct unit_test_state *uts)
+{
+	struct udevice *supply;
+	struct udevice *dev;
+	int uV;
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_ADC, "adc@0", &dev));
+
+	ut_assertok(regulator_get_by_devname(SANDBOX_BUCK2_DEVNAME, &supply));
+	ut_assertok(regulator_set_value(supply, SANDBOX_BUCK2_SET_UV));
+	ut_asserteq(SANDBOX_BUCK2_SET_UV, regulator_get_value(supply));
+	/* Update ADC plat and get new Vdd value */
+	ut_assertok(adc_vdd_value(dev, &uV));
+	ut_asserteq(SANDBOX_BUCK2_SET_UV, uV);
+
+	/*
+	 * sandbox-adc returns constant value on channel 3, is used by adc-keys:
+	 * SANDBOX_ADC_CHANNEL3_DATA * SANDBOX_BUCK2_SET_UV / SANDBOX_ADC_DATA_MASK =
+	 * 0x3000 * 3300000 / 0xffff = 618759uV
+	 * This means that button3 and button4 are released and button5
+	 * is pressed.
+	 */
+	ut_assertok(button_get_by_label("button3", &dev));
+	ut_asserteq(BUTTON_OFF, button_get_state(dev));
+	ut_assertok(button_get_by_label("button4", &dev));
+	ut_asserteq(BUTTON_OFF, button_get_state(dev));
+	ut_assertok(button_get_by_label("button5", &dev));
+	ut_asserteq(BUTTON_ON, button_get_state(dev));
+
+	return 0;
+}
+DM_TEST(dm_test_button_keys_adc, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);