Hi,
On Tue, 22 Dec 2020 at 02:46, Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On 12/22/20 9:56 AM, Marek Szyprowski wrote:
Add a simple Analog to Digital Converter device based button driver. This driver binds to the 'adc-keys' device tree node.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com
drivers/button/Kconfig | 8 +++ drivers/button/Makefile | 1 + drivers/button/button-adc.c | 121 ++++++++++++++++++++++++++++++++++++ 3 files changed, 130 insertions(+) create mode 100644 drivers/button/button-adc.c
diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig index 6b3ec7e55d..6db3c5e93a 100644 --- a/drivers/button/Kconfig +++ b/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 BUTTONhelpEnable support for buttons which are connected to Analog to DigitalConverter device. The ADC driver must use driver model. Buttons areconfigured using the device tree.- config BUTTON_GPIO bool "Button gpio" depends on BUTTON
diff --git a/drivers/button/Makefile b/drivers/button/Makefile index fcc10ebe8d..bbd18af149 100644 --- a/drivers/button/Makefile +++ b/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 diff --git a/drivers/button/button-adc.c b/drivers/button/button-adc.c new file mode 100644 index 0000000000..bf99dd8b43 --- /dev/null +++ b/drivers/button/button-adc.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- Copyright (C) 2020 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 <dm.h> +#include <dm/lists.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.
- */
+struct button_adc_priv {
struct udevice *adc;int channel;+};
+static enum button_state_t button_adc_get_state(struct udevice *dev) +{
struct button_adc_priv *priv = dev_get_priv(dev);unsigned int val, mask;int ret;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_data_mask(priv->adc, &mask);if (ret)return ret;/* getting state is simplified a bit */if (ret == 0)return (val < mask / 2) ? BUTTON_ON : BUTTON_OFF;return ret;+}
+static int button_adc_probe(struct udevice *dev) +{
struct button_uc_plat *uc_plat = dev_get_uclass_platdata(dev);struct button_adc_priv *priv = dev_get_priv(dev);struct ofnode_phandle_args args;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;priv->channel = args.args[0];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);This code does not match the binding. The binding defines a voltage ladder where you have multiple voltage ranges and multiple buttons.
You need to consider the threshold voltages.
Have a look at Linux' drivers/input/keyboard/adc-keys.c. Beware that code is also incorrect as the author ignores the meaning of "threshold" and uses it it as closest voltage.
Apart from that, from a DM point of view, this looks good.
Regards, Simon