Hi, On Tue, 22 Dec 2020 at 02:46, Heinrich Schuchardt <xypron.g...@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.szyprow...@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 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 > > 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.rey...@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.szyprow...@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
