[PATCH 4/6] button: add a simple ADC-based button driver
Simon Glass
sjg at chromium.org
Mon Dec 21 17:46:59 CET 2020
Hi Marek,
On Mon, 21 Dec 2020 at 02:34, Marek Szyprowski <m.szyprowski at samsung.com> wrote:
>
> Hi Simon,
>
> On 19.12.2020 03:28, Simon Glass wrote:
> > On Mon, 14 Dec 2020 at 04:25, Marek Szyprowski <m.szyprowski at samsung.com> wrote:
> >> Add a simple ADC-based button driver. This driver binds to the 'adc-keys'
> >> device tree node.
I think it is best to copy it exactly as is.
Regards,
Simon
> >>
> >> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> >> Change-Id: I6da7101eff3ce53766d899f49f5839d728d52fb3
> >> ---
> >> drivers/button/Kconfig | 8 +++
> >> drivers/button/Makefile | 1 +
> >> drivers/button/button-adc.c | 117 ++++++++++++++++++++++++++++++++++++
> >> 3 files changed, 126 insertions(+)
> >> create mode 100644 drivers/button/button-adc.c
> >>
> >> diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig
> >> index 6b3ec7e55de..283367f2bd3 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 ADC lines. 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 fcc10ebe8db..bbd18af1494 100644
> >> --- a/drivers/button/Makefile
> >> +++ b/drivers/button/Makefile
> >> @@ -3,4 +3,5 @@
> >> # Copyright (C) 2020 Philippe Reynes <philippe.reynes at 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 00000000000..086c676c02a
> >> --- /dev/null
> >> +++ b/drivers/button/button-adc.c
> >> @@ -0,0 +1,117 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * Copyright (C) 2020 Samsung Electronics Co., Ltd.
> >> + * http://www.samsung.com
> >> + * Author: Marek Szyprowski <m.szyprowski at samsung.com>
> >> + */
> >> +
> >> +#include <common.h>
> >> +#include <button.h>
> >> +#include <dm.h>
> >> +#include <dm/lists.h>
> >> +#include <dm/uclass-internal.h>
> >> +#include <log.h>
> >> +#include <adc.h>
> > Please check header order
> >
> > https://protect2.fireeye.com/v1/url?k=0827922c-57bcaba3-08261963-0cc47a31307c-c2add94742a708a4&q=1&e=e6ddd072-23a6-4591-9ca7-8d41aa498536&u=https%3A%2F%2Fwww.denx.de%2Fwiki%2FU-Boot%2FCodingStyle
> >
> >> +
> >> +struct button_adc_priv {
> >> + struct udevice *adc;
> >> + int channel;
> > comments
> >
> >> +};
> >> +
> >> +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_name(UCLASS_ADC, ofnode_get_name(args.node),
> >> + &priv->adc);
> > How about uclass_get_device_by_ofnode() ?
> >
> >> + 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);
> >> + if (ret)
> >> + return ret;
> >> + uc_plat = dev_get_uclass_platdata(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" },
> > Please add the binding file for this.
> Do you want me to copy the
> Documentation/devicetree/bindings/input/adc-keys.txt file from Linux
> kernel to doc/device-tree-bindings/input or should I modify it somehow?
> (drop all the ignored properties?)
> >> + { }
> >> +};
> >> +
> >> +U_BOOT_DRIVER(button_adc) = {
> >> + .name = "button_adc",
> >> + .id = UCLASS_BUTTON,
> >> + .of_match = button_adc_ids,
> >> + .ops = &button_adc_ops,
> >> + .priv_auto_alloc_size = sizeof(struct button_adc_priv),
> >> + .bind = button_adc_bind,
> >> + .probe = button_adc_probe,
> >> +};
> >> --
> >> 2.17.1
> >>
> > Regards,
> > Simon
> >
> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland
>
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