Re: [PATCH v3 1/2] Input: cypress-sf - Add Cypress StreetFighter touchkey driver

On Mon, Sep 6 2021 at 10:31:42 +0400, Dmitry Torokhov 
[off-list ref] wrote:

Hi Yassine,

On Wed, Sep 01, 2021 at 04:52:58PM +0000, Yassine Oudjana wrote:

quoted

 This adds support for Cypress StreetFighter touchkey controllers 
such as sf3155.
 This driver supports managing regulators and generating input 
events.

 Due to lack of documentation, this driver is entirely based on 
information
 gathered from a driver written for an old Android kernel fork[1][2].

 Signed-off-by: Yassine Oudjana [off-list ref]

Thank you for the patch. Please run your patches through 
checkpatch.pl.

Sure.

See additional comments below.

quoted

 [1] 
https://github.com/LineageOS/android_kernel_xiaomi_msm8996/blob/lineage-18.1/drivers/input/touchscreen/cyttsp_button.c
 [2] 
https://github.com/LineageOS/android_kernel_xiaomi_msm8996/blob/lineage-18.1/arch/arm/boot/dts/qcom/a4-msm8996-mtp.dtsi#L291-L314
 ---
 Changes since v2:
  - Code style fixes.
  - Added copyright statement.
 Changes since v1:
  - Changed version variables in probe to int to allow storing error 
codes.

  drivers/input/keyboard/Kconfig      |  10 ++
  drivers/input/keyboard/Makefile     |   1 +
  drivers/input/keyboard/cypress-sf.c | 223 
++++++++++++++++++++++++++++
  3 files changed, 234 insertions(+)
  create mode 100644 drivers/input/keyboard/cypress-sf.c

 diff --git a/drivers/input/keyboard/Kconfig 
b/drivers/input/keyboard/Kconfig
 index 40a070a2e7f5..6f3fbea8b803 100644
 --- a/drivers/input/keyboard/Kconfig
 +++ b/drivers/input/keyboard/Kconfig
 @@ -788,4 +788,14 @@ config KEYBOARD_MTK_PMIC
  	  To compile this driver as a module, choose M here: the
  	  module will be called pmic-keys.

 +config KEYBOARD_CYPRESS_SF
 +	tristate "Cypress StreetFighter touchkey support"
 +	depends on I2C
 +	help
 +	  Say Y here if you want to enable support for Cypress 
StreetFighter
 +	  touchkeys.
 +
 +	  To compile this driver as a module, choose M here: the
 +	  module will be called cypress-sf.
 +
  endif
 diff --git a/drivers/input/keyboard/Makefile 
b/drivers/input/keyboard/Makefile
 index 1d689fdd5c00..e3c8648f834e 100644
 --- a/drivers/input/keyboard/Makefile
 +++ b/drivers/input/keyboard/Makefile
 @@ -17,6 +17,7 @@ obj-$(CONFIG_KEYBOARD_BCM)		+= bcm-keypad.o
  obj-$(CONFIG_KEYBOARD_CAP11XX)		+= cap11xx.o
  obj-$(CONFIG_KEYBOARD_CLPS711X)		+= clps711x-keypad.o
  obj-$(CONFIG_KEYBOARD_CROS_EC)		+= cros_ec_keyb.o
 +obj-$(CONFIG_KEYBOARD_CYPRESS_SF)	+= cypress-sf.o
  obj-$(CONFIG_KEYBOARD_DAVINCI)		+= davinci_keyscan.o
  obj-$(CONFIG_KEYBOARD_DLINK_DIR685)	+= dlink-dir685-touchkeys.o
  obj-$(CONFIG_KEYBOARD_EP93XX)		+= ep93xx_keypad.o
 diff --git a/drivers/input/keyboard/cypress-sf.c 
b/drivers/input/keyboard/cypress-sf.c
 new file mode 100644
 index 000000000000..f2862547f633
 --- /dev/null
 +++ b/drivers/input/keyboard/cypress-sf.c
 @@ -0,0 +1,223 @@
 +// SPDX-License-Identifier: GPL-2.0-only
 +/*
 + * Cypress StreetFighter Touchkey Driver
 + *
 + * Copyright (c) 2021 Yassine Oudjana [off-list ref]
 + */
 +
 +#include <linux/bitops.h>
 +#include <linux/device.h>
 +#include <linux/i2c.h>
 +#include <linux/input.h>
 +#include <linux/interrupt.h>
 +#include <linux/module.h>
 +#include <linux/pm.h>
 +#include <linux/regulator/consumer.h>
 +
 +#define CYPRESS_SF_DEV_NAME "cypress-sf"
 +
 +#define CYPRESS_SF_REG_FW_VERSION	0x46
 +#define CYPRESS_SF_REG_HW_VERSION	0x48
 +#define CYPRESS_SF_REG_BUTTON_STATUS	0x4a
 +
 +struct cypress_sf_data {
 +	struct i2c_client *client;
 +	struct input_dev *input_dev;
 +	struct regulator_bulk_data regulators[2];
 +	u32 *keycodes;
 +	unsigned long keystates;
 +	int num_keys;
 +};
 +
 +static irqreturn_t cypress_sf_irq_handler(int irq, void *devid)
 +{
 +	struct cypress_sf_data *touchkey = devid;
 +	unsigned long keystates;
 +	bool curr_state, new_state;
 +	int key;
 +
 +	keystates = i2c_smbus_read_byte_data(touchkey->client,
 +					CYPRESS_SF_REG_BUTTON_STATUS);
 +	if (keystates < 0) {

keystates is declared as unsigned, so this condition will never 
trigger.

Right. I'll change it.

quoted

 +		dev_err(&touchkey->client->dev, "Failed to read button status");
 +		return IRQ_NONE;
 +	}
 +
 +	for(key = 0; key < touchkey->num_keys; ++key) {
 +		curr_state = test_bit(key, &touchkey->keystates);
 +		new_state = test_bit(key, &keystates);
 +
 +		if(curr_state ^ new_state) {

Instead of this please do

	bitmap_xor(&changed, &keystates, &touchkey->keystates,
		   touchkey->num_keys);
	for_each_set_bit(key, &changed, touchkey->num_keys) {
		...
	}

Noted.

quoted

 +			dev_dbg(&touchkey->client->dev,\
 +				"Key %d changed to %d", key, new_state);
 +			input_report_key(touchkey->input_dev,
 +					touchkey->keycodes[key],
 +					new_state);
 +		}
 +	}
 +	input_sync(touchkey->input_dev);
 +	touchkey->keystates = keystates;
 +
 +	return IRQ_HANDLED;
 +}
 +
 +static int cypress_sf_probe(struct i2c_client *client,
 +				const struct i2c_device_id *id)
 +{
 +	struct cypress_sf_data *touchkey;
 +	int hw_version, fw_version;
 +	int i, ret;
 +
 +	touchkey = devm_kzalloc(&client->dev, sizeof(*touchkey), 
GFP_KERNEL);
 +	if(!touchkey)
 +		return -ENOMEM;
 +
 +	touchkey->client = client;
 +	i2c_set_clientdata(client, touchkey);
 +
 +	touchkey->regulators[0].supply = "vdd";
 +	touchkey->regulators[1].supply = "avdd";
 +
 +	ret = devm_regulator_bulk_get(&client->dev,
 +					ARRAY_SIZE(touchkey->regulators),
 +					touchkey->regulators);
 +	if(ret) {
 +		dev_err(&client->dev, "Failed to get regulators: %d\n", ret);
 +		return ret;
 +	}
 +
 +	touchkey->num_keys = 
of_property_count_elems_of_size(client->dev.of_node,
 +							"linux,keycodes",
 +							sizeof(u32));

Please use device_property_* API instead of of_property_*.

Noted.

quoted

 +	if(touchkey->num_keys < 0)
 +		/* Default key count */
 +		touchkey->num_keys = 2;
 +
 +	touchkey->keycodes = devm_kzalloc(&client->dev,
 +				sizeof(u32) * touchkey->num_keys, GFP_KERNEL);
 +	if(!touchkey->keycodes)
 +		return -ENOMEM;
 +
 +	ret = of_property_read_u32_array(client->dev.of_node, 
"linux,keycodes",
 +						touchkey->keycodes, touchkey->num_keys);
 +
 +	if(touchkey->num_keys < 0) {
 +		/* Default keycodes */
 +		touchkey->keycodes[0] = KEY_BACK;
 +		touchkey->keycodes[1] = KEY_MENU;
 +	}
 +
 +	ret = regulator_bulk_enable(ARRAY_SIZE(touchkey->regulators),
 +					touchkey->regulators);

Please call variables that carry error core or 0 for success 'error'.

I'll rename them.

quoted

 +	if(ret) {
 +		dev_err(&client->dev, "Failed to enable regulators: %d\n", ret);
 +		return ret;
 +	}
 +
 +	touchkey->input_dev = devm_input_allocate_device(&client->dev);
 +	if(!touchkey->input_dev) {
 +		dev_err(&client->dev, "Failed to allocate input device\n");
 +		return -ENOMEM;
 +	}
 +
 +	touchkey->input_dev->name = CYPRESS_SF_DEV_NAME;
 +	touchkey->input_dev->id.bustype = BUS_I2C;
 +
 +	hw_version = i2c_smbus_read_byte_data(touchkey->client,
 +				CYPRESS_SF_REG_HW_VERSION);
 +	fw_version = i2c_smbus_read_word_data(touchkey->client,
 +				CYPRESS_SF_REG_FW_VERSION);
 +	if(hw_version < 0 || fw_version < 0)
 +		dev_warn(&client->dev, "Failed to read versions\n");
 +	else
 +		dev_info(&client->dev, "HW version %d, FW version %d\n",
 +				hw_version, fw_version);

Why is this needed?

I was using it as an indicator for success finding the chip, but it 
isn't
strictly needed. I'll remove it.

quoted

 +
 +	for(i = 0; i < touchkey->num_keys; ++i)
 +		input_set_capability(touchkey->input_dev, EV_KEY,
 +					touchkey->keycodes[i]);
 +
 +	ret = input_register_device(touchkey->input_dev);
 +	if(ret) {
 +		dev_err(&client->dev,
 +			"Failed to register input device: %d\n", ret);
 +		return ret;
 +	}
 +
 +	ret = devm_request_threaded_irq(&client->dev, client->irq,
 +					NULL, cypress_sf_irq_handler,
 +					IRQF_ONESHOT,
 +					CYPRESS_SF_DEV_NAME, touchkey);
 +	if(ret) {
 +		dev_err(&client->dev,
 +			"Failed to register threaded irq: %d", ret);
 +		return ret;
 +	}
 +
 +	return 0;
 +};
 +
 +static int __maybe_unused cypress_sf_suspend(struct device *dev) {
 +	struct i2c_client *client = to_i2c_client(dev);
 +	struct cypress_sf_data *touchkey = i2c_get_clientdata(client);
 +	int ret;
 +
 +	disable_irq(client->irq);
 +	ret = regulator_bulk_disable(ARRAY_SIZE(touchkey->regulators),
 +					touchkey->regulators);
 +	if(ret) {
 +		dev_err(dev, "Failed to disable regulators: %d", ret);
 +		enable_irq(client->irq);
 +		return ret;
 +	}
 +	dev_dbg(dev, "Suspended device");
 +
 +	return 0;
 +}
 +
 +static int __maybe_unused cypress_sf_resume(struct device *dev) {
 +	struct i2c_client *client = to_i2c_client(dev);
 +	struct cypress_sf_data *touchkey = i2c_get_clientdata(client);
 +	int ret;
 +
 +	ret = regulator_bulk_enable(ARRAY_SIZE(touchkey->regulators),
 +					touchkey->regulators);
 +	if(ret) {
 +		dev_err(dev, "Failed to enable regulators: %d", ret);
 +		return ret;
 +	}
 +	enable_irq(client->irq);
 +	dev_dbg(dev, "Resumed device");
 +
 +	return 0;
 +}
 +
 +static SIMPLE_DEV_PM_OPS(cypress_sf_pm_ops,
 +			 cypress_sf_suspend, cypress_sf_resume);
 +
 +static struct i2c_device_id cypress_sf_id_table[] = {
 +	{ CYPRESS_SF_DEV_NAME, 0 },
 +	{ }
 +};
 +MODULE_DEVICE_TABLE(i2c, cypress_sf_id_table);
 +
 +static const struct of_device_id cypress_sf_of_match[] = {
 +	{ .compatible = "cypress,sf3155", },
 +	{ },
 +};
 +MODULE_DEVICE_TABLE(of, cypress_sf_of_match);
 +
 +static struct i2c_driver cypress_sf_driver = {
 +	.driver = {
 +		.name = CYPRESS_SF_DEV_NAME,
 +		.pm = &cypress_sf_pm_ops,
 +		.of_match_table = of_match_ptr(cypress_sf_of_match),
 +	},
 +	.id_table = cypress_sf_id_table,
 +	.probe = cypress_sf_probe,
 +};
 +module_i2c_driver(cypress_sf_driver);
 +
 +MODULE_AUTHOR("Yassine Oudjana [off-list ref]");
 +MODULE_DESCRIPTION("Cypress StreetFighter Touchkey Driver");
 +MODULE_LICENSE("GPL v2");
 --
 2.33.0

Thanks.

--
Dmitry

Thanks for the review!
Yassine