Hi Oleh, On Fri, Jun 04, 2021 at 12:54:42AM +0300, Oleh Kravchenko wrote: > Hello Jeff, > thank you for your code-review. > > Could you please clarify a few things below? > Just for my better understanding. > > > 03.06.21 17:38, Jeff LaBundy пише: > > Hi Oleh, > > > > This cleaned up rather nicely; just a few more comments from myself. > > > > On Wed, Jun 02, 2021 at 10:05:04PM +0300, Oleh Kravchenko wrote: > >> A simple analog joystick built on Low Power ATtiny85 Microcontroller. > >> Directional movements are measured with two 10 kΩ potentiometers > >> connected with a gimbal mechanism that separates the horizontal and > >> vertical movements. This joystick also has a select button that is actuated > >> when the joystick is pressed down. > >> > >> Input events polled over the I2C bus. > >> > >> Product page: > >> https://www.sparkfun.com/products/15168 > >> Firmware and hardware sources: > >> https://github.com/sparkfun/Qwiic_Joystick > >> > >> Tested on RPi4B and O4-iMX-NANO boards. > >> > >> Cc: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > >> Cc: Device Tree mailing list <devicetree@xxxxxxxxxxxxxxx> > >> Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> > >> Cc: Jiri Kosina <jikos@xxxxxxxx> > >> Cc: Patchwork Bot <patchwork-bot@xxxxxxxxxx> > >> Cc: Rob Herring <robh@xxxxxxxxxx> > >> Signed-off-by: Oleh Kravchenko <oleg@xxxxxxxxxx> > > > > Typically a binding patch should be first in the series (i.e. [1/2]) > > with the driver next (i.e. [2/2]) so that checkpatch does not signal > > a warning about an undocumented compatible string. > > > >> --- > >> > >> Changes: > >> - update code after code review > >> > >> drivers/input/joystick/Kconfig | 9 ++ > >> drivers/input/joystick/Makefile | 1 + > >> drivers/input/joystick/qwiic-joystick.c | 147 ++++++++++++++++++++++++ > >> 3 files changed, 157 insertions(+) > >> create mode 100644 drivers/input/joystick/qwiic-joystick.c > >> > >> diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig > >> index 5e38899058c1..7dfe8ea90923 100644 > >> --- a/drivers/input/joystick/Kconfig > >> +++ b/drivers/input/joystick/Kconfig > >> @@ -372,6 +372,15 @@ config JOYSTICK_PXRC > >> To compile this driver as a module, choose M here: the > >> module will be called pxrc. > >> > >> +config JOYSTICK_QWIIC > >> + tristate "SparkFun Qwiic Joystick" > >> + depends on I2C > >> + help > >> + Say Y here if you want to use the SparkFun Qwiic Joystick. > >> + > >> + To compile this driver as a module, choose M here: the > >> + module will be called qwiic-joystick. > >> + > >> config JOYSTICK_FSIA6B > >> tristate "FlySky FS-iA6B RC Receiver" > >> select SERIO > >> diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile > >> index 31d720c9e493..5174b8aba2dd 100644 > >> --- a/drivers/input/joystick/Makefile > >> +++ b/drivers/input/joystick/Makefile > >> @@ -27,6 +27,7 @@ obj-$(CONFIG_JOYSTICK_MAPLE) += maplecontrol.o > >> obj-$(CONFIG_JOYSTICK_N64) += n64joy.o > >> obj-$(CONFIG_JOYSTICK_PSXPAD_SPI) += psxpad-spi.o > >> obj-$(CONFIG_JOYSTICK_PXRC) += pxrc.o > >> +obj-$(CONFIG_JOYSTICK_QWIIC) += qwiic-joystick.o > >> obj-$(CONFIG_JOYSTICK_SIDEWINDER) += sidewinder.o > >> obj-$(CONFIG_JOYSTICK_SPACEBALL) += spaceball.o > >> obj-$(CONFIG_JOYSTICK_SPACEORB) += spaceorb.o > >> diff --git a/drivers/input/joystick/qwiic-joystick.c b/drivers/input/joystick/qwiic-joystick.c > >> new file mode 100644 > >> index 000000000000..59c0f3e6ee75 > >> --- /dev/null > >> +++ b/drivers/input/joystick/qwiic-joystick.c > >> @@ -0,0 +1,147 @@ > >> +// SPDX-License-Identifier: GPL-2.0 > >> +/* > >> + * Copyright (C) 2021 Oleh Kravchenko <oleg@xxxxxxxxxx> > >> + * > >> + * SparkFun Qwiic Joystick > >> + * Product page:https://www.sparkfun.com/products/15168 > >> + * Firmware and hardware sources:https://github.com/sparkfun/Qwiic_Joystick > >> + */ > >> + > >> +#include <linux/bits.h> > >> +#include <linux/i2c.h> > >> +#include <linux/input.h> > > > > Now that you are using byte order macros, you should explicitly include > > linux/kernel.h. > > Where is requirement is described? > I've found a lot of drivers without including linux/kernel.h but linux/bits.h It's actually asm/byteorder.h that defines these; I mention linux/kernel.h as it includes it anyway. I think either is fine for this driver. > > >> +#include <linux/module.h> > >> + > >> +#define DRV_NAME "qwiic-joystick" > >> + > >> +#define QWIIC_JSK_REG_VERS 0 > >> +#define QWIIC_JSK_REG_DATA 3 > >> + > >> +#define QWIIC_JSK_MAX_AXIS GENMASK(9, 0) > >> +#define QWIIC_JSK_FUZZ 2 > >> +#define QWIIC_JSK_FLAT 2 > >> +#define QWIIC_JSK_POLL_INTERVAL 16 > >> +#define QWIIC_JSK_POLL_MIN 8 > >> +#define QWIIC_JSK_POLL_MAX 32 > >> + > >> +struct qwiic_jsk { > >> + char phys[32]; > >> + struct input_dev *dev; > >> + struct i2c_client *client; > >> +}; > > > > Nit: no need to align these declarations (here and a few other places). > > > >> + > >> +struct qwiic_ver { > >> + u8 addr; > >> + u8 major; > >> + u8 minor; > >> +} __packed; > > > > 'addr' is unused so it can be dropped, in which case QWIIC_JSK_REG_VERS > > would need to be increased to 1. > > > >> + > >> +struct qwiic_data { > >> + __be16 x; > >> + __be16 y; > >> + u8 thumb; > >> +} __packed; > >> + > >> +static void qwiic_poll(struct input_dev *input) > >> +{ > >> + struct qwiic_jsk *priv; > >> + struct qwiic_data data; > >> + int err; > >> + > >> + priv = input_get_drvdata(input); > >> + > >> + err = i2c_smbus_read_i2c_block_data(priv->client, QWIIC_JSK_REG_DATA, > >> + sizeof(data), (u8 *)&data); > >> + if (err != sizeof(data)) > >> + return; > >> + > >> + input_report_abs(input, ABS_X, be16_to_cpu(data.x) >> 6); > >> + input_report_abs(input, ABS_Y, be16_to_cpu(data.y) >> 6); > >> + input_report_key(input, BTN_THUMBL, !data.thumb); > >> + input_sync(input); > >> +} > >> + > >> +static int qwiic_probe(struct i2c_client *client, > >> + const struct i2c_device_id *id) > >> +{ > >> + struct qwiic_jsk *priv; > >> + struct qwiic_ver vers; > >> + int err; > >> + > >> + err = i2c_smbus_read_i2c_block_data(client, QWIIC_JSK_REG_VERS, > >> + sizeof(vers), (u8 *)&vers); > >> + if (0 <= err && err < sizeof(vers)) > >> + err = -EIO; > >> + if (err < 0) > >> + return err; > > > > I think this reads a little simpler as: > > > > if (err < 0) > > return err; > > if (err != sizeof(vers)) > > return -EIO; > > > > Can we sure that i2c_smbus_read_i2c_block_data() will read exact numbers of bytes? > And if it read less, will return it an error? I think it's highly unlikely an adapter would perform an incomplete transfer without returning an error. However, this behavior is technically defined by the adapter itself. As such, I think it's prudent to validate the entire range of return values. If for some reason i2c_smbus_read_i2c_block_data() returned 1, vers.minor is garbage and you must bail or retry. My point from your original patch was that you should not squash every value below sizeof(vers) as -EIO. In case i2c_smbus_read_i2c_block_data() returned a different negative value, you should return that from probe. > > >> + > >> + dev_dbg(&client->dev, "SparkFun Qwiic Joystick, FW: %d.%d\n", > >> + vers.major, vers.minor); > > > > These should be printed as %u. > > > >> + > >> + priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); > >> + if (!priv) > >> + return -ENOMEM; > >> + > >> + priv->client = client; > >> + snprintf(priv->phys, sizeof(priv->phys), > >> + "i2c/%s", dev_name(&client->dev)); > >> + i2c_set_clientdata(client, priv); > >> + > >> + priv->dev = devm_input_allocate_device(&client->dev); > >> + if (!priv->dev) > >> + return -ENOMEM; > >> + > >> + priv->dev->id.bustype = BUS_I2C; > >> + priv->dev->name = "SparkFun Qwiic Joystick"; > >> + priv->dev->phys = priv->phys; > >> + input_set_drvdata(priv->dev, priv); > >> + > >> + input_set_abs_params(priv->dev, ABS_X, 0, QWIIC_JSK_MAX_AXIS, > >> + QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT); > >> + input_set_abs_params(priv->dev, ABS_Y, 0, QWIIC_JSK_MAX_AXIS, > >> + QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT); > >> + input_set_capability(priv->dev, EV_KEY, BTN_THUMBL); > >> + > >> + err = input_setup_polling(priv->dev, qwiic_poll); > >> + if (err) { > >> + dev_err(&client->dev, "failed to set up polling: %d\n", err); > >> + return err; > >> + } > >> + input_set_poll_interval(priv->dev, QWIIC_JSK_POLL_INTERVAL); > >> + input_set_min_poll_interval(priv->dev, QWIIC_JSK_POLL_MIN); > >> + input_set_max_poll_interval(priv->dev, QWIIC_JSK_POLL_MAX); > >> + > >> + err = input_register_device(priv->dev); > >> + if (err) > >> + dev_err(&client->dev, "failed to register joystick: %d\n", err); > >> + > >> + return err; > >> +} > >> + > >> +#ifdef CONFIG_OF > >> +static const struct of_device_id of_qwiic_match[] = { > >> + { .compatible = "sparkfun,qwiic-joystick", }, > >> + { }, > >> +}; > >> +MODULE_DEVICE_TABLE(of, of_qwiic_match); > >> +#endif /* CONFIG_OF */ > >> + > >> +static const struct i2c_device_id qwiic_id_table[] = { > >> + { KBUILD_MODNAME, 0 }, > >> + { }, > >> +}; > >> +MODULE_DEVICE_TABLE(i2c, qwiic_id_table); > >> + > >> +static struct i2c_driver qwiic_driver = { > >> + .driver = { > >> + .name = DRV_NAME, > >> + .of_match_table = of_match_ptr(of_qwiic_match), > >> + }, > >> + .id_table = qwiic_id_table, > >> + .probe = qwiic_probe, > >> +}; > >> +module_i2c_driver(qwiic_driver); > >> + > >> +MODULE_AUTHOR("Oleh Kravchenko <oleg@xxxxxxxxxx>"); > >> +MODULE_DESCRIPTION("SparkFun Qwiic Joystick driver"); > >> +MODULE_LICENSE("GPL v2"); > >> -- > >> 2.26.3 > >> > > > > Kind regards, > > Jeff LaBundy > > > > -- > Best regards, > Oleh Kravchenko > Kind regards, Jeff LaBundy
