[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <a38609ed1d2a181287f4758e3272c553@bootlin.com>
Date: Fri, 12 Jul 2024 11:07:43 +0200
From: Kamel BOUHARA <kamel.bouhara@...tlin.com>
To: Jeff LaBundy <jeff@...undy.com>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>, Rob Herring
<robh+dt@...nel.org>, Krzysztof Kozlowski
<krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>,
Henrik Rydberg <rydberg@...math.org>, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, Marco Felsch
<m.felsch@...gutronix.de>, catalin.popescu@...ca-geosystems.com,
mark.satterthwaite@...chnetix.com, Thomas Petazzoni
<thomas.petazzoni@...tlin.com>, Gregory Clement
<gregory.clement@...tlin.com>, bsp-development.geo@...ca-geosystems.com
Subject: Re: [PATCH v16 3/3] Input: Add TouchNetix axiom i2c touchscreen
driver
Le 2024-07-07 21:20, Jeff LaBundy a écrit :
> Hi Kamel,
>
Hello Jeff,
> On Wed, Jul 03, 2024 at 04:25:18PM +0200, Kamel Bouhara wrote:
>> Add a new driver for the TouchNetix's axiom family of
>> touchscreen controllers. This driver only supports i2c
>> and can be later adapted for SPI and USB support.
>>
>> Signed-off-by: Kamel Bouhara <kamel.bouhara@...tlin.com>
>> ---
>
> This is coming together nicely; just a few trailing comments on
> top of Marco's feedback.
>
>> MAINTAINERS | 1 +
>> drivers/input/touchscreen/Kconfig | 14 +
>> drivers/input/touchscreen/Makefile | 1 +
>> drivers/input/touchscreen/touchnetix_axiom.c | 616
>> +++++++++++++++++++
>> 4 files changed, 632 insertions(+)
>> create mode 100644 drivers/input/touchscreen/touchnetix_axiom.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 2041384d3866..ac6b612bfbba 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -22745,6 +22745,7 @@ M: Kamel Bouhara <kamel.bouhara@...tlin.com>
>> L: linux-input@...r.kernel.org
>> S: Maintained
>>
>> F: Documentation/devicetree/bindings/input/touchscreen/touchnetix,ax54a.yaml
>> +F: drivers/input/touchscreen/touchnetix_axiom.c
>>
>> TPM DEVICE DRIVER
>> M: Peter Huewe <peterhuewe@....de>
>> diff --git a/drivers/input/touchscreen/Kconfig
>> b/drivers/input/touchscreen/Kconfig
>> index c821fe3ee794..1ce8f1c25625 100644
>> --- a/drivers/input/touchscreen/Kconfig
>> +++ b/drivers/input/touchscreen/Kconfig
>> @@ -834,6 +834,20 @@ config TOUCHSCREEN_MIGOR
>> To compile this driver as a module, choose M here: the
>> module will be called migor_ts.
>>
>> +config TOUCHSCREEN_TOUCHNETIX_AXIOM
>> + tristate "TouchNetix AXIOM based touchscreen controllers"
>> + depends on I2C
>> + select CRC16
>> + select REGMAP_I2C
>> + help
>> + Say Y here if you have a axiom touchscreen connected to
>> + your system.
>> +
>> + If unsure, say N.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called axiom.
>> +
>> config TOUCHSCREEN_TOUCHRIGHT
>> tristate "Touchright serial touchscreen"
>> select SERIO
>> diff --git a/drivers/input/touchscreen/Makefile
>> b/drivers/input/touchscreen/Makefile
>> index a81cb5aa21a5..6ce7b804adc7 100644
>> --- a/drivers/input/touchscreen/Makefile
>> +++ b/drivers/input/touchscreen/Makefile
>> @@ -91,6 +91,7 @@ obj-$(CONFIG_TOUCHSCREEN_SUR40) += sur40.o
>> obj-$(CONFIG_TOUCHSCREEN_SURFACE3_SPI) += surface3_spi.o
>> obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC) += ti_am335x_tsc.o
>> obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213) += touchit213.o
>> +obj-$(CONFIG_TOUCHSCREEN_TOUCHNETIX_AXIOM) += touchnetix_axiom.o
>> obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT) += touchright.o
>> obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN) += touchwin.o
>> obj-$(CONFIG_TOUCHSCREEN_TS4800) += ts4800-ts.o
>> diff --git a/drivers/input/touchscreen/touchnetix_axiom.c
>> b/drivers/input/touchscreen/touchnetix_axiom.c
>> new file mode 100644
>> index 000000000000..cea52dafc913
>> --- /dev/null
>> +++ b/drivers/input/touchscreen/touchnetix_axiom.c
>> @@ -0,0 +1,616 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * TouchNetix axiom Touchscreen Driver
>> + *
>> + * Copyright (C) 2020-2023 TouchNetix Ltd.
>> + *
>> + * Author(s): Bart Prescott <bartp@...sheep.co.uk>
>> + * Pedro Torruella <pedro.torruella@...chnetix.com>
>> + * Mark Satterthwaite <mark.satterthwaite@...chnetix.com>
>> + * Hannah Rossiter <hannah.rossiter@...chnetix.com>
>> + * Kamel Bouhara <kamel.bouhara@...tlin.com>
>> + *
>> + */
>
> Please include bits.h as well.
>
Ack, thanks !
[...]
>> +/*
>> + * axiom devices are typically configured to report touches at a rate
>> + * of 100Hz (10ms) for systems that require polling for reports.
>> + * When reports are polled, it will be expected to occasionally
>> + * observe the overflow bit being set in the reports.
>> + * This indicates that reports are not being read fast enough.
>
> This comment is strange; if reports are not read quickly enough at
> the default rate, why not set the default rate at the slowest for
> which the overflow bit is not set?
>
The rate has been set to the give a good user experience regardless of
this overflow bit that isn't even processed here.
>> + */
>> +#define POLL_INTERVAL_DEFAULT_MS 10
>> +
>> +/* Translate usage/page/offset triplet into physical address. */
>> +static u16 axiom_usage_to_target_address(struct axiom_data *ts, u8
>> usage, u8 page,
>> + char offset)
>> +{
>> + /* At the moment the convention is that u31 is always at physical
>> address 0x0 */
>> + if (!ts->usage_table_populated) {
>> + if (usage == AXIOM_DEVINFO_USAGE_ID)
>> + return ((page << 8) + offset);
>> + else
>> + return 0xffff;
>
> Checkpatch normally gripes if an else follows a return; did that not
> happen here? You should simplify it either way:
>
> if (...) {
> if (...)
> return ...;
>
> return U16_MAX;
> }
>
Fixed thanks !
No, checkpatch didn't raised any issue here with "--strict", am I
missing something ?
>> + }
>> +
>> + if (page >= ts->usage_table[usage].num_pages) {
>> + dev_err(ts->dev, "Invalid usage table! usage: u%02x, page: %02x,
>> offset: %02x\n",
>> + usage, page, offset);
>> + return 0xffff;
>> + }
>> +
>> + return ((ts->usage_table[usage].start_page + page) << 8) + offset;
>> +}
>> +
>> +static int axiom_read(struct axiom_data *ts, u8 usage, u8 page, void
>> *buf, u16 len)
>> +{
>> + union axiom_cmd_header cmd_header;
>> + int ret;
>
> For consistency, please use 'error' as is done throughout.
>
Sure, thanks.
>> +
>> + cmd_header.head.target_address =
>> + cpu_to_le16(axiom_usage_to_target_address(ts, usage, page, 0));
>> + cmd_header.head.length = cpu_to_le16(len |
>> AXIOM_CMD_HEADER_READ_MASK);
>> +
>> + ret = regmap_write(ts->regmap, le32_to_cpu(cmd_header.preamble), 0);
>> + if (ret) {
>> + dev_err(ts->dev, "failed to write preamble, error %d\n", ret);
>> + return ret;
>> + }
>> +
>> + ret = regmap_raw_read(ts->regmap, 0, buf, len);
>> + if (ret) {
>> + dev_err(ts->dev, "failed to read target address %04x, error %d\n",
>> + cmd_header.head.target_address, ret);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * One of the main purposes for reading the usage table is to
>> identify
>> + * which usages reside at which target address.
>> + * When performing subsequent reads or writes to AXIOM, the target
>> address
>> + * is used to specify which usage is being accessed.
>> + * Consider the following discovery code which will build up the
>> usage table.
>> + */
>> +static u32 axiom_populate_usage_table(struct axiom_data *ts)
>> +{
>> + struct axiom_usage_entry *usage_table;
>> + u8 *rx_data = ts->rx_buf;
>> + u32 max_report_len = 0;
>> + u32 usage_id;
>> + int error;
>> +
>> + usage_table = ts->usage_table;
>> +
>> + /* Read the second page of usage u31 to get the usage table */
>> + error = axiom_read(ts, AXIOM_DEVINFO_USAGE_ID, 1, rx_data,
>> + (AXIOM_U31_BYTES_PER_USAGE * ts->devinfo.num_usages));
>> +
>> + if (error)
>> + return error;
>> +
>> + for (usage_id = 0; usage_id < ts->devinfo.num_usages; usage_id++) {
>> + u16 offset = (usage_id * AXIOM_U31_BYTES_PER_USAGE);
>> + u8 id = rx_data[offset + 0];
>> + u8 start_page = rx_data[offset + 1];
>> + u8 num_pages = rx_data[offset + 2];
>> + u32 max_offset = ((rx_data[offset + 3] & AXIOM_PAGE_OFFSET_MASK) +
>> 1) * 2;
>> +
>> + usage_table[id].is_report = !num_pages;
>> +
>> + /* Store the entry into the usage table */
>> + usage_table[id].id = id;
>> + usage_table[id].start_page = start_page;
>> + usage_table[id].num_pages = num_pages;
>> +
>> + dev_dbg(ts->dev, "Usage u%02x Info: %*ph\n", id,
>> AXIOM_U31_BYTES_PER_USAGE,
>> + &rx_data[offset]);
>> +
>> + /* Identify the max report length the module will receive */
>> + if (usage_table[id].is_report && max_offset > max_report_len)
>> + max_report_len = max_offset;
>> + }
>> +
>> + ts->usage_table_populated = true;
>> +
>> + return max_report_len;
>> +}
>> +
>> +static int axiom_discover(struct axiom_data *ts)
>> +{
>> + int error;
>> +
>> + /*
>> + * Fetch the first page of usage u31 to get the
>> + * device information and the number of usages
>> + */
>> + error = axiom_read(ts, AXIOM_DEVINFO_USAGE_ID, 0, &ts->devinfo,
>> AXIOM_U31_PAGE0_LENGTH);
>
> It seems a little safer, and more intuitive, to pass
> sizeof(ts->devinfo) instead
> of AXIOM_U31_PAGE0_LENGTH. To that end, devinfo is only 11 bytes in
> size, but
> you're reading 12 bytes. I'm guessing the compiler is padding
> axiom_data which is
> the only reason the existing implementation seems to work.
>
OK, I tough this actually could be good to keep this as it help knowing
which register/page
is used to gatter device information here.
I'll however take your suggestion, thanks !
[...]
>> +
>> + /* Enables the raw data for up to 4 force channels to be sent to the
>> input subsystem */
>> + set_bit(EV_MSC, input_dev->evbit);
>> + /* Declare that we support "RAW" Miscellaneous events */
>> + set_bit(MSC_RAW, input_dev->mscbit);
>
> Neither of these event types are reported; please drop them.
>
Fixed.
>> +
>> + ts->input_dev = input_dev;
>> + input_set_drvdata(ts->input_dev, ts);
>> +
>> + /* Ensure that all reports are initialised to not be present. */
>> + for (target = 0; target < AXIOM_U41_MAX_TARGETS; target++)
>> + ts->targets[target].state = AXIOM_TARGET_STATE_NOT_PRESENT;
>> +
>> + if (client->irq) {
>> + error = devm_request_threaded_irq(dev, client->irq, NULL,
>> + axiom_irq, IRQF_ONESHOT, dev_name(dev), ts);
>> + if (error)
>> + dev_err_probe(dev, error, "failed to request irq");
>> + } else {
>> + error = input_setup_polling(input_dev, axiom_i2c_poll);
>> + if (error)
>> + return dev_err_probe(ts->dev, error, "Unable to set up polling
>> mode\n");
>> +
>> + if (!device_property_read_u32(ts->dev, "poll-interval",
>> &poll_interval))
>> + input_set_poll_interval(input_dev, poll_interval);
>> + else
>> + input_set_poll_interval(input_dev, POLL_INTERVAL_DEFAULT_MS);
>> + }
>> +
>> + error = input_register_device(input_dev);
>> + if (error)
>> + return dev_err_probe(ts->dev, error, "failed to register input
>> device\n");
>> +
>> + return 0;
>> +}
>> +
>> +static const struct i2c_device_id axiom_i2c_id_table[] = {
>> + { "ax54a" },
>> + { },
>
> Please drop the comma after the sentinel as was done below.
>
Fixed, thanks.
>> +};
>> +MODULE_DEVICE_TABLE(i2c, axiom_i2c_id_table);
>> +
>> +static const struct of_device_id axiom_i2c_of_match[] = {
>> + { .compatible = "touchnetix,ax54a", },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(of, axiom_i2c_of_match);
>> +
>> +static struct i2c_driver axiom_i2c_driver = {
>> + .driver = {
>> + .name = "axiom",
>> + .of_match_table = axiom_i2c_of_match,
>> + },
>> + .id_table = axiom_i2c_id_table,
>> + .probe = axiom_i2c_probe,
>> +};
>> +module_i2c_driver(axiom_i2c_driver);
>> +
>> +MODULE_AUTHOR("Bart Prescott <bartp@...sheep.co.uk>");
>> +MODULE_AUTHOR("Pedro Torruella <pedro.torruella@...chnetix.com>");
>> +MODULE_AUTHOR("Mark Satterthwaite
>> <mark.satterthwaite@...chnetix.com>");
>> +MODULE_AUTHOR("Hannah Rossiter <hannah.rossiter@...chnetix.com>");
>> +MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@...tlin.com>");
>> +MODULE_DESCRIPTION("TouchNetix axiom touchscreen I2C bus driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.25.1
>>
>
> Kind regards,
> Jeff LaBundy
Thanks for this review !
--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
Powered by blists - more mailing lists