On Thu, Sep 29, 2022 at 09:24:27AM -0700, Dmitry Torokhov wrote:
> Hi Chris,
>
> On Wed, Sep 28, 2022 at 04:48:06PM -0500, Chris Morgan wrote:
> > From: Chris Morgan <macromorgan@xxxxxxxxxxx>
> >
> > Add support for the Hynitron cst3xx controller found on devices such
> > as the Anbernic RG353P and RG353V (the Hynitron CST348). This driver
> > was built from sources provided by Hynitron to Anbernic (possibly
> > via Rockchip as an intermediary) and marked as GPLv2 in the code.
> > This driver was written strictly for the cst3xx series, but in
> > most places was left somewhat generic so support could be easily
> > added to other devices in the future.
>
> Thank you for the patches. This looks generally good, just a few
> suggestions below.
>
> >
> > Signed-off-by: Chris Morgan <macromorgan@xxxxxxxxxxx>
> > ---
> > drivers/input/touchscreen/Kconfig | 12 +
> > drivers/input/touchscreen/Makefile | 1 +
> > drivers/input/touchscreen/hynitron_cstxxx.c | 483 ++++++++++++++++++++
> > 3 files changed, 496 insertions(+)
> > create mode 100644 drivers/input/touchscreen/hynitron_cstxxx.c
> >
> > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > index 2d70c945b20a..9a9528e59c36 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -422,6 +422,18 @@ config TOUCHSCREEN_HYCON_HY46XX
> > To compile this driver as a module, choose M here: the
> > module will be called hycon-hy46xx.
> >
> > +config TOUCHSCREEN_HYNITRON_CSTXXX
> > + tristate "Hynitron touchscreen support"
> > + depends on I2C
> > + help
> > + Say Y here if you have a touchscreen using a Hynitron
> > + touchscreen controller.
> > +
> > + If unsure, say N.
> > +
> > + To compile this driver as a module, choose M here: the
> > + module will be called hynitron-cstxxx.
> > +
> > config TOUCHSCREEN_ILI210X
> > tristate "Ilitek ILI210X based touchscreen"
> > depends on I2C
> > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> > index 557f84fd2075..43860ca19b98 100644
> > --- a/drivers/input/touchscreen/Makefile
> > +++ b/drivers/input/touchscreen/Makefile
> > @@ -47,6 +47,7 @@ obj-$(CONFIG_TOUCHSCREEN_EXC3000) += exc3000.o
> > obj-$(CONFIG_TOUCHSCREEN_FUJITSU) += fujitsu_ts.o
> > obj-$(CONFIG_TOUCHSCREEN_GOODIX) += goodix_ts.o
> > obj-$(CONFIG_TOUCHSCREEN_HIDEEP) += hideep.o
> > +obj-$(CONFIG_TOUCHSCREEN_HYNITRON_CSTXXX) += hynitron_cstxxx.o
> > obj-$(CONFIG_TOUCHSCREEN_ILI210X) += ili210x.o
> > obj-$(CONFIG_TOUCHSCREEN_ILITEK) += ilitek_ts_i2c.o
> > obj-$(CONFIG_TOUCHSCREEN_IMAGIS) += imagis.o
> > diff --git a/drivers/input/touchscreen/hynitron_cstxxx.c b/drivers/input/touchscreen/hynitron_cstxxx.c
> > new file mode 100644
> > index 000000000000..e963968593c3
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/hynitron_cstxxx.c
> > @@ -0,0 +1,483 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Driver for Hynitron cstxxx Touchscreen
> > + *
> > + * Copyright (c) 2022 Chris Morgan <macromorgan@xxxxxxxxxxx>
> > + *
> > + * This code is based on hynitron_core.c authored by Hynitron.
> > + * Note that no datasheet was available, so much of these registers
> > + * are undocumented. This is essentially a cleaned-up version of the
> > + * vendor driver with support removed for hardware I cannot test and
> > + * device-specific functions replated with generic functions wherever
> > + * possible.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/gpio.h>
> > +#include <linux/i2c.h>
> > +#include <linux/input.h>
> > +#include <linux/input/mt.h>
> > +#include <linux/input/touchscreen.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +
> > +/* Per device data */
> > +struct hynitron_ts_platform_data {
>
> This better be called hynitron_ts_chip as we call "platform data"
> something that differs per-board, not per-chip version.
Acknowledged.
>
> > + unsigned int max_touch_num;
> > + u32 ic_chkcode;
> > + int (*firmware_info)(struct i2c_client *client);
> > + int (*bootloader_enter)(struct i2c_client *client);
> > + int (*init_input)(struct i2c_client *client);
> > + void (*report_touch)(struct i2c_client *client);
> > +};
> > +
> > +/* Data generic to all (supported and non-supported) controllers. */
> > +struct hynitron_ts_data {
> > + const struct hynitron_ts_platform_data *pdata;
> > + struct i2c_client *client;
> > + struct device *dev;
>
> Not sure if this really needed as I think everywhere you use it you also
> have "client->dev" available.
>
Acknowledged.
> > + struct input_dev *input_dev;
> > + struct touchscreen_properties prop;
> > + struct gpio_desc *reset_gpio;
> > + struct gpio_desc *irq_gpio;
>
> I do not believe this field is being used.
>
Acknowledged.
> > + u32 fw_version;
> > +};
> > +
> > +/*
> > + * Hard coded reset delay value of 20ms not IC dependent in
> > + * vendor driver.
> > + */
> > +void hyn_reset_proc(struct i2c_client *client, int delay)
> > +{
> > + struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
> > +
> > + gpiod_set_value(ts_data->reset_gpio, 1);
> > + mdelay(20);
> > + gpiod_set_value(ts_data->reset_gpio, 0);
>
> I think you can use gpiod_set_value_cansleep() in both places.
>
Acknowledged. I'll confirm it works and if so make the change. If not,
I'll note it in the next version notes.
> > + if (delay)
> > + mdelay(delay);
> > +}
> > +
> > +static irqreturn_t hyn_interrupt_handler(int irq, void *dev_id)
> > +{
> > + struct i2c_client *client = dev_id;
> > + struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
> > +
> > + ts_data->pdata->report_touch(client);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +/*
> > + * The vendor driver would retry twice before failing to read or write
> > + * to the i2c device.
> > + */
> > +int cst3xx_i2c_read(struct i2c_client *client,
> > + unsigned char *buf, int len)
> > +{
> > + int ret;
> > + int retries = 0;
> > +
> > + while (retries < 2) {
> > + ret = i2c_master_recv(client, buf, len);
> > + if (ret <= 0)
> > + retries++;
> > + else
> > + break;
> > + }
> > +
> > + return ret;
>
> I like when functions return 0 or negative, not positive (when
> possible). So I wonder if we should do something like:
>
Understood, I'll redo this to make it return 0 on success
instead of a positive value.
> if (ret == len)
> return 0;
>
> return ret < 0 ? ret : -EIO;
>
> and then in callers we can do:
>
> error = cst3xx_i2c_read(...)
> if (error)
> ...
>
> > +}
> > +
> > +int cst3xx_i2c_write(struct i2c_client *client,
> > + unsigned char *buf, int len)
> > +{
> > + int ret;
> > + int retries = 0;
> > +
> > + while (retries < 2) {
> > + ret = i2c_master_send(client, buf, len);
> > + if (ret <= 0)
> > + retries++;
> > + else
> > + break;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +int cst3xx_i2c_read_register(struct i2c_client *client,
> > + unsigned char *buf, int len)
>
Is my ignorance of the i2c protocol an acceptable answer? I'll try
this out on the next go-round.
> Why don't you have register as a separate u16 argument and then use
> cpu_to_le16[p] to convert to on-wire format.
>
> > +{
> > + int ret;
> > +
> > + ret = cst3xx_i2c_write(client, buf, 2);
> > + ret = cst3xx_i2c_read(client, buf, len);
>
> This clobbers errors from writing register. I also wonder if you can
> use i2c_transfer with 2 messages, one for writing register, and another
> for reading data.
>
> > +
> > + return ret;
> > +}
> > +
> > +int cst3xx_firmware_info(struct i2c_client *client)
> > +{
> > + struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
> > + int ret;
> > + u32 tmp;
> > + unsigned char buf[4];
> > +
> > + /*
> > + * Testing suggests command is required to allow reading of
> > + * firmware registers.
> > + */
> > + buf[0] = 0xd1;
> > + buf[1] = 0x01;
>
> I wonder if we can define some symbolic names for these.
>
I don't know what they mean, the best I can do is guess. No
datasheet sadly. I know from preliminary testing if I don't
send this initial command here the rest of them fail, so I
assume this command allows me to read certain registers?
> > + ret = cst3xx_i2c_write(client, buf, 2);
>
> This looks like a candidate for
>
> error = cst3xx_i2c_send_command(client, 0x01d1);
>
> helper that would wrap cst3xx_i2c_write.
Acknowledged.
>
> > + if (ret < 0)
> > + return -EIO;
> > +
> > + mdelay(10);
> > +
> > + /*
> > + * Read register for check-code to determine if device detected
> > + * correctly.
> > + */
> > + buf[0] = 0xd1;
> > + buf[1] = 0xfc;
> > + ret = cst3xx_i2c_read_register(client, buf, 4);
> > + if (ret < 0)
> > + return -EIO;
> > +
> > + memcpy(&tmp, buf, 4);
> > + if ((le32_to_cpu(tmp) & 0xffff0000) != ts_data->pdata->ic_chkcode) {
> > + dev_err(&client->dev, "%s ic mismatch\n", __func__);
> > + return -ENODEV;
> > + }
> > +
> > + mdelay(10);
> > +
> > + /* Read firmware version and test if firmware missing. */
> > + buf[0] = 0xd2;
> > + buf[1] = 0x08;
> > + ret = cst3xx_i2c_read_register(client, buf, 4);
> > + if (ret < 0)
> > + return -EIO;
> > +
> > + memcpy(&tmp, buf, 4);
> > +
> > + ts_data->fw_version = le32_to_cpu(tmp);
> > + if (ts_data->fw_version == 0xa5a5a5a5) {
> > + dev_err(&client->dev, "Device firmware missing\n");
> > + return -ENODEV;
> > + }
> > +
> > + /*
> > + * Testing suggests command required to exit register reading mode
> > + * and allow device to function as touchscreen.
> > + */
> > + buf[0] = 0xd1;
> > + buf[1] = 0x09;
> > + ret = cst3xx_i2c_write(client, buf, 2);
> > + if (ret < 0)
> > + return -EIO;
> > +
> > + mdelay(5);
> > +
> > + return 0;
> > +}
> > +
> > +int cst3xx_bootloader_enter(struct i2c_client *client)
> > +{
> > + int ret;
> > + u8 retry;
> > + unsigned char buf[4];
> > +
> > + for (retry = 0; retry < 5; retry++) {
> > + hyn_reset_proc(client, (7 + retry));
> > + /* set cmd to enter program mode */
> > + buf[0] = 0xa0;
> > + buf[1] = 0x01;
> > + buf[2] = 0xaa;
> > + ret = cst3xx_i2c_write(client, buf, 3);
> > + if (ret < 0)
> > + continue;
> > + mdelay(2);
> > +
> > + /* check whether in program mode */
> > + buf[0] = 0xa0;
> > + buf[1] = 0x02;
> > + ret = cst3xx_i2c_read_register(client, buf, 1);
> > +
> > + if (ret < 0)
> > + continue;
> > +
> > + if (buf[0] == 0xac)
> > + break;
> > + }
> > +
> > + if (buf[0] != 0xac) {
> > + dev_err(&client->dev, "%s unable to enter bootloader mode\n",
> > + __func__);
> > + return -ENODEV;
> > + }
> > +
> > + hyn_reset_proc(client, 40);
> > +
> > + return 0;
> > +}
> > +
> > +static void cst3xx_touch_update(struct hynitron_ts_data *ts_data, s32 id,
> > + s32 x, s32 y, s32 w)
> > +{
> > + input_mt_slot(ts_data->input_dev, id);
> > + input_mt_report_slot_state(ts_data->input_dev, MT_TOOL_FINGER, 1);
> > + touchscreen_report_pos(ts_data->input_dev, &ts_data->prop, x, y, true);
> > + input_report_abs(ts_data->input_dev, ABS_MT_TOUCH_MAJOR, w);
> > +}
> > +
> > +int cst3xx_finish_touch_read(struct i2c_client *client)
> > +{
> > + struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
> > + unsigned char buf[3];
> > + int ret;
> > +
> > + buf[0] = 0xd0;
> > + buf[1] = 0x00;
> > + buf[2] = 0xab;
> > + ret = cst3xx_i2c_write(ts_data->client, buf, 3);
> > + if (ret < 0) {
> > + dev_err(ts_data->dev, "send read touch info ending failed.\n");
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * Handle events from IRQ. Note that for cst3xx it appears that IRQ
> > + * fires continuously while touched, otherwise once every 1500ms
> > + * when not touched (assume touchscreen waking up periodically).
> > + */
> > +static void cst3xx_touch_report(struct i2c_client *client)
> > +{
> > + struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
> > + unsigned char buf[30];
> > + unsigned char finger_id, sw;
> > + unsigned int input_x = 0;
> > + unsigned int input_y = 0;
> > + unsigned int input_w = 0;
> > + int idx = 0;
> > + int i, ret;
> > + int touch_cnt, i2c_len;
> > +
> > + buf[0] = 0xd0;
> > + buf[1] = 0x00;
> > +
> > + /* Read and validate the first bits of input data. */
> > + ret = cst3xx_i2c_read_register(ts_data->client, buf, 7);
> > + if ((ret < 0) || (buf[6] != 0xab) || (buf[0] == 0xab))
> > + goto end;
> > +
> > + touch_cnt = buf[5] & 0x7f;
> > +
> > + /* If no touches registered, clear the input slots. */
> > + if (touch_cnt == 0) {
> > + input_mt_sync_frame(ts_data->input_dev);
> > + input_sync(ts_data->input_dev);
> > + return;
> > + }
> > +
> > + /*
> > + * If we have only one touch, we have enough data to process
> > + * the event. If we have more than one touch we need to read
> > + * the rest of the data. Note these functions are not combined
> > + * because this is how it was done in the vendor driver and I
> > + * lack the datasheet to modify the necessary values for
> > + * reading from all the registers at once.
> > + */
> > + if (touch_cnt > 1) {
> > + buf[5] = 0xd0;
> > + buf[6] = 0x07;
> > + i2c_len = (touch_cnt - 1) * 5 + 1;
> > + ret = cst3xx_i2c_read_register(ts_data->client,
> > + &buf[5], i2c_len);
> > + if (ret < 0)
> > + goto end;
> > + i2c_len += 5;
> > +
> > + if (buf[i2c_len - 1] != 0xab)
> > + goto end;
> > + }
> > +
> > + ret = cst3xx_finish_touch_read(client);
>
> Do we have to do this here? Can we jump to "end" label? The function
> looks a bit messy.
>
I'll see if I can clean it up better.
> > + if (ret < 0) {
> > + dev_err(ts_data->dev, "cst3xx touch read failure\n");
> > + return;
> > + }
> > +
> > + for (i = 0; i < touch_cnt; i++) {
> > + input_x = ((buf[idx + 1] << 4) | ((buf[idx + 3] >> 4) & 0x0f));
> > + input_y = ((buf[idx + 2] << 4) | (buf[idx + 3] & 0x0f));
> > + input_w = (buf[idx + 4] >> 3);
> > + sw = (buf[idx] & 0x0f) >> 1;
> > + finger_id = (buf[idx] >> 4) & 0x0f;
> > +
> > + /* Sanity check we don't have more fingers than we expect */
> > + if (ts_data->pdata->max_touch_num < finger_id) {
> > + dev_err(ts_data->dev, "cst3xx touch read failure\n");
> > + break;
> > + }
> > +
> > + /* sw value of 0 means no touch, 0x03 means touch */
> > + if (sw == 0x03)
> > + cst3xx_touch_update(ts_data, finger_id,
> > + input_x, input_y, input_w);
> > +
> > + idx += 5;
> > + }
> > +
> > + input_mt_sync_frame(ts_data->input_dev);
> > + input_sync(ts_data->input_dev);
> > + return;
> > +end:
> > + cst3xx_finish_touch_read(client);
> > + dev_err(ts_data->dev, "cst3xx touch read failure\n");
> > +}
> > +
> > +int cst3xx_input_dev_int(struct i2c_client *client)
> > +{
> > + struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
> > + int ret = 0;
>
> Call this variable "error" and not initialize to 0.
>
Acknowledged.
> > +
> > + ts_data->input_dev = devm_input_allocate_device(&ts_data->client->dev);
> > + if (!ts_data->input_dev) {
> > + dev_err(&ts_data->client->dev,
> > + "Failed to allocate input device.\n");
> > + return -ENOMEM;
> > + }
> > +
> > + ts_data->input_dev->name = "Hynitron cst3xx Touchscreen";
> > + ts_data->input_dev->phys = "input/ts";
> > + ts_data->input_dev->id.bustype = BUS_I2C;
> > + ts_data->input_dev->dev.parent = ts_data->dev;
>
> No need to set parent because devm_input_allocate_device() does this for
> us.
Thanks, I'll do that.
>
> > +
> > + input_set_drvdata(ts_data->input_dev, ts_data);
> > +
> > + input_set_capability(ts_data->input_dev, EV_ABS, ABS_MT_POSITION_X);
> > + input_set_capability(ts_data->input_dev, EV_ABS, ABS_MT_POSITION_Y);
> > + input_set_abs_params(ts_data->input_dev, ABS_MT_TOUCH_MAJOR,
> > + 0, 255, 0, 0);
> > +
> > + touchscreen_parse_properties(ts_data->input_dev, true, &ts_data->prop);
> > +
> > + if (!ts_data->prop.max_x || !ts_data->prop.max_y) {
> > + dev_err(&ts_data->client->dev,
> > + "Invalid x/y (%d, %d), using defaults\n",
> > + ts_data->prop.max_x, ts_data->prop.max_y);
> > + ts_data->prop.max_x = 1152;
> > + ts_data->prop.max_y = 1920;
> > + input_abs_set_max(ts_data->input_dev,
> > + ABS_MT_POSITION_X, ts_data->prop.max_x);
> > + input_abs_set_max(ts_data->input_dev,
> > + ABS_MT_POSITION_Y, ts_data->prop.max_y);
> > + }
> > +
> > + input_mt_init_slots(ts_data->input_dev, ts_data->pdata->max_touch_num,
> > + INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
>
> This mat fail so please handle errors here too.
>
Acknowledged.
> > +
> > + ret = input_register_device(ts_data->input_dev);
> > + if (ret < 0) {
> > + dev_err(&ts_data->client->dev,
> > + "Input device registration failed\n");
> > + return ret;
> > + }
> > +
> > + return ret;
>
> return 0;
>
Acknowledged.
> > +}
> > +
> > +static int hyn_probe(struct i2c_client *client)
> > +{
> > + struct hynitron_ts_data *ts_data;
> > + int ret;
>
> Call this variable "error" please.
>
Will do.
> > +
> > + ts_data = devm_kzalloc(&client->dev, sizeof(*ts_data), GFP_KERNEL);
> > + if (!ts_data)
> > + return -ENOMEM;
> > +
> > + ts_data->client = client;
> > + ts_data->dev = &client->dev;
> > + i2c_set_clientdata(client, ts_data);
> > +
> > + ts_data->reset_gpio = devm_gpiod_get(&client->dev,
> > + "reset", GPIOD_OUT_LOW);
>
> I've become fond of:
>
> error = PTR_ERR_OR_ZERO(ts_data->reset_gpio);
>
Okay, I'll do that.
> > + if (IS_ERR(ts_data->reset_gpio)) {
> > + ret = PTR_ERR(ts_data->reset_gpio);
> > + dev_err(&client->dev, "request reset gpio failed: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + ts_data->pdata = of_device_get_match_data(&client->dev);
> > + if (!ts_data->pdata)
> > + return -EINVAL;
> > +
> > + hyn_reset_proc(client, 60);
> > +
> > + ret = ts_data->pdata->bootloader_enter(client);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = ts_data->pdata->init_input(client);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = ts_data->pdata->firmware_info(client);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> > + hyn_interrupt_handler,
> > + IRQF_ONESHOT,
> > + "Hynitron Touch Int", client);
> > + if (ret < 0) {
> > + dev_err(&client->dev, "failed to request IRQ\n");
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static const struct hynitron_ts_platform_data cst3xx_data = {
> > + .max_touch_num = 5,
> > + .ic_chkcode = 0xcaca0000,
> > + .firmware_info = &cst3xx_firmware_info,
> > + .bootloader_enter = &cst3xx_bootloader_enter,
> > + .init_input = &cst3xx_input_dev_int,
> > + .report_touch = &cst3xx_touch_report,
> > +};
> > +
> > +static const struct i2c_device_id hyn_tpd_id[] = {
> > + { .name = "hynitron_ts", 0 },
> > + { /* sentinel */ },
> > +};
> > +MODULE_DEVICE_TABLE(i2c, hyn_tpd_id);
> > +
> > +static const struct of_device_id hyn_dt_match[] = {
> > + { .compatible = "hynitron,cst3xx", .data = &cst3xx_data },
> > + { /* sentinel */ },
> > +};
> > +MODULE_DEVICE_TABLE(of, hyn_dt_match);
> > +
> > +static struct i2c_driver hynitron_i2c_driver = {
> > + .driver = {
> > + .name = "Hynitron-TS",
> > + .of_match_table = of_match_ptr(hyn_dt_match),
> > + .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> > + },
> > + .id_table = hyn_tpd_id,
> > + .probe_new = hyn_probe,
> > +};
> > +
> > +module_i2c_driver(hynitron_i2c_driver);
> > +
> > +MODULE_AUTHOR("Chris Morgan");
> > +MODULE_DESCRIPTION("Hynitron Touchscreen Driver");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.25.1
> >
>
> Thanks.
Thank you for your input. I'll make the requested changes and resubmit.
>
> --
> Dmitry
