Hi Jeffrey,

On Wed, Jan 13, 2016 at 03:49:12PM +0800, Jeffrey Lin wrote:

This patch is porting Raydium I2C touch driver. Developer can enable raydium touch driver by modifying define
"CONFIG_TOUCHSCREEN_RM_TS".

Doing a quick pass over the driver to give you some more feedback for
the next version. 

I do not see this being used in the driver (and if you needed something
like that you probably would need get_unaligned_le16() or
get_unaligned-be16()).

+}
+*/
+static s32 rm31100_ts_write_reg_u8(struct i2c_client *client, u8 reg, u8 val)

Why s32? Just return "int".

+{
+	s32 data;
+
+	data = i2c_smbus_write_byte_data(client, reg, val);
+	if (data < 0)
+		dev_err(&client->dev, "error %d in writing reg 0x%x\n",
+						 data, reg);
+
+	return data;
+}
+
+static s32 rm31100_ts_read_reg_u8(struct i2c_client *client, u8 reg)

Same here.

+{
+	s32 data;
+
+	data = i2c_smbus_read_byte_data(client, reg);
+	if (data < 0)
+		dev_err(&client->dev, "error %d in reading reg 0x%x\n",
+						 data, reg);
+
+	return data;
+}
+
+static int rm31100_ts_read(struct i2c_client *client, u8 reg, u8 *buf, int num)
+{
+	struct i2c_msg xfer_msg[2];
+
+	xfer_msg[0].addr = client->addr;
+	xfer_msg[0].len = 1;
+	xfer_msg[0].flags = 0;
+	xfer_msg[0].buf = &reg;
+
+	xfer_msg[1].addr = client->addr;
+	xfer_msg[1].len = num;
+	xfer_msg[1].flags = I2C_M_RD;
+	xfer_msg[1].buf = buf;
+
+	return i2c_transfer(client->adapter, xfer_msg, 2);

ARRAY_SIZE(xfer_msg).

+}
+
+static int rm31100_ts_write(struct i2c_client *client, u8 *buf, int num)
+{
+	struct i2c_msg xfer_msg[1];
+
+	xfer_msg[0].addr = client->addr;
+	xfer_msg[0].len = num;
+	xfer_msg[0].flags = 0;
+	xfer_msg[0].buf = buf;
+
+	return i2c_transfer(client->adapter, xfer_msg, 1);
+}
+
+static ssize_t rm_fw_version_show(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct rm31100_ts *info = dev_get_drvdata(dev);
+	return sprintf(buf, "Release V 0x%02X, Test V 0x%02X\n",
+		info.u8_version,
+		info.u8_sub_version);
+}

We should have 1 value per sysfs attribute, so please split it on 2:
firmware version and test or subversion and output simply number. This
way it is much easier to process them in scripts.

+
+static DEVICE_ATTR(fw_version, S_IRUGO, rm_fw_version_show, NULL);
+
+static struct attribute *rm_ts_attributes[] = {
+	&dev_attr_fw_version.attr,
+	NULL
+};
+
+static const struct attribute_group rm_ts_attr_group = {
+	.attrs = rm_ts_attributes,
+};
+
+static void report_data(struct rm31100_ts *dev, u16 x, u16 y,
+	u8 pressure, u8 id)
+{
+	struct input_dev *input_dev = dev->input;
+	if (dev->pdata->swap_xy)
+		swap(x, y);
+
+	input_mt_slot(input_dev, id);
+	input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, true);
+	input_report_abs(input_dev, ABS_MT_POSITION_X, x);
+	input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
+	input_report_abs(input_dev, ABS_MT_PRESSURE, pressure);
+	input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, dev->dd->finger_size);
+}
+
+static void process_rm31100_data(struct rm31100_ts *ts)
+{
+	u8 id, pressure, touches, i;
+	u16 x, y;
+
+	touches = ts->touch_data[ts->dd->touch_index];
+
+	if (touches > 0) {
+		for (i = 0; i < touches; i++) {
+			id = ts->touch_data[i * ts->dd->touch_bytes +
+				ts->dd->id_index];
+			pressure = ts->touch_data[i * ts->dd->touch_bytes +
+				ts->dd->z_index];
+			x = get_unaligned_le16(&(ts->touch_data[i *
+				ts->dd->touch_bytes + ts->dd->x_index]));
+			y = get_unaligned_le16(&(ts->touch_data[i *
+				ts->dd->touch_bytes + ts->dd->y_index]));
+			report_data(ts, x, y, pressure, id);
+		}
+	} else
+		input_mt_sync(ts->input);
+
+	ts->prev_touches = touches;

Why do you need prev_touches? I do not see you reporting touch lifting
the surface, do you need to also pass INPUT_MT_DROP_UNUSED flag to
input_mt_init_slots()? 

+
+	input_mt_report_pointer_emulation(ts->input, true);
+	input_sync(ts->input);
+}
+
+static void rm31100_ts_xy_worker(struct rm31100_ts *work)
+{
+	int rc;
+	struct rm31100_ts *ts = work;
+
+	mutex_lock(&ts->access_lock);

Why do we need to take the lock here? What are we trying to protect? The
interrupt thread is not reentrable.

+	/* read data from DATA_REG */
+	rc = rm31100_ts_read(ts->client, ts->dd->data_reg, ts->touch_data,
+	ts->dd->data_size);
+
+	if (rc < 0) {
+		dev_err(&ts->client->dev, "read failed\n");
+		goto schedule;
+	}
+
+	if (ts->touch_data[ts->dd->touch_index] == INVALID_DATA)
+		goto schedule;
+
+	/* write to STATUS_REG to release lock */
+	rc = rm31100_ts_write_reg_u8(ts->client,
+		ts->dd->status_reg, ts->dd->update_data);
+	if (rc < 0) {
+		dev_err(&ts->client->dev, "write failed, try once more\n");
+
+		rc = rm31100_ts_write_reg_u8(ts->client,
+			ts->dd->status_reg, ts->dd->update_data);
+		if (rc < 0)
+			dev_err(&ts->client->dev, "write failed, exiting\n");
+	}
+
+	process_rm31100_data(ts);
+schedule:
+	mutex_unlock(&ts->access_lock);
+}
+
+static irqreturn_t rm31100_ts_irq(int irq, void *dev_id)
+{
+	struct rm31100_ts *ts = dev_id;
+
+	rm31100_ts_xy_worker(ts);
+	return IRQ_HANDLED;

I'd probably merge rm31100_ts_xy_worker() into rm31100_ts_irq().

+}
+
+static int rm_ts_power_on(struct rm31100_ts *ts)
+{
+	int error;
+
+	/*
+	 * If we do not have reset gpio assume platform firmware
+	 * controls regulators and does power them on for us.
+	 */
+	if (IS_ERR_OR_NULL(ts->resout_gpio))
+		return 0;
+
+	gpiod_set_value_cansleep(ts->resout_gpio, 1);
+
+	error = regulator_enable(ts->avdd);
+	if (error) {
+		dev_err(&ts->client->dev,
+			"failed to enable avdd regulator: %d\n",
+			error);
+		goto release_reset_gpio;
+	}
+
+	error = regulator_enable(ts->dvdd);
+	if (error) {
+		dev_err(&ts->client->dev,
+			"failed to enable dvdd regulator: %d\n",
+			error);
+		regulator_disable(ts->dvdd);
+		goto release_reset_gpio;
+	}
+
+release_reset_gpio:
+	gpiod_set_value_cansleep(ts->resout_gpio, 0);
+	if (error)
+		return error;
+
+	msleep(20);
+
+	return 0;
+}
+
+static void rm_ts_power_off(void *_data)
+{
+	struct rm31100_ts *data = _data;
+
+	if (!IS_ERR_OR_NULL(data->resout_gpio)) {
+		/*
+		 * Activate reset gpio to prevent leakage through the
+		 * pin once we shut off power to the controller.
+		 */
+		gpiod_set_value_cansleep(data->resout_gpio, 1);
+		regulator_disable(data->avdd);
+		regulator_disable(data->dvdd);
+	}
+}
+
+static int rm31100_ts_init_ts(struct i2c_client *client, struct rm31100_ts *ts)
+{
+	/*struct input_dev *input_device;*/
+	/*int rc = 0;*/
+
+	ts->dd = &devices[ts->device_id];
+
+	if (!ts->pdata->nfingers) {
+		dev_err(&client->dev, "Touches information not specified\n");
+		return -EINVAL;
+	}
+
+	if (ts->device_id == rm3110x) {
+		if (ts->pdata->nfingers > 2) {
+			dev_err(&client->dev, "Touches >=1 & <= 2\n");
+			return -EINVAL;
+		}
+		ts->dd->data_size = ts->dd->touch_bytes;
+		ts->dd->touch_index = 0x0;
+	} else if (ts->device_id == rm31100) {
+		if (ts->pdata->nfingers > 10) {
+			dev_err(&client->dev, "Touches >=1 & <= 10\n");
+			return -EINVAL;
+		}
+		ts->dd->data_size = ts->pdata->nfingers * ts->dd->touch_bytes +
+						ts->dd->touch_meta_data;
+		ts->dd->touch_index = 0x0;
+	}
+	/* w001 */
+	else {
+		ts->dd->data_size = ts->pdata->nfingers * ts->dd->touch_bytes +
+		ts->dd->touch_meta_data;
+		ts->dd->touch_index = 0x0;
+	}
+
+	ts->touch_data = kzalloc(ts->dd->data_size, GFP_KERNEL);
+	if (!ts->touch_data) {
+		pr_err("%s: Unable to allocate memory\n", __func__);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static int __maybe_unused rm31100_ts_suspend(struct device *dev)
+{
+	struct rm31100_ts *ts = dev_get_drvdata(dev);
+	int rc = 0;
+
+	if (device_may_wakeup(dev)) {
+		/* mark suspend flag */
+		ts->is_suspended = true;
+		enable_irq_wake(ts->pen_irq);
+	}
+
+	disable_irq(ts->pen_irq);
+
+	gpiod_set_value_cansleep(ts->resout_gpio, 0);

Why do we set it as "inactive" only to set it to "active" in
rm_ts_power_off()?

+
+	rm_ts_power_off(ts);
+
+	return 0;
+}
+
+static int __maybe_unused rm31100_ts_resume(struct device *dev)
+{
+	struct rm31100_ts *ts = dev_get_drvdata(dev);
+
+	int rc = 0;
+
+	if (device_may_wakeup(dev)) {
+		disable_irq_wake(ts->pen_irq);
+
+		ts->is_suspended = false;
+
+		if (ts->int_pending == true)
+			ts->int_pending = false;

Why do you need this?

+	} else {
+		rc = rm_ts_power_on(ts);
+		if (rc) {
+			dev_err(dev, "unable to resume\n");
+			return rc;
+		}
+
+		enable_irq(ts->pen_irq);
+
+		/* Clear the status register of the TS controller */
+		rc = rm31100_ts_write_reg_u8(ts->client,
+			ts->dd->status_reg, ts->dd->update_data);
+		if (rc < 0) {
+			dev_err(&ts->client->dev,
+				"write failed, try once more\n");
+
+			rc = rm31100_ts_write_reg_u8(ts->client,
+				ts->dd->status_reg,
+				ts->dd->update_data);
+			if (rc < 0)
+				dev_err(&ts->client->dev,
+					"write failed, exiting\n");
+		}
+	}
+
+	return 0;
+}
+
+static void rm_ts_remove_sysfs_group(void *_data)
+{
+	struct rm31100_ts *ts = _data;
+
+	sysfs_remove_group(&ts->client->dev.kobj, &rm_ts_attr_group);
+}
+
+static SIMPLE_DEV_PM_OPS(rm31100_ts_pm_ops,
+			 rm31100_ts_suspend, rm31100_ts_resume);
+
+static int rm_input_dev_create(struct rm31100_ts *ts)
+{
+	struct input_dev *input_device;
+	int rc = 0;
+	ts->prev_touches = 0;
+
+	input_device = input_allocate_device();
+	if (!input_device) {
+		rc = -ENOMEM;
+		goto error_alloc_dev;
+	}
+	ts->input = input_device;
+
+	input_device->name = "raydium_ts";
+	input_device->id.bustype = BUS_I2C;
+	input_device->dev.parent = &ts->client->dev;
+	input_set_drvdata(input_device, ts);
+
+	__set_bit(BTN_TOUCH, input_device->keybit);
+	__set_bit(EV_ABS, input_device->evbit);
+	__set_bit(EV_KEY, input_device->evbit);
+
+	/* For single touch */
+	input_set_abs_params(input_device, ABS_X,
+			     ts->pdata->dis_min_x, ts->pdata->dis_max_x, 0, 0);
+	input_set_abs_params(input_device, ABS_Y,
+			     ts->pdata->dis_min_x, ts->pdata->dis_max_y, 0, 0);
+	input_set_abs_params(input_device, ABS_PRESSURE,
+			     0, 255, 0, 0);
+	input_abs_set_res(input_device, ABS_X, ts->pdata->res_x);
+	input_abs_set_res(input_device, ABS_Y, ts->pdata->res_y);
+
+	/* Multitouch input params setup */
+	rc = input_mt_init_slots(input_device,
+		MAX_REPORT_TOUCHED_POINTS, INPUT_MT_DIRECT);
+	if (rc)
+		goto error_unreg_device;
+
+	input_set_abs_params(input_device, ABS_MT_POSITION_X,
+		ts->pdata->dis_min_x, ts->pdata->dis_max_x, 0, 0);
+	input_set_abs_params(input_device, ABS_MT_POSITION_Y,
+		ts->pdata->dis_min_y, ts->pdata->dis_max_y, 0, 0);
+	input_set_abs_params(input_device, ABS_MT_PRESSURE,
+		0, 0xFF, 0, 0);
+	input_set_abs_params(input_device, ABS_MT_TOUCH_MAJOR,
+		0, 0xFF, 0, 0);
+	input_abs_set_res(input_device, ABS_MT_POSITION_X, ts->pdata->res_x);
+	input_abs_set_res(input_device, ABS_MT_POSITION_Y, ts->pdata->res_y);
+
+	rc = input_register_device(input_device);
+	if (rc)
+		goto error_unreg_device;
+
+	return 0;
+
+error_unreg_device:
+	input_free_device(input_device);
+error_alloc_dev:
+	ts->input = NULL;
+	return rc;
+}
+
+static int rm31100_initialize(struct i2c_client *client)
+{
+	struct rm31100_ts *ts = i2c_get_clientdata(client);
+	int rc = 0, temp_reg;
+
+	/* read one byte to make sure i2c device exists */
+	if (ts->device_id == rm3110x)
+		temp_reg = 0x01;
+	else if (ts->device_id == rm31100)
+		temp_reg = 0x00;
+	else
+		temp_reg = 0x05;
+
+	rc = rm31100_ts_read_reg_u8(client, temp_reg);
+	if (rc < 0) {
+		dev_err(&client->dev, "i2c sanity check failed\n");
+		return rc;
+	}
+
+	rc = rm31100_ts_init_ts(client, ts);
+	if (rc < 0) {
+		dev_err(&client->dev, "rm31100_ts init failed\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static int rm31100_ts_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct rm31100_ts *ts;
+	struct rm3110x_ts_platform_data *pdata = client->dev.platform_data;
+	int rc;
+	union i2c_smbus_data dummy;
+
+	ts = devm_kzalloc(&client->dev, sizeof(struct rm31100_ts), GFP_KERNEL);
+	if (!ts) {
+		dev_err(&client->dev, "Failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	if (!i2c_check_functionality(client->adapter,
+		I2C_FUNC_SMBUS_READ_WORD_DATA)) {
+		dev_err(&client->dev, "I2C functionality not supported\n");
+		rc = -EIO;
+		goto error_touch_data_alloc;
+	}
+
+	ts->client = client;
+	ts->pdata = pdata;
+	i2c_set_clientdata(client, ts);
+	ts->device_id = id->driver_data;
+
+	ts->is_suspended = false;
+	ts->int_pending = false;
+
+	mutex_init(&ts->access_lock);
+
+	ts->avdd = devm_regulator_get(&client->dev, "avdd");
+	if (IS_ERR(ts->avdd)) {
+		rc = PTR_ERR(ts->avdd);
+		if (rc != -EPROBE_DEFER)
+			dev_err(&client->dev,
+				"Failed to get 'avdd' regulator: %d\n",
+				rc);
+		return rc;
+	}
+
+	ts->dvdd = devm_regulator_get(&client->dev, "dvdd");
+	if (IS_ERR(ts->dvdd)) {
+		rc = PTR_ERR(ts->dvdd);
+		if (rc != -EPROBE_DEFER)
+			dev_err(&client->dev,
+				"Failed to get 'dvdd' regulator: %d\n",
+				rc);
+		return rc;
+	}
+
+	ts->resout_gpio = devm_gpiod_get(&client->dev, "rm31100_resout_gpio");
+	if (IS_ERR(ts->resout_gpio)) {
+		rc = PTR_ERR(ts->resout_gpio);
+
+		/*
+		 * On Chromebooks vendors like to source touch panels from
+		 * different vendors, but they are connected to the same
+		 * regulators/GPIO pin. The drivers also use asynchronous
+		 * probing, which means that more than one driver will
+		 * attempt to claim the reset line. If we find it busy,
+		 * let's try again later.
+		 */
+		if (rc == -EBUSY) {
+			dev_info(&client->dev,
+				 "reset gpio is busy, deferring probe\n");
+			return -EPROBE_DEFER;
+		}

This is Chrome OS specific and is not needed for mainline. Simply do:


	ts->resout_gpio = devm_gpiod_get_optional(&client->dev,
						  "resout", GPIOF_OUT_LOW);
	if (IS_ERR(ts->resout_gpio)) {
		error = PTR_ERR(ts->resout_gpio);
		if (error != -EPROBE_DEFER)
			dev_err(...);
		return error;
	}

+
+		if (rc == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		if (rc != -ENOENT && rc != -ENOSYS) {
+			dev_err(&client->dev,
+				"failed to get reset gpio: %d\n",
+				rc);
+			return rc;
+		}
+
+	} else {
+		rc = gpiod_direction_output(ts->resout_gpio, 0);
+		if (rc) {
+			dev_err(&client->dev,
+				"failed to configure reset gpio as output: %d\n",
+				rc);
+			return rc;
+		}
+	}
+
+	rc = rm_ts_power_on(ts);
+	if (rc)
+		return rc;
+
+	rc = devm_add_action(&client->dev, rm_ts_power_off, ts);
+	if (rc) {
+		dev_err(&client->dev,
+			"failed to install power off action: %d\n", rc);
+		rm_ts_power_off(ts);
+		return rc;
+	}
+
+	/* Make sure there is something at this address */
+	if (i2c_smbus_xfer(client->adapter, client->addr, 0,
+		I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &dummy) < 0)
+		return -ENODEV;
+
+	rc = rm31100_initialize(client);
+	if (rc < 0) {
+		dev_err(&client->dev, "probe failed! unbind device.\n");
+		return rc;
+	}
+
+	rc = rm_input_dev_create(ts);
+	if (rc) {
+		dev_err(&client->dev, "%s crated failed, %d\n", __func__, err);
+		return rc;
+	}
+
+	rc = devm_request_threaded_irq(&client->dev, ts->pen_irq,
+					NULL, rm31100_ts_irq,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					client->name, ts);
+	if (rc) {
+		dev_err(&client->dev, "Failed to register interrupt\n");
+		return rc;
+	}
+
+	device_set_wakeup_enable(&client->dev, false);

Why? Let platform code decide, drop this line.

+
+	rc = sysfs_create_group(&client->dev.kobj, &rm_ts_attr_group);
+	if (rc) {
+		dev_err(&client->dev, "failed to create sysfs attributes: %d\n",
+			rc);
+		return rc;
+	}
+
+	rc = devm_add_action(&client->dev,
+				rm_ts_remove_sysfs_group, ts);
+	if (rc) {
+		rm_ts_remove_sysfs_group(ts);
+		dev_err(&client->dev,
+			"Failed to add sysfs cleanup action: %d\n",
+			rc);
+		return rc;
+	}
+	return 0;
+
+error_touch_data_alloc:
+	kfree(ts);
+	return rc;

You can't kfree() data allocated with devm_kzalloc(), nor shoudl you -
it will deallocate automatically.

+}
+
+static int rm31100_ts_remove(struct i2c_client *client)
+{
+	struct rm31100_ts *ts = i2c_get_clientdata(client);
+
+	device_init_wakeup(&client->dev, 0);
+	free_irq(ts->pen_irq, ts);

No, it was requested with devm_*

+
+	if (ts->resout_gpio >= 0)
+		gpiod_set_value_cansleep(ts->resout_gpio, 0);

Why do we do this here?

+
+	input_unregister_device(ts->input);

Manually-managed and devm-managed resources do not play well with each
other, you better switch all of them to devm, including input device.

+
+	/*mutex_destroy(&ts->sus_lock); JL remove*/

Why i it still here if it is marked for removal?

+	mutex_destroy(&ts->access_lock);
+
+	rm_ts_power_off(ts);
+
+	kfree(ts->touch_data);
+	kfree(ts);
+
+	return 0;
+}
+
+static const struct i2c_device_id rm31100_ts_id[] = {
+	{"RM31100", rm31100},
+	{"RM3110x", rm3110x},

Instead of using a constant and then doing if/else if/else to reference
your devices[] array why don't you attach instance of rm31100_ts_data
directly?

+	{}
+};
+MODULE_DEVICE_TABLE(i2c, rm31100_ts_id);
+
+
+static struct i2c_driver rm31100_ts_driver = {
+	.driver = {
+		.name = "raydium_ts",
+		.owner = THIS_MODULE,

No need to set owner explicitly.

+#ifdef CONFIG_PM
+		.pm = &rm31100_ts_pm_ops,
+#endif

No need for #ifdef here.

+	},
+	.probe = rm31100_ts_probe,
+	.remove = rm31100_ts_remove,
+	.id_table = rm31100_ts_id,
+};
+
+static int __init rm31100_ts_init(void)
+{
+	int rc;
+	int rc2;
+
+	rc = i2c_add_driver(&rm31100_ts_driver);
+
+	rc2 = driver_create_file(&rm31100_ts_driver.driver,
+		&driver_attr_myAttr);

What is this for? I suspect you do not need this, so init/exit can be
folded into module_i2c_driver() macro.

+
+	return rc;
+}
+/* Making this as late init to avoid power fluctuations
+ * during LCD initialization.
+ */
+module_init(rm31100_ts_init);
+
+static void __exit rm31100_ts_exit(void)
+{
+	i2c_del_driver(&rm31100_ts_driver);
+}
+module_exit(rm31100_ts_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("rm31100-rm3110x touchscreen controller driver");
+MODULE_AUTHOR("Raydium");
+MODULE_ALIAS("platform:rm31100_ts");
-- 
2.1.2

Thanks.

-- 
Dmitry