Message-ID: <20151014065847.GH20406@dtor-ws>
Date:	Tue, 13 Oct 2015 23:58:47 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Irina Tirdea <irina.tirdea@...el.com>
Cc:	Bastien Nocera <hadess@...ess.net>,
	Aleksei Mamlin <mamlinav@...il.com>,
	linux-input@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
	Octavian Purdila <octavian.purdila@...el.com>,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v7 3/9] Input: goodix - write configuration data to device

On Thu, Oct 08, 2015 at 01:19:29PM +0300, Irina Tirdea wrote:
> Goodix devices can be configured by writing custom data to the device at
> init. The configuration data is read with request_firmware from
> "goodix_<id>_cfg.bin", where <id> is the product id read from the device
> (e.g.: goodix_911_cfg.bin for Goodix GT911, goodix_9271_cfg.bin for
> GT9271).
> 
> The configuration information has a specific format described in the Goodix
> datasheet. It includes X/Y resolution, maximum supported touch points,
> interrupt flags, various sensitivity factors and settings for advanced
> features (like gesture recognition).
> 
> Before writing the firmware, it is necessary to reset the device. If
> the device ACPI/DT information does not declare gpio pins (needed for
> reset), writing the firmware will not be available for these devices.
> 
> This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> driver gt9xx.c for Android (publicly available in Android kernel
> trees for various devices).
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@...el.com>
> Signed-off-by: Irina Tirdea <irina.tirdea@...el.com>
> ---
>  drivers/input/touchscreen/goodix.c | 229 +++++++++++++++++++++++++++++++------
>  1 file changed, 196 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> index 916198d..37035fb 100644
> --- a/drivers/input/touchscreen/goodix.c
> +++ b/drivers/input/touchscreen/goodix.c
> @@ -16,6 +16,7 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/dmi.h>
> +#include <linux/firmware.h>
>  #include <linux/gpio.h>
>  #include <linux/i2c.h>
>  #include <linux/input.h>
> @@ -40,6 +41,9 @@ struct goodix_ts_data {
>  	int cfg_len;
>  	struct gpio_desc *gpiod_int;
>  	struct gpio_desc *gpiod_rst;
> +	u16 id;
> +	u16 version;
> +	char *cfg_name;
>  };
>  
>  #define GOODIX_GPIO_INT_NAME		"irq"
> @@ -159,6 +163,39 @@ static int goodix_i2c_read(struct i2c_client *client,
>  	return ret < 0 ? ret : (ret != ARRAY_SIZE(msgs) ? -EIO : 0);
>  }
>  
> +/**
> + * goodix_i2c_write - write data to a register of the i2c slave device.
> + *
> + * @client: i2c device.
> + * @reg: the register to write to.
> + * @buf: raw data buffer to write.
> + * @len: length of the buffer to write
> + */
> +static int goodix_i2c_write(struct i2c_client *client, u16 reg, const u8 *buf,
> +			    unsigned len)
> +{
> +	u8 *addr_buf;
> +	struct i2c_msg msg;
> +	int ret;
> +
> +	addr_buf = kmalloc(len + 2, GFP_KERNEL);
> +	if (!addr_buf)
> +		return -ENOMEM;
> +
> +	addr_buf[0] = reg >> 8;
> +	addr_buf[1] = reg & 0xFF;
> +	memcpy(&addr_buf[2], buf, len);
> +
> +	msg.flags = 0;
> +	msg.addr = client->addr;
> +	msg.buf = addr_buf;
> +	msg.len = len + 2;
> +
> +	ret = i2c_transfer(client->adapter, &msg, 1);
> +	kfree(addr_buf);
> +	return ret < 0 ? ret : (ret != 1 ? -EIO : 0);
> +}
> +
>  static int goodix_get_cfg_len(u16 id)
>  {
>  	switch (id) {
> @@ -278,6 +315,73 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +/**
> + * goodix_check_cfg - Checks if config fw is valid
> + *
> + * @ts: goodix_ts_data pointer
> + * @cfg: firmware config data
> + */
> +static int goodix_check_cfg(struct goodix_ts_data *ts,
> +			    const struct firmware *cfg)
> +{
> +	int i, raw_cfg_len;
> +	u8 check_sum = 0;
> +
> +	if (cfg->size > GOODIX_CONFIG_MAX_LENGTH) {
> +		dev_err(&ts->client->dev,
> +			"The length of the config fw is not correct");
> +		return -EINVAL;
> +	}
> +
> +	raw_cfg_len = cfg->size - 2;
> +	for (i = 0; i < raw_cfg_len; i++)
> +		check_sum += cfg->data[i];
> +	check_sum = (~check_sum) + 1;
> +	if (check_sum != cfg->data[raw_cfg_len]) {
> +		dev_err(&ts->client->dev,
> +			"The checksum of the config fw is not correct");
> +		return -EINVAL;
> +	}
> +
> +	if (cfg->data[raw_cfg_len + 1] != 1) {
> +		dev_err(&ts->client->dev,
> +			"Config fw must have Config_Fresh register set");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * goodix_send_cfg - Write fw config to device
> + *
> + * @ts: goodix_ts_data pointer
> + * @cfg: config firmware to write to device
> + */
> +static int goodix_send_cfg(struct goodix_ts_data *ts,
> +			   const struct firmware *cfg)
> +{
> +	int error;
> +
> +	error = goodix_check_cfg(ts, cfg);
> +	if (error)
> +		return error;
> +
> +	error = goodix_i2c_write(ts->client, GOODIX_REG_CONFIG_DATA, cfg->data,
> +				 cfg->size);
> +	if (error) {
> +		dev_err(&ts->client->dev, "Failed to write config data: %d",
> +			error);
> +		return error;
> +	}
> +	dev_dbg(&ts->client->dev, "Config sent successfully.");
> +
> +	/* Let the firmware reconfigure itself, so sleep for 10ms */
> +	usleep_range(10000, 11000);
> +
> +	return 0;
> +}
> +
>  static int goodix_int_sync(struct goodix_ts_data *ts)
>  {
>  	int error;
> @@ -432,30 +536,29 @@ static void goodix_read_config(struct goodix_ts_data *ts)
>  /**
>   * goodix_read_version - Read goodix touchscreen version
>   *
> - * @client: the i2c client
> - * @version: output buffer containing the version on success
> - * @id: output buffer containing the id on success
> + * @ts: our goodix_ts_data pointer
>   */
> -static int goodix_read_version(struct i2c_client *client, u16 *version, u16 *id)
> +static int goodix_read_version(struct goodix_ts_data *ts)
>  {
>  	int error;
>  	u8 buf[6];
>  	char id_str[5];
>  
> -	error = goodix_i2c_read(client, GOODIX_REG_ID, buf, sizeof(buf));
> +	error = goodix_i2c_read(ts->client, GOODIX_REG_ID, buf, sizeof(buf));
>  	if (error) {
> -		dev_err(&client->dev, "read version failed: %d\n", error);
> +		dev_err(&ts->client->dev, "read version failed: %d\n", error);
>  		return error;
>  	}
>  
>  	memcpy(id_str, buf, 4);
>  	id_str[4] = 0;
> -	if (kstrtou16(id_str, 10, id))
> -		*id = 0x1001;
> +	if (kstrtou16(id_str, 10, &ts->id))
> +		ts->id = 0x1001;
>  
> -	*version = get_unaligned_le16(&buf[4]);
> +	ts->version = get_unaligned_le16(&buf[4]);
>  
> -	dev_info(&client->dev, "ID %d, version: %04x\n", *id, *version);
> +	dev_info(&ts->client->dev, "ID %d, version: %04x\n", ts->id,
> +		 ts->version);
>  
>  	return 0;
>  }
> @@ -489,13 +592,10 @@ static int goodix_i2c_test(struct i2c_client *client)
>   * goodix_request_input_dev - Allocate, populate and register the input device
>   *
>   * @ts: our goodix_ts_data pointer
> - * @version: device firmware version
> - * @id: device ID
>   *
>   * Must be called during probe
>   */
> -static int goodix_request_input_dev(struct goodix_ts_data *ts, u16 version,
> -				    u16 id)
> +static int goodix_request_input_dev(struct goodix_ts_data *ts)
>  {
>  	int error;
>  
> @@ -519,8 +619,8 @@ static int goodix_request_input_dev(struct goodix_ts_data *ts, u16 version,
>  	ts->input_dev->phys = "input/ts";
>  	ts->input_dev->id.bustype = BUS_I2C;
>  	ts->input_dev->id.vendor = 0x0416;
> -	ts->input_dev->id.product = id;
> -	ts->input_dev->id.version = version;
> +	ts->input_dev->id.product = ts->id;
> +	ts->input_dev->id.version = ts->version;
>  
>  	error = input_register_device(ts->input_dev);
>  	if (error) {
> @@ -532,13 +632,70 @@ static int goodix_request_input_dev(struct goodix_ts_data *ts, u16 version,
>  	return 0;
>  }
>  
> +/**
> + * goodix_configure_dev - Finish device initialization
> + *
> + * @ts: our goodix_ts_data pointer
> + *
> + * Must be called from probe to finish initialization of the device.
> + * Contains the common initialization code for both devices that
> + * declare gpio pins and devices that do not. It is either called
> + * directly from probe or from request_firmware_wait callback.
> + */
> +static int goodix_configure_dev(struct goodix_ts_data *ts)
> +{
> +	int error;
> +	unsigned long irq_flags;
> +
> +	goodix_read_config(ts);
> +
> +	error = goodix_request_input_dev(ts);
> +	if (error)
> +		return error;
> +
> +	irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
> +	error = devm_request_threaded_irq(&ts->client->dev, ts->client->irq,
> +					  NULL, goodix_ts_irq_handler,
> +					  irq_flags, ts->client->name, ts);
> +	if (error) {
> +		dev_err(&ts->client->dev, "request IRQ failed: %d\n", error);
> +		return error;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * goodix_config_cb - Callback to finish device init
> + *
> + * @ts: our goodix_ts_data pointer
> + *
> + * request_firmware_wait callback that finishes
> + * initialization of the device.
> + */
> +static void goodix_config_cb(const struct firmware *cfg, void *ctx)
> +{
> +	struct goodix_ts_data *ts = (struct goodix_ts_data *)ctx;
> +	int error;
> +
> +	if (cfg) {
> +		/* send device configuration to the firmware */
> +		error = goodix_send_cfg(ts, cfg);
> +		if (error)
> +			goto err_release_cfg;
> +	}
> +	goodix_configure_dev(ts);
> +
> +err_release_cfg:
> +	kfree(ts->cfg_name);
> +	release_firmware(cfg);

You need to use completion to signal remove() (and also probably
suspend/resume in the subsequent patches) that you are done handling
config, otherwise if you do bind/unbind via sysfs in a tight loop you
will observe a nice crash.

Thanks.

> +}
> +
>  static int goodix_ts_probe(struct i2c_client *client,
>  			   const struct i2c_device_id *id)
>  {
>  	struct goodix_ts_data *ts;
> -	unsigned long irq_flags;
>  	int error;
> -	u16 version_info, id_info;
>  
>  	dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);
>  
> @@ -573,30 +730,36 @@ static int goodix_ts_probe(struct i2c_client *client,
>  		return error;
>  	}
>  
> -	error = goodix_read_version(client, &version_info, &id_info);
> +	error = goodix_read_version(ts);
>  	if (error) {
>  		dev_err(&client->dev, "Read version failed.\n");
>  		return error;
>  	}
>  
> -	ts->cfg_len = goodix_get_cfg_len(id_info);
> -
> -	goodix_read_config(ts);
> +	ts->cfg_len = goodix_get_cfg_len(ts->id);
>  
> -	error = goodix_request_input_dev(ts, version_info, id_info);
> -	if (error)
> -		return error;
> +	if (ts->gpiod_int && ts->gpiod_rst) {
> +		/* update device config */
> +		ts->cfg_name = kasprintf(GFP_KERNEL, "goodix_%d_cfg.bin",
> +					 ts->id);
> +		if (!ts->cfg_name)
> +			return -ENOMEM;
> +
> +		error = request_firmware_nowait(THIS_MODULE, true, ts->cfg_name,
> +						&client->dev, GFP_KERNEL, ts,
> +						goodix_config_cb);
> +		if (error) {
> +			dev_err(&client->dev,
> +				"Failed to invoke firmware loader: %d\n",
> +				error);
> +			kfree(ts->cfg_name);
> +			return error;
> +		}
>  
> -	irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
> -	error = devm_request_threaded_irq(&ts->client->dev, client->irq,
> -					  NULL, goodix_ts_irq_handler,
> -					  irq_flags, client->name, ts);
> -	if (error) {
> -		dev_err(&client->dev, "request IRQ failed: %d\n", error);
> -		return error;
> +		return 0;
>  	}
>  
> -	return 0;
> +	return goodix_configure_dev(ts);
>  }
>  
>  static int goodix_ts_remove(struct i2c_client *client)
> -- 
> 1.9.1
> 

-- 
Dmitry
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