On Fri, Feb 01, 2013 at 04:11:46PM +0800, Daniel Kurtz wrote:
> In some cases it is possible for a device to be in its bootloader at
> driver probe time. This is detected by the driver when probe() is called
> with an i2c_client which has one of the Atmel Bootloader i2c addresses.
>
> In this case, we should load enough driver functionality to still loading
> new firmware using:
> echo 1 > update_fw
>
> However, we must be very careful not to follow any code paths that would try
> to access the as-yet uninitialized object table or input device.
> In particular:
> 1) mxt_remove calls input_unregister_device on input_dev.
> 2) mxt_suspend/resume reads and writes from the object table.
> 3) Spurious or bootloader induced interrupts
>
> Signed-off-by: Benson Leung <ble...@chromium.org>
> Signed-off-by: Daniel Kurtz <djku...@chromium.org>
> ---
> drivers/input/touchscreen/atmel_mxt_ts.c | 51
> +++++++++++++++++++++++++-------
> 1 file changed, 40 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
> b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 9afc26e..6c2c712 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -324,6 +324,12 @@ static void mxt_dump_message(struct device *dev,
> message->reportid, 7, message->message);
> }
>
> +static bool mxt_in_bootloader(struct mxt_data *data)
> +{
> + struct i2c_client *client = data->client;
> + return (client->addr == MXT_BOOT_LOW || client->addr == MXT_BOOT_HIGH);
> +}
> +
> static int mxt_i2c_recv(struct i2c_client *client, u8 *buf, size_t count)
> {
> int ret;
> @@ -584,6 +590,9 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
> u8 reportid;
> bool update_input = false;
>
> + if (mxt_in_bootloader(data))
> + goto end;
> +
> do {
> if (mxt_read_message(data, &message)) {
> dev_err(dev, "Failed to read message\n");
> @@ -975,6 +984,9 @@ static int mxt_load_fw(struct device *dev, const char *fn)
> return ret;
> }
>
> + if (mxt_in_bootloader(data))
> + goto bootloader_ready;
> +
> /* Change to the bootloader mode */
> mxt_write_object(data, MXT_GEN_COMMAND_T6,
> MXT_COMMAND_RESET, MXT_BOOT_VALUE);
> @@ -986,6 +998,7 @@ static int mxt_load_fw(struct device *dev, const char *fn)
> else
> client->addr = MXT_BOOT_HIGH;
>
> +bootloader_ready:
> ret = mxt_check_bootloader(client, MXT_WAITING_BOOTLOAD_CMD);
> if (ret)
> goto out;
> @@ -1196,25 +1209,34 @@ static int __devinit mxt_probe(struct i2c_client
> *client,
>
> mxt_calc_resolution(data);
>
> - error = mxt_initialize(data);
> - if (error)
> - goto err_free_mem;
> + if (mxt_in_bootloader(data)) {
> + dev_info(&client->dev, "Device in bootloader at probe\n");
> + } else {
> + error = mxt_initialize(data);
> + if (error)
> + goto err_free_mem;
>
> - error = mxt_input_dev_create(data);
> - if (error)
> - goto err_free_object;
> + error = mxt_input_dev_create(data);
> + if (error)
> + goto err_free_object;
> + }
>
> error = request_threaded_irq(client->irq, NULL, mxt_interrupt,
> pdata->irqflags | IRQF_ONESHOT,
> client->name, data);
> if (error) {
> dev_err(&client->dev, "Failed to register interrupt\n");
> - goto err_unregister_device;
> + if (mxt_in_bootloader(data))
> + goto err_free_mem;
> + else
> + goto err_unregister_device;
> }
>
> - error = mxt_make_highchg(data);
> - if (error)
> - goto err_free_irq;
> + if (!mxt_in_bootloader(data)) {
> + error = mxt_make_highchg(data);
> + if (error)
> + goto err_free_irq;
> + }
>
> error = sysfs_create_group(&client->dev.kobj, &mxt_attr_group);
> if (error)
> @@ -1239,7 +1261,8 @@ static int mxt_remove(struct i2c_client *client)
>
> sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
> free_irq(data->irq, data);
> - input_unregister_device(data->input_dev);
> + if (data->input_dev)
> + input_unregister_device(data->input_dev);
> kfree(data->object_table);
> kfree(data);
>
> @@ -1253,6 +1276,9 @@ static int mxt_suspend(struct device *dev)
> struct mxt_data *data = i2c_get_clientdata(client);
> struct input_dev *input_dev = data->input_dev;
>
> + if (mxt_in_bootloader(data))
> + return 0;
> +
Hmm, so what happens if we suspend while in bootloader and maybe even
trying to flash the device? Maybe we should refuse suspend instead?
> mutex_lock(&input_dev->mutex);
>
> if (input_dev->users)
> @@ -1269,6 +1295,9 @@ static int mxt_resume(struct device *dev)
> struct mxt_data *data = i2c_get_clientdata(client);
> struct input_dev *input_dev = data->input_dev;
>
> + if (mxt_in_bootloader(data))
> + return 0;
> +
> /* Soft reset */
> mxt_write_object(data, MXT_GEN_COMMAND_T6,
> MXT_COMMAND_RESET, 1);
> --
> 1.8.1
>
--
Dmitry
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