[v1,31/63] Input: atmel_mxt_ts - add memory access interface via sysfs
diff mbox series

Message ID 20190816083451.18947-2-jiada_wang@mentor.com
State Superseded
Headers show
Series
  • atmel_mxt_ts misc
Related show

Commit Message

Jiada Wang Aug. 16, 2019, 8:34 a.m. UTC
From: Nick Dyer <nick.dyer@itdev.co.uk>

Atmel maXTouch chips can be addressed via an "Object Based Protocol" which
defines how i2c registers are mapped to different functions within the
chips. This interface exposes the register map and allows user-space
utilities to inspect and alter object configuration, and to view diagnostic
data, while the device is running.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
(cherry picked from ndyer/linux/for-upstream commit 80731e95c888d09b663ad9eeaf4163939bfe17f8)
Signed-off-by: George G. Davis <george_davis@mentor.com>
[jiada: Fix compilation warnings]
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 74 ++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

Comments

dmitry.torokhov@gmail.com Aug. 16, 2019, 5:29 p.m. UTC | #1
On Fri, Aug 16, 2019 at 05:34:19PM +0900, Jiada Wang wrote:
> From: Nick Dyer <nick.dyer@itdev.co.uk>
> 
> Atmel maXTouch chips can be addressed via an "Object Based Protocol" which
> defines how i2c registers are mapped to different functions within the
> chips. This interface exposes the register map and allows user-space
> utilities to inspect and alter object configuration, and to view diagnostic
> data, while the device is running.

I'd say if we want this we should look into write support in regmap and
switching the driver over.

Thanks.
Jiada Wang Aug. 23, 2019, 3 a.m. UTC | #2
Hi Dmitry

On 2019/08/17 2:29, Dmitry Torokhov wrote:
> On Fri, Aug 16, 2019 at 05:34:19PM +0900, Jiada Wang wrote:
>> From: Nick Dyer <nick.dyer@itdev.co.uk>
>>
>> Atmel maXTouch chips can be addressed via an "Object Based Protocol" which
>> defines how i2c registers are mapped to different functions within the
>> chips. This interface exposes the register map and allows user-space
>> utilities to inspect and alter object configuration, and to view diagnostic
>> data, while the device is running.
> 
> I'd say if we want this we should look into write support in regmap and
> switching the driver over.
> 
since switch to regmap is non-trival, I will drop this patch in v2 patchset

Thanks,
Jiada
> Thanks.
>

Patch
diff mbox series

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index e317900279ed..05b21c9c0c04 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -335,6 +335,7 @@  struct mxt_data {
 	u8 t100_aux_ampl;
 	u8 t100_aux_area;
 	u8 t100_aux_vect;
+	struct bin_attribute mem_access_attr;
 	bool debug_enabled;
 	u8 max_reportid;
 	u32 config_crc;
@@ -3553,6 +3554,56 @@  static ssize_t mxt_debug_enable_store(struct device *dev,
 	return ret;
 }
 
+static int mxt_check_mem_access_params(struct mxt_data *data, loff_t off,
+				       size_t *count)
+{
+	if (off >= data->mem_size)
+		return -EIO;
+
+	if (off + *count > data->mem_size)
+		*count = data->mem_size - off;
+
+	if (*count > MXT_MAX_BLOCK_WRITE)
+		*count = MXT_MAX_BLOCK_WRITE;
+
+	return 0;
+}
+
+static ssize_t mxt_mem_access_read(struct file *filp, struct kobject *kobj,
+	struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct mxt_data *data = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = mxt_check_mem_access_params(data, off, &count);
+	if (ret < 0)
+		return ret;
+
+	if (count > 0)
+		ret = __mxt_read_reg(data->client, off, count, buf);
+
+	return ret == 0 ? (ssize_t)count : ret;
+}
+
+static ssize_t mxt_mem_access_write(struct file *filp, struct kobject *kobj,
+	struct bin_attribute *bin_attr, char *buf, loff_t off,
+	size_t count)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct mxt_data *data = dev_get_drvdata(dev);
+	int ret = 0;
+
+	ret = mxt_check_mem_access_params(data, off, &count);
+	if (ret < 0)
+		return ret;
+
+	if (count > 0)
+		ret = __mxt_write_reg(data->client, off, count, buf);
+
+	return ret == 0 ? (ssize_t)count : ret;
+}
+
 static DEVICE_ATTR(update_fw, S_IWUSR, NULL, mxt_update_fw_store);
 
 static struct attribute *mxt_fw_attrs[] = {
@@ -3598,13 +3649,36 @@  static int mxt_sysfs_init(struct mxt_data *data)
 		return error;
 	}
 
+	sysfs_bin_attr_init(&data->mem_access_attr);
+	data->mem_access_attr.attr.name = "mem_access";
+	data->mem_access_attr.attr.mode = S_IRUGO | S_IWUSR;
+	data->mem_access_attr.read = mxt_mem_access_read;
+	data->mem_access_attr.write = mxt_mem_access_write;
+	data->mem_access_attr.size = data->mem_size;
+
+	error = sysfs_create_bin_file(&client->dev.kobj,
+				  &data->mem_access_attr);
+	if (error) {
+		dev_err(&client->dev, "Failed to create %s\n",
+			data->mem_access_attr.attr.name);
+		goto err_remove_sysfs_group;
+	}
+
 	return 0;
+
+err_remove_sysfs_group:
+	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
+	return error;
 }
 
 static void mxt_sysfs_remove(struct mxt_data *data)
 {
 	struct i2c_client *client = data->client;
 
+	if (data->mem_access_attr.attr.name)
+		sysfs_remove_bin_file(&client->dev.kobj,
+				      &data->mem_access_attr);
+
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 }