Subject: [PATCH] arm: sunxi: input: RFC: Add sysfs voltage for sun4i-lradc driver

From: [email-masked] (Dmitry Torokhov)
Date: Mon, 26 Jan 2015 14:06:22 -0800

On Mon, Jan 26, 2015 at 08:28:29PM +0100, Hans de Goede wrote:
> Hi,
> 
> On 26-01-15 17:58, Priit Laes wrote:
> 
> No commit message? Please write an informative commit msg, like why we want this patch,
> I guess it is to help figuring out the voltage levels for various buttons when creating
> a dts, but I would prefer to not guess, which is where a good commit message would
> come in handy ...
> 
> >---
> >  .../ABI/testing/sysfs-driver-input-sun4i-lradc     |  4 ++
> >  drivers/input/keyboard/sun4i-lradc-keys.c          | 49 +++++++++++++++++-----
> >  2 files changed, 43 insertions(+), 10 deletions(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc
> >
> >diff --git a/Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc b/Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc
> >new file mode 100644
> >index 0000000..e4e6448
> >--- /dev/null
> >+++ b/Documentation/ABI/testing/sysfs-driver-input-sun4i-lradc
> >@@ -0,0 +1,4 @@
> >+What:		/sys/class/input/input(x)/device/voltage
> >+Date:		February 2015
> >+Contact:	Priit Laes <[email-masked]>
> >+Description:	ADC output voltage in microvolts or 0 if device is not opened.
> >diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
> >index cc8f7dd..c0ab8ec 100644
> >--- a/drivers/input/keyboard/sun4i-lradc-keys.c
> >+++ b/drivers/input/keyboard/sun4i-lradc-keys.c
> >@@ -79,10 +79,27 @@ struct sun4i_lradc_data {
> >  	u32 vref;
> >  };
> >
> >+static u32 sun4i_lradc_read_voltage(struct sun4i_lradc_data *lradc)
> >+{
> >+	u32 val = readl(lradc->base + LRADC_DATA0) & 0x3f;
> >+	return val * lradc->vref / 63;
> >+};
> >+
> >+static ssize_t
> >+sun4i_lradc_dev_voltage_show(struct device *dev,
> >+			struct device_attribute *attr, char *buf)
> >+{
> >+	struct sun4i_lradc_data *lradc = dev_get_drvdata(dev);
> >+
> >+	return sprintf(buf, "%u\n", sun4i_lradc_read_voltage(lradc));
> >+}
> >+
> >+static const DEVICE_ATTR(voltage, S_IRUGO, sun4i_lradc_dev_voltage_show, NULL);
> >+
> >  static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
> >  {
> >  	struct sun4i_lradc_data *lradc = dev_id;
> >-	u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
> >+	u32 i, ints, voltage, diff, keycode = 0, closest = 0xffffffff;
> >
> >  	ints  = readl(lradc->base + LRADC_INTS);
> >
> >@@ -97,8 +114,7 @@ static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
> >  	}
> >
> >  	if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
> >-		val = readl(lradc->base + LRADC_DATA0) & 0x3f;
> >-		voltage = val * lradc->vref / 63;
> >+		voltage = sun4i_lradc_read_voltage(lradc);
> >
> >  		for (i = 0; i < lradc->chan0_map_count; i++) {
> >  			diff = abs(lradc->chan0_map[i].voltage - voltage);
> >@@ -156,7 +172,7 @@ static void sun4i_lradc_close(struct input_dev *dev)
> >  }
> >
> >  static int sun4i_lradc_load_dt_keymap(struct device *dev,
> >-				      struct sun4i_lradc_data *lradc)
> >+				    struct sun4i_lradc_data *lradc)
> >  {
> >  	struct device_node *np, *pp;
> >  	int i;
> 
> Why this identation change ?
> 
> >@@ -168,8 +184,8 @@ static int sun4i_lradc_load_dt_keymap(struct device *dev,
> >
> >  	lradc->chan0_map_count = of_get_child_count(np);
> >  	if (lradc->chan0_map_count == 0) {
> >-		dev_err(dev, "keymap is missing in device tree\n");
> >-		return -EINVAL;
> >+		dev_info(dev, "keymap is missing in device tree\n");
> >+		return 0;
> >  	}
> >
> >  	lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
> 
> I assume this is so that people can still use the sysfs node, to create a dts, right
> not sure I like this, might be better to document to simple create a dts with
> a single button mapping for 200 mV (most board use 200 mV steps between the buttons).
> 
> >@@ -185,19 +201,19 @@ static int sun4i_lradc_load_dt_keymap(struct device *dev,
> >
> >  		error = of_property_read_u32(pp, "channel", &channel);
> >  		if (error || channel != 0) {
> >-			dev_err(dev, "%s: Inval channel prop\n", pp->name);
> >+			dev_err(dev, "%s: Invalid 'channel' property\n", pp->name);
> >  			return -EINVAL;
> >  		}
> >
> >  		error = of_property_read_u32(pp, "voltage", &map->voltage);
> >  		if (error) {
> >-			dev_err(dev, "%s: Inval voltage prop\n", pp->name);
> >+			dev_err(dev, "%s: Invalid 'voltage' property\n", pp->name);
> >  			return -EINVAL;
> >  		}
> >
> >  		error = of_property_read_u32(pp, "linux,code", &map->keycode);
> >  		if (error) {
> >-			dev_err(dev, "%s: Inval linux,code prop\n", pp->name);
> >+			dev_err(dev, "%s: Invalid 'linux,code' property\n", pp->name);
> >  			return -EINVAL;
> >  		}
> >
> 
> This hunk / 3 changes belong in a separate patch. Also please run checkpatch, I think
> you're running over 80 chars here.
> 
> 
> >@@ -257,14 +273,26 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
> >  	if (error)
> >  		return error;
> >
> >-	error = input_register_device(lradc->input);
> >+	error = device_create_file(dev, &dev_attr_voltage);
> >  	if (error)
> >  		return error;
> >
> >+	error = input_register_device(lradc->input);
> >+	if (error) {
> >+		device_remove_file(&pdev->dev, &dev_attr_voltage);
> >+		return error;
> >+	}
> >+
> >  	platform_set_drvdata(pdev, lradc);
> >  	return 0;
> >  }
> >
> >+static int sun4i_lradc_remove(struct platform_device *pdev)
> >+{
> >+	device_remove_file(&pdev->dev, &dev_attr_voltage);
> >+	return 0;
> >+}
> >+
> 
> This looks wrong, I think (*) that we've a bug here because we're not
> unregistering the input device, so maybe do 2 patches, 1 fixing the
> not unregistering bug, and then just add the device_remove_file()
> in the sysfs patch.

The unregister was not necessary since the input device is managed.

-- 
Dmitry