[PATCH] arm: sunxi: input: RFC: Add sysfs voltage for sun4i-lradc driver
Dmitry Torokhov
dmitry.torokhov at gmail.com
Tue Jan 27 11:31:26 PST 2015
On Tue, Jan 27, 2015 at 10:03:35AM +0100, Hans de Goede wrote:
> Hi,
>
> On 26-01-15 23:06, Dmitry Torokhov wrote:
> >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 <plaes at plaes.org>
> >>>+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.
>
> Ah right, looking at the code again I see we use devm_input_allocate_device()
> is there no devm_create_file for creating sysfs entries ?
Greg was pushing the viewpoint that no drivers should create device attributes
manually (since it is somewhat racy - attributes are created after devices show
up) but I do not think he's gonna win that ever. So if someone were to add
devm_create_attribute_group() API I think that would be great. In absence of
this there is always devm_add_action().
Thanks.
--
Dmitry
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