Re: [PATCH] input: keyboard: Add sprd-keypad driver
From: wenhua lin
Date: Thu Aug 10 2023 - 22:48:48 EST
On Tue, Aug 8, 2023 at 5:07 PM Jonathan Cameron
<Jonathan.Cameron@xxxxxxxxxx> wrote:
>
> On Tue, 8 Aug 2023 15:25:01 +0800
> Wenhua Lin <Wenhua.Lin@xxxxxxxxxx> wrote:
>
> > Add matrix keypad driver, support matrix keypad function.
> >
>
> No idea why you cc'd me on this one, but I wanted some light reading whilst
> having a coffee so here's a quick review :)
>
> Hohum. Took me a bit long than planned. Ah well, I hope you find the
> feedback useful.
We may have made a mistake, your feedback is greatly appreciated,
these suggestions help us a lot.
>
> > Signed-off-by: Wenhua Lin <Wenhua.Lin@xxxxxxxxxx>
> > ---
> > drivers/input/keyboard/Kconfig | 10 +
> > drivers/input/keyboard/Makefile | 1 +
> > drivers/input/keyboard/sprd_keypad.c | 418 +++++++++++++++++++++++++++
> > 3 files changed, 429 insertions(+)
> > create mode 100644 drivers/input/keyboard/sprd_keypad.c
> >
> > diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> > index 1d0c5f4c0f99..f35d9bf05f72 100644
> > --- a/drivers/input/keyboard/Kconfig
> > +++ b/drivers/input/keyboard/Kconfig
> > @@ -809,4 +809,14 @@ config KEYBOARD_CYPRESS_SF
> > To compile this driver as a module, choose M here: the
> > module will be called cypress-sf.
> >
> > +config KEYBOARD_SPRD
> > + tristate "Spreadtrum keyboard support"
> > + depends on ARCH_SPRD || COMPILE_TEST
> > + select INPUT_MATRIXKMAP
> > + help
> > + Keypad controller is used to interface a SoC with a matrix-keypad device,
> > + The keypad controller supports multiple row and column lines.
> > + Say Y if you want to use the SPRD keyboard.
> > + Say M if you want to use the SPRD keyboard on SoC as module.
> > +
> > endif
> > diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
> > index aecef00c5d09..b747112461b1 100644
> > --- a/drivers/input/keyboard/Makefile
> > +++ b/drivers/input/keyboard/Makefile
> > @@ -66,6 +66,7 @@ obj-$(CONFIG_KEYBOARD_STOWAWAY) += stowaway.o
> > obj-$(CONFIG_KEYBOARD_ST_KEYSCAN) += st-keyscan.o
> > obj-$(CONFIG_KEYBOARD_SUN4I_LRADC) += sun4i-lradc-keys.o
> > obj-$(CONFIG_KEYBOARD_SUNKBD) += sunkbd.o
> > +obj-$(CONFIG_KEYBOARD_SPRD) += sprd_keypad.o
> > obj-$(CONFIG_KEYBOARD_TC3589X) += tc3589x-keypad.o
> > obj-$(CONFIG_KEYBOARD_TEGRA) += tegra-kbc.o
> > obj-$(CONFIG_KEYBOARD_TM2_TOUCHKEY) += tm2-touchkey.o
> > diff --git a/drivers/input/keyboard/sprd_keypad.c b/drivers/input/keyboard/sprd_keypad.c
> > new file mode 100644
> > index 000000000000..5b88072831e8
> > --- /dev/null
> > +++ b/drivers/input/keyboard/sprd_keypad.c
> > @@ -0,0 +1,418 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2018 Spreadtrum Communications Inc.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/input/matrix_keypad.h>
> > +#include <linux/io.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/clk.h>
> > +#include <linux/of.h>
> > +#include <linux/input.h>
>
> Some sort of order of headers would be good.
> Alphabetical is a good choice, though maybe Dmitry prefers something else.
We will fix this issue in patch v2.
>
> > +
> > +#define SPRD_KPD_CTRL 0x0
> > +#define SPRD_KPD_INT_EN 0x4
> > +#define SPRD_KPD_INT_RAW_STATUS 0x8
> > +#define SPRD_KPD_INT_MASK_STATUS 0xc
> > +#define SPRD_KPD_INT_CLR 0x10
> > +#define SPRD_KPD_POLARITY 0x18
> > +#define SPRD_KPD_DEBOUNCE_CNT 0x1c
> > +#define SPRD_KPD_LONG_KEY_CNT 0x20
> > +#define SPRD_KPD_SLEEP_CNT 0x24
> > +#define SPRD_KPD_CLK_DIV_CNT 0x28
> > +#define SPRD_KPD_KEY_STATUS 0x2c
> > +#define SPRD_KPD_SLEEP_STATUS 0x30
> > +#define SPRD_KPD_DEBUG_STATUS1 0x34
> > +#define SPRD_KPD_DEBUG_STATUS2 0x38
> > +
> > +#define SPRD_KPD_EN BIT(0)
> > +#define SPRD_KPD_SLEEP_EN BIT(1)
> > +#define SPRD_KPD_LONG_KEY_EN BIT(2)
> > +
> > +#define SPRD_KPD_ROWS_MSK GENMASK(23, 16)
> > +#define SPRD_KPD_COLS_MSK GENMASK(15, 8)
> > +
> > +#define SPRD_KPD_INT_ALL GENMASK(11, 0)
> > +#define SPRD_KPD_INT_DOWNUP GENMASK(7, 0)
> > +#define SPRD_KPD_INT_LONG GENMASK(11, 8)
> > +
> > +#define SPRD_KPD_ROW_POLARITY GENMASK(7, 0)
> > +#define SPRD_KPD_COL_POLARITY GENMASK(15, 8)
> > +
> > +#define SPRD_KPD_PRESS_INTX(X, V) \
> > + (((V) >> (X)) & GENMASK(0, 0))
>
> Given how this is used as a boolean check, I think
> if (SPRD_KPD_PRESS_INTX(i, int_status))
> is same as
>
> if (int_status & BIT(i)) which id easier to read.
Thanks for your suggestion, I will seriously consider it.
>
> > +#define SPRD_KPD_RELEASE_INTX(X, V) \
> > + (((V) >> ((X) + 4)) & GENMASK(0, 0))
> For this one I'd define a mask and use field get so the check
>
> if (SPRD_KPD_RELEASE_INTX(i, int_status)) {
>
> becomes
>
> #define SPRD_KPD_RELEASE_INTX_MSK GENMASK(7, 4)
>
> if (FIELD_GET(SPRD_KPD_RELEASE_INTX_MSK, int_status) & BIT(i));
>
Thanks for your suggestion, I will seriously consider it.
>
> > +#define SPRD_KPD_INTX_COL(X, V) \
> > + (((V) >> ((X) << 3)) & GENMASK(2, 0))
> > +#define SPRD_KPD_INTX_ROW(X, V) \
> > + (((V) >> (((X) << 3) + 4)) & GENMASK(2, 0))
>
> Ok, on this I'm struggling to work out what is actually happening.
>
> Looks to be picking out an 8 bit field then masking with 3 bits.
> X = 0..3
>
> So define the mask with a suitable name and provide a macro to extract
> only the 8 bit field. I would suggest using multiply as simpler.
>
> Something along the lines of...
>
> #define SPRD_KBD_INTX_COL_MSK GENMASK(2, 0)
> #define SPRD_KBD_INTX_ROW_MSK GENMASK(6, 4)
> static u8 sprd_kbd_intx_extract_entry(u32 key_input, int x)
> {
> return key_input >> (x * 8);
> }
> (key_input >> (X * 8)) & GENMASK(2, 0)
Thanks for your suggestion, but
I am concerned that the modification of the algorithm
will affect the understanding of register usage.
>
> So
> col = SPRD_KPD_INTX_COL(i, key_status);
> row = SPRD_KPD_INTX_ROW(i, key_status);
> becomes
>
> u8 entry = sprd_kbd_intx_extract_entry(key_input, i);
> col = FIELD_GET(SPRD_KBD_INTX_COL_MSK, entry)
> row = FIELD_GET(SPRD_KBD_INTX_ROW_MSK, entry);
>
> which is easier to follow than above macros.
> That of course assumes I correctly figured out what those macros
> were doing.
>
> This is a case where readability is better than short code.
>
Thanks for your suggestion, I will seriously consider it.
>
>
> > +#define SPRD_KPD_INTX_DOWN(X, V) \
> > + (((V) >> (((X) << 3) + 7)) & GENMASK(0, 0))
> > +
>
>
> > +
> > +static u32 sprd_keypad_time_to_counter(u32 array_size, u32 time_ms)
> > +{
> > + u32 value;
> > +
> > + /*
> > + * y(ms) = (x + 1) * array_size
> > + * / (32.768 / (clk_div_num + 1))
> > + * y means time in ms
> > + * x means counter
> > + * array_size equal to rows * columns
> > + * clk_div_num is devider to keypad source clock
>
> divider
> Also good to say the maths here is inverting the equation given.
We will fix this issue in patch v2.
>
> > + **/
> > + value = SPRD_KPD_RTC_HZ * time_ms;
> > + value = value / (1000 * array_size *
> > + (SPRD_DEF_DIV_CNT + 1));
> > + if (value >= 1)
> > + value -= 1;
> Good to have a comment on why this last check. Can it end up as
> less than one.
This code is implemented according to the calculation formula, and x
represents value.
y(ms) = (x + 1) * array_size / (32.768 / (clk_div_num + 1))
> > +
> > + return value;
> > +}
> > +
> > +static int sprd_keypad_hw_init(struct sprd_keypad_data *data)
> > +{
> > + u32 value;
> > +
> > + writel_relaxed(SPRD_KPD_INT_ALL, data->base + SPRD_KPD_INT_CLR);
> > + writel_relaxed(SPRD_KPD_ROW_POLARITY | SPRD_KPD_COL_POLARITY,
> > + data->base + SPRD_KPD_POLARITY);
> > + writel_relaxed(SPRD_DEF_DIV_CNT, data->base + SPRD_KPD_CLK_DIV_CNT);
> > +
> > + value = sprd_keypad_time_to_counter(data->num_rows * data->num_cols,
> > + SPRD_DEF_LONG_KEY_MS);
> > + writel_relaxed(value, data->base + SPRD_KPD_LONG_KEY_CNT);
> > +
> > + value = sprd_keypad_time_to_counter(data->num_rows * data->num_cols,
> > + data->debounce_ms);
> > + writel_relaxed(value, data->base + SPRD_KPD_DEBOUNCE_CNT);
> > +
> > + value = SPRD_KPD_INT_DOWNUP;
> > + if (data->capabilities & SPRD_CAP_LONG_KEY)
> > + value |= SPRD_KPD_INT_LONG;
> > + writel_relaxed(value, data->base + SPRD_KPD_INT_EN);
> > +
> > + value = SPRD_KPD_RTC_HZ - 1;
> > + writel_relaxed(value, data->base + SPRD_KPD_SLEEP_CNT);
> > +
> > + /* set enabled rows and columns */
> > + value = (((data->rows_en << SPRD_KPD_ROWS_SHIFT)
> > + | (data->cols_en << SPRD_KPD_COLS_SHIFT))
> > + & (SPRD_KPD_ROWS_MSK | SPRD_KPD_COLS_MSK))
> > + | SPRD_KPD_EN | SPRD_KPD_SLEEP_EN;
> > + if (data->capabilities & SPRD_CAP_LONG_KEY)
> > + value |= SPRD_KPD_LONG_KEY_EN;
> > + writel_relaxed(value, data->base + SPRD_KPD_CTRL);
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused sprd_keypad_suspend(struct device *dev)
>
> What Arnd said on this.
He made no comment on this issue.
>
> > +{
> > + struct sprd_keypad_data *data = dev_get_drvdata(dev);
> > +
> > + if (!device_may_wakeup(dev))
> > + sprd_keypad_disable(data);
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused sprd_keypad_resume(struct device *dev)
> > +{
> > + struct sprd_keypad_data *data = dev_get_drvdata(dev);
> > + int ret = 0;
> > +
> > + if (!device_may_wakeup(dev)) {
> > + ret = sprd_keypad_enable(data);
> > + if (ret)
> > + return ret;
> > + ret = sprd_keypad_hw_init(data);
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(sprd_keypad_pm_ops,
> > + sprd_keypad_suspend, sprd_keypad_resume);
> > +
> > +static int sprd_keypad_parse_dt(struct device *dev)
> > +{
> > + struct sprd_keypad_data *data = dev_get_drvdata(dev);
> > + struct device_node *np = dev->of_node;
> > + int ret;
> > +
> > + ret = matrix_keypad_parse_properties(dev, &data->num_rows, &data->num_cols);
> > + if (ret)
> > + return ret;
> > +
> > + if (data->num_rows > SPRD_KPD_ROWS_MAX
> > + || data->num_cols > SPRD_KPD_COLS_MAX) {
> > + dev_err(dev, "invalid num_rows or num_cols\n");
>
> This is only called from probe, so dev_err_probe() is appropriate throughout this
> function.
We will fix this issue in patch v2.
>
> > + return -EINVAL;
> > + }
> > +
> > + ret = of_property_read_u32(np, "debounce-interval", &data->debounce_ms);
>
> Whilst it's probably unlikely another firmware will be used with this,
> we have generic property accessors in linux/property.h that will work should anyone
> ever do so and at no cost for this driver.
We will fix this issue in patch v2.
>
> > + if (ret) {
> > + data->debounce_ms = 5;
> > + dev_warn(dev, "parse debounce-interval failed.\n");
> > + }
> > +
> > + if (of_get_property(np, "linux,repeat", NULL))
>
> device_property_read_bool() calls the check on the property being present
> so is both more general and more obvious than what you have here.
We will fix this issue in patch v2.
>
>
> > + data->capabilities |= SPRD_CAP_REPEAT;
> > + if (of_get_property(np, "sprd,support_long_key", NULL))
> > + data->capabilities |= SPRD_CAP_LONG_KEY;
> > + if (of_get_property(np, "wakeup-source", NULL))
> > + data->capabilities |= SPRD_CAP_WAKEUP;
> > +
> > + data->enable = devm_clk_get(dev, "enable");
>
> devm_clk_get_enabled() for both of these.
We will fix this issue in patch v2.
>
> > + if (IS_ERR(data->enable)) {
> > + if (PTR_ERR(data->enable) != -EPROBE_DEFER)
> > + dev_err(dev, "get enable clk failed.\n");
> > + return PTR_ERR(data->enable);
> > + }
> > +
> > + data->rtc = devm_clk_get(dev, "rtc");
> > + if (IS_ERR(data->rtc)) {
> > + if (PTR_ERR(data->enable) != -EPROBE_DEFER)
> > + dev_err(dev, "get rtc clk failed.\n");
> > + return PTR_ERR(data->rtc);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int sprd_keypad_probe(struct platform_device *pdev)
> > +{
> > + struct sprd_keypad_data *data;
> > + struct resource *res;
> > + int ret, irq, i, j, row_shift;
> > + unsigned long rows, cols;
> > + unsigned short *keycodes;
> > +
> > + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> > + if (!data)
> > + return -ENOMEM;
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + data->base = devm_ioremap_resource(&pdev->dev, res);
>
> devm_platform_get_and_ioremap_resource)
>
> > + if (IS_ERR(data->base)) {
> > + dev_err(&pdev->dev, "ioremap resource failed.\n");
> > + ret = PTR_ERR(data->base);
> > + goto err_free;
>
> Read up on what devm calls do - there is no need to manually free
> things that were allocated with them in the error paths or remove.
> So this should be a direct return. Also use
> return dev_err_probe(&pdev->dev, PTR_ERR(data->base),
> "....")
>
> It both creates neater code and for cases where deferred probing
> is possible you will get a nice message on 'why' registered for
> debug purposes.
We will fix this issue in patch v2.
>
>
> > + }
> > +
> > + platform_set_drvdata(pdev, data);
> > + ret = sprd_keypad_parse_dt(&pdev->dev);
> > + if (ret) {
> > + dev_err(&pdev->dev, "keypad parse dts failed.\n");
> > + goto err_free;
>
> Direct return and dev_err_probe()
We will fix this issue in patch v2.
>
> > + }
> > +
> > + data->input_dev = devm_input_allocate_device(&pdev->dev);
> > + if (IS_ERR(data->input_dev)) {
> > + dev_err(&pdev->dev, "alloc input dev failed.\n");
> > + ret = PTR_ERR(data->input_dev);
> > + goto err_free;
>
> Direct return, dev_err_probe() and what happened with the spacing?
We will fix this issue in patch v2.
>
> > + }
> > +
> > + data->input_dev->name = "sprd-keypad";
> > + data->input_dev->phys = "sprd-key/input0";
> > +
> > + ret = matrix_keypad_build_keymap(NULL, NULL, data->num_rows,
> > + data->num_cols, NULL, data->input_dev);
> > + if (ret) {
> > + dev_err(&pdev->dev, "keypad build keymap failed.\n");
> > + goto err_free;
>
> As above.
We will fix this issue in patch v2.
>
> > + }
> > +
> > + rows = cols = 0;
> > + row_shift = get_count_order(data->num_cols);
> > + keycodes = data->input_dev->keycode;
> > + for (i = 0; i < data->num_rows; i++) {
> > + for (j = 0; j < data->num_cols; j++) {
> > + if (!!keycodes[MATRIX_SCAN_CODE(i, j, row_shift)]) {
>
> The !! is pointless if using it as a boolean. No need to first convert it
> to 0/1 0 is false anything else is true.
>
> > + set_bit(i, &rows);
> > + set_bit(j, &cols);
> > + }
> > + }
> > + }
> > + data->rows_en = rows;
> > + data->cols_en = cols;
> > +
> > + if (data->capabilities & SPRD_CAP_REPEAT)
> > + set_bit(EV_REP, data->input_dev->evbit);
> > +
> > + input_set_drvdata(data->input_dev, data);
> > +
> > + ret = sprd_keypad_enable(data);
> > + if (ret) {
> > + dev_err(&pdev->dev, "keypad enable failed.\n");
> > + goto err_free;
> Same again.
>
> > + }
>
> I'd suggest a suitable callback and devm_add_action_or_reset()
> to unwind the enable.
>
> Actually seeing the code above, just call
> devm_clk_get_enabled() here and drop the enable / disable functions.
We will fix this issue in patch v2.
>
>
> > +
> > + ret = sprd_keypad_hw_init(data);
> > + if (ret) {
> > + dev_err(&pdev->dev, "keypad hw init failed.\n");
> > + goto clk_free;
> > + }
> > +
> > + irq = platform_get_irq(pdev, 0);
> > + if (irq < 0) {
> > + dev_err(&pdev->dev, "platform get irq failed.\n");
> > + goto clk_free;
> > + }
> > +
> > + ret = devm_request_irq(&pdev->dev, irq, sprd_keypad_handler,
> > + IRQF_NO_SUSPEND, dev_name(&pdev->dev), pdev);
> > + if (ret) {
> > + dev_err(&pdev->dev, "request irq failed.\n");
> > + goto clk_free;
> > + }
> > +
> > + ret = input_register_device(data->input_dev);
>
> Whilst there isn't a specific devm_ version of this, that is because there
> doesn't need to be one. Have a look at the implementation and how
> it handles things when input_dev->devres_managed is set.
>
> Upshot, you don't need to manually unwind this either.
I don't quite understand what you mean.
>
> > + if (ret) {
> > + dev_err(&pdev->dev, "register input dev failed\n");
> > + goto clk_free;
> > + }
> > +
> > + if (data->capabilities & SPRD_CAP_WAKEUP)
> > + device_init_wakeup(&pdev->dev, true);
> Another devm_add_action_or_reset() use case. Note: only register
> the cleanup, if you use device_init_wakeup() here.
Thanks for your suggestion, I will seriously consider it.
>
> > +
> > + return 0;
> > +
> > +clk_free:
> > + sprd_keypad_disable(data);
> > +err_free:
> > + devm_kfree(&pdev->dev, data);
> With changes above, there will be no manual cleanup to do here.
We will fix this issue in patch v2.
> > + return ret;
> > +}
> > +
> > +static int sprd_keypad_remove(struct platform_device *pdev)
> > +{
> > + struct sprd_keypad_data *data = platform_get_drvdata(pdev);
> > + int irq = platform_get_irq(pdev, 0);
> > +
> > + if (data->capabilities & SPRD_CAP_WAKEUP)
> > + device_init_wakeup(&pdev->dev, false);
> > +
> > + input_unregister_device(data->input_dev);
> > + devm_free_irq(&pdev->dev, irq, pdev);
>
> Calling a devm free is usually a bad sign and implies you shouldn't have used
> devm to get the thing in the first place.
> The two should not be mixed - so the moment you reach a call in probe() that
> you don't want to use devm_ managed releases for, stop using them for everything
> after that point. There is devm_add_action_or_reset() though which can be used
> to register your own cleanup functions and sometimes lets you take the whole
> of the release flow device managed.
>
> Suggestions above mean you will have no remove() function at all.
Thanks for your suggestion, I will seriously consider it.
>
>
> > + sprd_keypad_disable(data);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id sprd_keypad_match[] = {
> > + { .compatible = "sprd,sc9860-keypad", },
> > + {},
> > +};
> > +
> > +static struct platform_driver sprd_keypad_driver = {
> > + .driver = {
> > + .name = "sprd-keypad",
> > + .owner = THIS_MODULE,
> > + .of_match_table = sprd_keypad_match,
> > + .pm = &sprd_keypad_pm_ops,
> > + },
> > + .probe = sprd_keypad_probe,
> > + .remove = sprd_keypad_remove,
> > +};
> > +
> > +module_platform_driver(sprd_keypad_driver);
> > +
> > +MODULE_DESCRIPTION("Spreadtrum KPD Driver");
> > +MODULE_LICENSE("GPL");
> > +MODULE_AUTHOR("Neo Hou <neo.hou@xxxxxxxxxx>");
>