Re: [PATCH v21 2/3] Input: mt6779-keypad - Add MediaTek keypad driver

AngeloGioacchino Del Regno
2022-03-04T10:31:47Z

Il 03/03/22 16:43, Mattijs Korpershoek ha scritto:
> From: "fengping.yu" <fengping.yu@mediatek.com>
>
> This patch adds matrix keypad support for Mediatek SoCs.
>
> Signed-off-by: fengping.yu <fengping.yu@mediatek.com>
> Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
> Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

Hello Mattijs,
thanks for the patch!

However, to make it perfect, there's something to improve....

> ---
> drivers/input/keyboard/Kconfig | 12 ++
> drivers/input/keyboard/Makefile | 1 +
> drivers/input/keyboard/mt6779-keypad.c | 215 +++++++++++++++++++++++++
> 3 files changed, 228 insertions(+)
> create mode 100644 drivers/input/keyboard/mt6779-keypad.c
>
> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> index 0c607da9ee10..03a9530f620e 100644
> --- a/drivers/input/keyboard/Kconfig
> +++ b/drivers/input/keyboard/Kconfig
> @@ -779,6 +779,18 @@ config KEYBOARD_BCM
> To compile this driver as a module, choose M here: the
> module will be called bcm-keypad.
>
> +config KEYBOARD_MT6779
> + tristate "MediaTek Keypad Support"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + select REGMAP_MMIO
> + select INPUT_MATRIXKMAP
> + help
> + Say Y here if you want to use the keypad on MediaTek SoCs.
> + If unsure, say N.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called mt6779-keypad.
> +
> config KEYBOARD_MTK_PMIC
> tristate "MediaTek PMIC keys support"
> depends on MFD_MT6397
> diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
> index e3c8648f834e..721936e90290 100644
> --- a/drivers/input/keyboard/Makefile
> +++ b/drivers/input/keyboard/Makefile
> @@ -44,6 +44,7 @@ obj-$(CONFIG_KEYBOARD_MATRIX) += matrix_keypad.o
> obj-$(CONFIG_KEYBOARD_MAX7359) += max7359_keypad.o
> obj-$(CONFIG_KEYBOARD_MCS) += mcs_touchkey.o
> obj-$(CONFIG_KEYBOARD_MPR121) += mpr121_touchkey.o
> +obj-$(CONFIG_KEYBOARD_MT6779) += mt6779-keypad.o
> obj-$(CONFIG_KEYBOARD_MTK_PMIC) += mtk-pmic-keys.o
> obj-$(CONFIG_KEYBOARD_NEWTON) += newtonkbd.o
> obj-$(CONFIG_KEYBOARD_NOMADIK) += nomadik-ske-keypad.o
> diff --git a/drivers/input/keyboard/mt6779-keypad.c b/drivers/input/keyboard/mt6779-keypad.c
> new file mode 100644
> index 000000000000..b207acdd1e2a
> --- /dev/null
> +++ b/drivers/input/keyboard/mt6779-keypad.c
> @@ -0,0 +1,215 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2022 MediaTek Inc.
> + * Author Fengping Yu <fengping.yu@mediatek.com>
> + */
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/input/matrix_keypad.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define MTK_KPD_NAME "mt6779-keypad"
> +#define MTK_KPD_MEM 0x0004
> +#define MTK_KPD_DEBOUNCE 0x0018
> +#define MTK_KPD_DEBOUNCE_MASK GENMASK(13, 0)
> +#define MTK_KPD_DEBOUNCE_MAX_MS 256
> +#define MTK_KPD_NUM_MEMS 5
> +#define MTK_KPD_NUM_BITS 136 /* 4*32+8 MEM5 only use 8 BITS */
> +
> +struct mt6779_keypad {
> + struct regmap *regmap;
> + struct input_dev *input_dev;
> + struct clk *clk;
> + void __iomem *base;
> + u32 n_rows;
> + u32 n_cols;
> + DECLARE_BITMAP(keymap_state, MTK_KPD_NUM_BITS);
> +};
> +
> +static const struct regmap_config mt6779_keypad_regmap_cfg = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = sizeof(u32),
> + .max_register = 36,

Are you sure that you can't use .fast_io = true?

Another version for the same question:
Are you sure that you need to lock with a mutex here, and not with a spinlock?

Since you're performing reads over a MMIO, I think that there's a very good
chance that you can use fast_io.

> +};
> +
> +static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)
> +{
> + struct mt6779_keypad *keypad = dev_id;
> + unsigned short *keycode = keypad->input_dev->keycode;
> + DECLARE_BITMAP(new_state, MTK_KPD_NUM_BITS);
> + DECLARE_BITMAP(change, MTK_KPD_NUM_BITS);
> + int bit_nr;
> + int pressed;
> + unsigned short code;
> + int row, col;
> + int row_shift = get_count_order(keypad->n_cols);
> +
> + regmap_bulk_read(keypad->regmap, MTK_KPD_MEM,
> + new_state, MTK_KPD_NUM_MEMS);
> +
> + bitmap_xor(change, new_state, keypad->keymap_state, MTK_KPD_NUM_BITS);
> +
> + for_each_set_bit(bit_nr, change, MTK_KPD_NUM_BITS) {
> + /* For 32bits register, only bits [15:0] use to indicate key status */
> + if (bit_nr % 32 >= 16)
> + continue;
> +
> + /* 1: not pressed, 0: pressed */
> + pressed = !test_bit(bit_nr, new_state);
> + dev_dbg(&keypad->input_dev->dev, "%s",
> + pressed ? "pressed" : "released");
> +
> + row = bit_nr / 32;
> + col = bit_nr % 32;
> +
> + code = keycode[MATRIX_SCAN_CODE(row, col, row_shift)];
> +
> + input_report_key(keypad->input_dev, code, pressed);
> + input_sync(keypad->input_dev);
> +
> + dev_dbg(&keypad->input_dev->dev,
> + "report Linux keycode = %d\n", code);
> + }
> +
> + bitmap_copy(keypad->keymap_state, new_state, MTK_KPD_NUM_BITS);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void mt6779_keypad_clk_disable(void *data)
> +{
> + clk_disable_unprepare(data);
> +}
> +
> +static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
> +{
> + struct mt6779_keypad *keypad;
> + unsigned int irq;
> + u32 debounce;
> + bool wakeup;
> + int error;
> +
> + keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
> + if (!keypad)
> + return -ENOMEM;
> +
> + keypad->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(keypad->base))
> + return PTR_ERR(keypad->base);
> +
> + keypad->regmap = devm_regmap_init_mmio(&pdev->dev,
> + keypad->base,
> + &mt6779_keypad_regmap_cfg);

Please use dev_err_probe() to simplify error handling in probe functions: you've
done a great job with adding a devm action for the error cases, avoiding gotos to
get out cleanly.. it would be a pity to not finish this to perfection.

I'll give you two examples for this, so that you'll be all set.

if (IS_ERR(keypad->regmap))
return dev_err_probe(&pdev->dev, PTR_ERR(keypad->regmap),
"regmap init failed\n");

P.S.: No need for %pe here, as dev_err_probe prints the error number for you!

> + if (IS_ERR(keypad->regmap)) {
> + dev_err(&pdev->dev,
> + "regmap init failed:%pe\n", keypad->regmap);
> + return PTR_ERR(keypad->regmap);
> + }
> +
> + bitmap_fill(keypad->keymap_state, MTK_KPD_NUM_BITS);
> +
> + keypad->input_dev = devm_input_allocate_device(&pdev->dev);

if (!keypad->input_dev)
return dev_err_probe(&pdev->dev, -ENOMEM,
"Cannot allocate input device\n");

> + if (!keypad->input_dev) {
> + dev_err(&pdev->dev, "Failed to allocate input dev\n");
> + return -ENOMEM;
> + }
> +
> + keypad->input_dev->name = MTK_KPD_NAME;
> + keypad->input_dev->id.bustype = BUS_HOST;
> +
> + error = matrix_keypad_parse_properties(&pdev->dev, &keypad->n_rows,
> + &keypad->n_cols);
> + if (error) {
> + dev_err(&pdev->dev, "Failed to parse keypad params\n");
> + return error;
> + }
> +
> + if (device_property_read_u32(&pdev->dev, "debounce-delay-ms",
> + &debounce))
> + debounce = 16;
> +
> + if (debounce > MTK_KPD_DEBOUNCE_MAX_MS) {
> + dev_err(&pdev->dev, "Debounce time exceeds the maximum allowed time %dms\n",
> + MTK_KPD_DEBOUNCE_MAX_MS);
> + return -EINVAL;
> + }
> +
> + wakeup = device_property_read_bool(&pdev->dev, "wakeup-source");
> +
> + dev_dbg(&pdev->dev, "n_row=%d n_col=%d debounce=%d\n",
> + keypad->n_rows, keypad->n_cols, debounce);
> +
> + error = matrix_keypad_build_keymap(NULL, NULL,
> + keypad->n_rows,
> + keypad->n_cols,
> + NULL,
> + keypad->input_dev);
> + if (error) {
> + dev_err(&pdev->dev, "Failed to build keymap\n");
> + return error;
> + }
> +
> + regmap_write(keypad->regmap, MTK_KPD_DEBOUNCE,
> + (debounce * (1 << 5)) & MTK_KPD_DEBOUNCE_MASK);
> +
> + keypad->clk = devm_clk_get(&pdev->dev, "kpd");
> + if (IS_ERR(keypad->clk))
> + return PTR_ERR(keypad->clk);
> +
> + error = clk_prepare_enable(keypad->clk);
> + if (error) {
> + dev_err(&pdev->dev, "cannot prepare/enable keypad clock\n");
> + return error;
> + }
> +
> + error = devm_add_action_or_reset(&pdev->dev, mt6779_keypad_clk_disable, keypad->clk);
> + if (error)
> + return error;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> +
> + error = devm_request_threaded_irq(&pdev->dev, irq, NULL, mt6779_keypad_irq_handler,
> + IRQF_ONESHOT, MTK_KPD_NAME, keypad);
> + if (error) {
> + dev_err(&pdev->dev, "Failed to request IRQ#%d:%d\n", irq, error);
> + return error;
> + }
> +
> + error = input_register_device(keypad->input_dev);
> + if (error) {
> + dev_err(&pdev->dev, "Failed to register device\n");
> + return error;
> + }
> +
> + error = device_init_wakeup(&pdev->dev, wakeup);

Whoops! Two spaces here! Please fix this typo.

P.S.: Please add my email to the Cc's when you'll send the next version, so that
I will be able to timely give you a R-b tag.

Cheers,
Angelo