On ven., mars 04, 2022 at 11:31, AngeloGioacchino Del Regno [off-list ref] wrote:

Il 03/03/22 16:43, Mattijs Korpershoek ha scritto:

quoted

From: "fengping.yu" <redacted>

This patch adds matrix keypad support for Mediatek SoCs.

Signed-off-by: fengping.yu <redacted>
Reviewed-by: Marco Felsch <redacted>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mattijs Korpershoek <redacted>
Signed-off-by: Mattijs Korpershoek <redacted>

Hello Mattijs,
thanks for the patch!

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

Hi Angelo,

Thank you for your detailed review, It's really appreciated!

quoted

---
  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?

I am not sure at all. I did not think twice about this.

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.

Thank you for this suggestion. I might send a follow-up series with this
improvement included.
Will cc you if I do.

quoted

+};
+
+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!

I did not know about dev_err_probe(). As far as I understand, it's not
recommended to be used for input drivers, but I'll definitely use it for
other subsystems.

quoted

+	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");

quoted

+	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.

It looks Dmitry fixed this already in his tree [1]

[1] https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git/commit/?h=next&id=f28af984e771efd1ded81b865b50fa13b69bcde5

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