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SubjectRe: [PATCH v17 2/3] drivers: input: keyboard: Add mtk keypad driver
On Mon, Aug 10, 2020 at 02:51:28PM +0800, Fengping Yu wrote:
> 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>
> ---
> drivers/input/keyboard/Kconfig | 11 ++
> drivers/input/keyboard/Makefile | 1 +
> drivers/input/keyboard/mtk-kpd.c | 209 +++++++++++++++++++++++++++++++
> 3 files changed, 221 insertions(+)
> create mode 100644 drivers/input/keyboard/mtk-kpd.c
>
> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> index 793ecbbda32c..1ee845c292c6 100644
> --- a/drivers/input/keyboard/Kconfig
> +++ b/drivers/input/keyboard/Kconfig
> @@ -782,6 +782,17 @@ config KEYBOARD_BCM
> To compile this driver as a module, choose M here: the
> module will be called bcm-keypad.
>
> +config KEYBOARD_MTK_KPD
> + 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 mtk-kpd.
> +
> 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 1d689fdd5c00..6c9d852c377e 100644
> --- a/drivers/input/keyboard/Makefile
> +++ b/drivers/input/keyboard/Makefile
> @@ -43,6 +43,7 @@ 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-$(CONFIG_KEYBOARD_MTK_KPD) += mtk-kpd.o
> obj-$(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/mtk-kpd.c b/drivers/input/keyboard/mtk-kpd.c
> new file mode 100644
> index 000000000000..451b3bc61c6f
> --- /dev/null
> +++ b/drivers/input/keyboard/mtk-kpd.c
> @@ -0,0 +1,209 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 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 "mtk-kpd"
> +#define MTK_KPD_MEM 0x0004
> +#define MTK_KPD_DEBOUNCE 0x0018
> +#define MTK_KPD_DEBOUNCE_MASK GENMASK(13, 0)
> +#define MTK_KPD_DEBOUNCE_MAX_US 256000
> +#define MTK_KPD_NUM_MEMS 5
> +#define MTK_KPD_NUM_BITS 136 /* 4*32+8 MEM5 only use 8 BITS */
> +
> +struct mtk_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 keypad_regmap_cfg = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = sizeof(u32),
> + .max_register = 36,
> +};
> +
> +static irqreturn_t kpd_irq_handler(int irq, void *dev_id)
> +{
> + struct mtk_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;
> +
> + 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) {

Should we be explicit:

if (bit_nr % 32 >= 16) // or "if ((bit_nr / 16) % 2)"
continue;

so that we sure we do not trip over garbage (if any) in the unused
bits?


> + /* 1: not pressed, 0: pressed */
> + pressed = !test_bit(bit_nr, new_state);
> + dev_dbg(&keypad->input_dev->dev, "%s",
> + pressed ? "pressed" : "released");
> +
> + /* 32bit register only use low 16bit as keypad mem register */
> + code = keycode[bit_nr - 16 * (BITS_TO_U32(bit_nr) - 1)];

This will give index of 16 for (0,0). Is this what we want? Hmm, this is
all weird... I think we need:

row = bit_nr / 32;
col = bit_nr % 32;
if (col > 15)
continue;

// set row_shift in probe() as:
// keypad_data->row_shift =
// get_count_order(keypad_data->n_cols);
code = keycode[MATRIX_SCAN_CODE(row, col,
keypad_data->row_shift)];

This will properly unpack the keymap built by
matrix_keypad_build_keymap().

> +
> + 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 kpd_clk_disable(void *data)
> +{
> + clk_disable_unprepare(data);
> +}
> +
> +static int kpd_pdrv_probe(struct platform_device *pdev)
> +{
> + struct mtk_keypad *keypad;
> + unsigned int irq;
> + u32 debounce;
> + bool wakeup;
> + int ret;

Can we call this variable "error" please?

> +
> + 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,
> + &keypad_regmap_cfg);
> + 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) {
> + 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;
> +
> + ret = matrix_keypad_parse_properties(&pdev->dev, &keypad->n_rows,
> + &keypad->n_cols);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to parse keypad params\n");
> + return ret;
> + }
> +
> + if (device_property_read_u32(&pdev->dev, "mediatek,debounce-us",
> + &debounce))
> + debounce = 16000;
> +
> + if (debounce > MTK_KPD_DEBOUNCE_MAX_US) {
> + dev_err(&pdev->dev, "Debounce time exceeds the maximum allowed time %dus\n",
> + MTK_KPD_DEBOUNCE_MAX_US);
> + 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);
> +
> + ret = matrix_keypad_build_keymap(NULL, NULL,
> + keypad->n_rows,
> + keypad->n_cols,
> + NULL,
> + keypad->input_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to build keymap\n");
> + return ret;
> + }
> +
> + regmap_write(keypad->regmap, MTK_KPD_DEBOUNCE,
> + debounce * 32 / 1000 & MTK_KPD_DEBOUNCE_MASK);
> +
> + keypad->clk = devm_clk_get(&pdev->dev, "kpd");
> + if (IS_ERR(keypad->clk))
> + return PTR_ERR(keypad->clk);
> +
> + ret = clk_prepare_enable(keypad->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "cannot prepare/enable keypad clock\n");
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(&pdev->dev, kpd_clk_disable, keypad->clk);
> + if (ret)
> + return ret;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> +
> + ret = devm_request_threaded_irq(&pdev->dev, irq,
> + NULL, kpd_irq_handler, IRQF_ONESHOT,
> + MTK_KPD_NAME, keypad);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to request IRQ#%d:%d\n",
> + irq, ret);
> + return ret;
> + }
> +
> + ret = input_register_device(keypad->input_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register device\n");
> + return ret;
> + }
> +
> + ret = device_init_wakeup(&pdev->dev, wakeup);
> + if (ret)
> + dev_warn(&pdev->dev, "device_init_wakeup fail\n");
> +
> + return 0;
> +}
> +
> +static const struct of_device_id kpd_of_match[] = {
> + { .compatible = "mediatek,mt6779-keypad" },
> + { .compatible = "mediatek,mt6873-keypad" },
> + { /* sentinel */ }
> +};
> +
> +static struct platform_driver kpd_pdrv = {
> + .probe = kpd_pdrv_probe,
> + .driver = {
> + .name = MTK_KPD_NAME,
> + .of_match_table = kpd_of_match,
> + },
> +};
> +module_platform_driver(kpd_pdrv);
> +
> +MODULE_AUTHOR("Mediatek Corporation");
> +MODULE_DESCRIPTION("MTK Keypad (KPD) Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.18.0

Thanks.

--
Dmitry

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