// SPDX-License-Identifier: GPL-2.0-or-later /* * Allwinner sun4i low res adc attached tablet keys driver * * Copyright (C) 2014 Hans de Goede */ /* * Allwinnner sunxi SoCs have a lradc which is specifically designed to have * various (tablet) keys (ie home, back, search, etc). attached to it using * a resistor network. This driver is for the keys on such boards. * * There are 2 channels, currently this driver only supports channel 0 since * there are no boards known to use channel 1. */ #include #include #include #include #include #include #include #include #include #include #define LRADC_CTRL 0x00 #define LRADC_INTC 0x04 #define LRADC_INTS 0x08 #define LRADC_DATA0 0x0c #define LRADC_DATA1 0x10 /* LRADC_CTRL bits */ #define FIRST_CONVERT_DLY(x) ((x) << 24) /* 8 bits */ #define CHAN_SELECT(x) ((x) << 22) /* 2 bits */ #define CONTINUE_TIME_SEL(x) ((x) << 16) /* 4 bits */ #define KEY_MODE_SEL(x) ((x) << 12) /* 2 bits */ #define LEVELA_B_CNT(x) ((x) << 8) /* 4 bits */ #define HOLD_KEY_EN(x) ((x) << 7) #define HOLD_EN(x) ((x) << 6) #define LEVELB_VOL(x) ((x) << 4) /* 2 bits */ #define SAMPLE_RATE(x) ((x) << 2) /* 2 bits */ #define ENABLE(x) ((x) << 0) /* LRADC_INTC and LRADC_INTS bits */ #define CHAN1_KEYUP_IRQ BIT(12) #define CHAN1_ALRDY_HOLD_IRQ BIT(11) #define CHAN1_HOLD_IRQ BIT(10) #define CHAN1_KEYDOWN_IRQ BIT(9) #define CHAN1_DATA_IRQ BIT(8) #define CHAN0_KEYUP_IRQ BIT(4) #define CHAN0_ALRDY_HOLD_IRQ BIT(3) #define CHAN0_HOLD_IRQ BIT(2) #define CHAN0_KEYDOWN_IRQ BIT(1) #define CHAN0_DATA_IRQ BIT(0) /* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant * @divisor_numerator: The numerator of lradc Vref internally divisor * @divisor_denominator: The denominator of lradc Vref internally divisor */ struct lradc_variant { u8 divisor_numerator; u8 divisor_denominator; }; static const struct lradc_variant lradc_variant_a10 = { .divisor_numerator = 2, .divisor_denominator = 3 }; static const struct lradc_variant r_lradc_variant_a83t = { .divisor_numerator = 3, .divisor_denominator = 4 }; struct sun4i_lradc_keymap { u32 voltage; u32 keycode; }; struct sun4i_lradc_data { struct device *dev; struct input_dev *input; void __iomem *base; struct regulator *vref_supply; struct sun4i_lradc_keymap *chan0_map; const struct lradc_variant *variant; u32 chan0_map_count; u32 chan0_keycode; u32 vref; }; 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; ints = readl(lradc->base + LRADC_INTS); /* * lradc supports only one keypress at a time, release does not give * any info as to which key was released, so we cache the keycode. */ if (ints & CHAN0_KEYUP_IRQ) { input_report_key(lradc->input, lradc->chan0_keycode, 0); lradc->chan0_keycode = 0; } if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) { val = readl(lradc->base + LRADC_DATA0) & 0x3f; voltage = val * lradc->vref / 63; for (i = 0; i < lradc->chan0_map_count; i++) { diff = abs(lradc->chan0_map[i].voltage - voltage); if (diff < closest) { closest = diff; keycode = lradc->chan0_map[i].keycode; } } lradc->chan0_keycode = keycode; input_report_key(lradc->input, lradc->chan0_keycode, 1); } input_sync(lradc->input); writel(ints, lradc->base + LRADC_INTS); return IRQ_HANDLED; } static int sun4i_lradc_open(struct input_dev *dev) { struct sun4i_lradc_data *lradc = input_get_drvdata(dev); int error; error = regulator_enable(lradc->vref_supply); if (error) return error; lradc->vref = regulator_get_voltage(lradc->vref_supply) * lradc->variant->divisor_numerator / lradc->variant->divisor_denominator; /* * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to * stabilize on press, wait (1 + 1) * 4 ms for key release */ writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) | SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL); writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC); return 0; } static void sun4i_lradc_close(struct input_dev *dev) { struct sun4i_lradc_data *lradc = input_get_drvdata(dev); /* Disable lradc, leave other settings unchanged */ writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) | SAMPLE_RATE(2), lradc->base + LRADC_CTRL); writel(0, lradc->base + LRADC_INTC); regulator_disable(lradc->vref_supply); } static int sun4i_lradc_load_dt_keymap(struct device *dev, struct sun4i_lradc_data *lradc) { struct device_node *np, *pp; int i; int error; np = dev->of_node; if (!np) return -EINVAL; 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; } lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count, sizeof(struct sun4i_lradc_keymap), GFP_KERNEL); if (!lradc->chan0_map) return -ENOMEM; i = 0; for_each_child_of_node(np, pp) { struct sun4i_lradc_keymap *map = &lradc->chan0_map[i]; u32 channel; error = of_property_read_u32(pp, "channel", &channel); if (error || channel != 0) { dev_err(dev, "%pOFn: Inval channel prop\n", pp); of_node_put(pp); return -EINVAL; } error = of_property_read_u32(pp, "voltage", &map->voltage); if (error) { dev_err(dev, "%pOFn: Inval voltage prop\n", pp); of_node_put(pp); return -EINVAL; } error = of_property_read_u32(pp, "linux,code", &map->keycode); if (error) { dev_err(dev, "%pOFn: Inval linux,code prop\n", pp); of_node_put(pp); return -EINVAL; } i++; } return 0; } static int sun4i_lradc_probe(struct platform_device *pdev) { struct sun4i_lradc_data *lradc; struct device *dev = &pdev->dev; int i; int error; lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL); if (!lradc) return -ENOMEM; error = sun4i_lradc_load_dt_keymap(dev, lradc); if (error) return error; lradc->variant = of_device_get_match_data(&pdev->dev); if (!lradc->variant) { dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n"); return -EINVAL; } lradc->vref_supply = devm_regulator_get(dev, "vref"); if (IS_ERR(lradc->vref_supply)) return PTR_ERR(lradc->vref_supply); lradc->dev = dev; lradc->input = devm_input_allocate_device(dev); if (!lradc->input) return -ENOMEM; lradc->input->name = pdev->name; lradc->input->phys = "sun4i_lradc/input0"; lradc->input->open = sun4i_lradc_open; lradc->input->close = sun4i_lradc_close; lradc->input->id.bustype = BUS_HOST; lradc->input->id.vendor = 0x0001; lradc->input->id.product = 0x0001; lradc->input->id.version = 0x0100; __set_bit(EV_KEY, lradc->input->evbit); for (i = 0; i < lradc->chan0_map_count; i++) __set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit); input_set_drvdata(lradc->input, lradc); lradc->base = devm_ioremap_resource(dev, platform_get_resource(pdev, IORESOURCE_MEM, 0)); if (IS_ERR(lradc->base)) return PTR_ERR(lradc->base); error = devm_request_irq(dev, platform_get_irq(pdev, 0), sun4i_lradc_irq, 0, "sun4i-a10-lradc-keys", lradc); if (error) return error; error = input_register_device(lradc->input); if (error) return error; return 0; } static const struct of_device_id sun4i_lradc_of_match[] = { { .compatible = "allwinner,sun4i-a10-lradc-keys", .data = &lradc_variant_a10 }, { .compatible = "allwinner,sun8i-a83t-r-lradc", .data = &r_lradc_variant_a83t }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match); static struct platform_driver sun4i_lradc_driver = { .driver = { .name = "sun4i-a10-lradc-keys", .of_match_table = of_match_ptr(sun4i_lradc_of_match), }, .probe = sun4i_lradc_probe, }; module_platform_driver(sun4i_lradc_driver); MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver"); MODULE_AUTHOR("Hans de Goede "); MODULE_LICENSE("GPL");