diff options
Diffstat (limited to 'drivers/input/keyboard/sun4i-lradc-keys.c')
| -rw-r--r-- | drivers/input/keyboard/sun4i-lradc-keys.c | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c new file mode 100644 index 000000000..4a796bed4 --- /dev/null +++ b/drivers/input/keyboard/sun4i-lradc-keys.c @@ -0,0 +1,309 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Allwinner sun4i low res adc attached tablet keys driver + * + * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.com> + */ + +/* + * 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 <linux/err.h> +#include <linux/init.h> +#include <linux/input.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> + +#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 <hdegoede@redhat.com>"); +MODULE_LICENSE("GPL"); |