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