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![Samuel Holland](/assets/img/avatar_default.png)
This LRADC variant uses the same 3/4*AVCC reference voltage as the A83T variant. The R329 and D1 LRADCs appear to be identical, so D1 support is accomplished through having the R329 LRADC as a fallback compatible. Signed-off-by: Samuel Holland <samuel@sholland.org> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Link: https://lore.kernel.org/r/20220414002349.24332-3-samuel@sholland.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
364 lines
9.4 KiB
C
364 lines
9.4 KiB
C
// 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 <hdegoede@redhat.com>
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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/clk.h>
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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/pm_wakeirq.h>
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#include <linux/pm_wakeup.h>
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#include <linux/regulator/consumer.h>
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#include <linux/reset.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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* @has_clock_reset: If the binding requires a clock and reset
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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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bool has_clock_reset;
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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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static const struct lradc_variant lradc_variant_r329 = {
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.divisor_numerator = 3,
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.divisor_denominator = 4,
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.has_clock_reset = true,
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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 clk *clk;
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struct reset_control *reset;
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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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error = reset_control_deassert(lradc->reset);
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if (error)
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goto err_disable_reg;
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error = clk_prepare_enable(lradc->clk);
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if (error)
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goto err_assert_reset;
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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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err_assert_reset:
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reset_control_assert(lradc->reset);
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err_disable_reg:
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regulator_disable(lradc->vref_supply);
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return error;
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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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clk_disable_unprepare(lradc->clk);
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reset_control_assert(lradc->reset);
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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 error, i, irq;
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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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if (lradc->variant->has_clock_reset) {
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lradc->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(lradc->clk))
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return PTR_ERR(lradc->clk);
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lradc->reset = devm_reset_control_get_exclusive(dev, NULL);
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if (IS_ERR(lradc->reset))
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return PTR_ERR(lradc->reset);
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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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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return irq;
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error = devm_request_irq(dev, irq, 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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if (device_property_read_bool(dev, "wakeup-source")) {
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error = dev_pm_set_wake_irq(dev, irq);
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if (error)
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dev_warn(dev,
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"Failed to set IRQ %d as a wake IRQ: %d\n",
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irq, error);
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else
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device_set_wakeup_capable(dev, true);
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}
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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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{ .compatible = "allwinner,sun50i-r329-lradc",
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.data = &lradc_variant_r329 },
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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 <hdegoede@redhat.com>");
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MODULE_LICENSE("GPL");
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