432 lines
11 KiB
C
432 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2019 David Lechner <david@lechnology.com>
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*
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* Counter driver for Texas Instruments Enhanced Quadrature Encoder Pulse (eQEP)
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*/
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#include <linux/bitops.h>
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#include <linux/counter.h>
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#include <linux/kernel.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/regmap.h>
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/* 32-bit registers */
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#define QPOSCNT 0x0
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#define QPOSINIT 0x4
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#define QPOSMAX 0x8
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#define QPOSCMP 0xc
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#define QPOSILAT 0x10
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#define QPOSSLAT 0x14
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#define QPOSLAT 0x18
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#define QUTMR 0x1c
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#define QUPRD 0x20
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/* 16-bit registers */
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#define QWDTMR 0x0 /* 0x24 */
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#define QWDPRD 0x2 /* 0x26 */
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#define QDECCTL 0x4 /* 0x28 */
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#define QEPCTL 0x6 /* 0x2a */
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#define QCAPCTL 0x8 /* 0x2c */
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#define QPOSCTL 0xa /* 0x2e */
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#define QEINT 0xc /* 0x30 */
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#define QFLG 0xe /* 0x32 */
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#define QCLR 0x10 /* 0x34 */
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#define QFRC 0x12 /* 0x36 */
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#define QEPSTS 0x14 /* 0x38 */
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#define QCTMR 0x16 /* 0x3a */
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#define QCPRD 0x18 /* 0x3c */
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#define QCTMRLAT 0x1a /* 0x3e */
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#define QCPRDLAT 0x1c /* 0x40 */
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#define QDECCTL_QSRC_SHIFT 14
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#define QDECCTL_QSRC GENMASK(15, 14)
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#define QDECCTL_SOEN BIT(13)
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#define QDECCTL_SPSEL BIT(12)
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#define QDECCTL_XCR BIT(11)
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#define QDECCTL_SWAP BIT(10)
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#define QDECCTL_IGATE BIT(9)
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#define QDECCTL_QAP BIT(8)
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#define QDECCTL_QBP BIT(7)
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#define QDECCTL_QIP BIT(6)
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#define QDECCTL_QSP BIT(5)
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#define QEPCTL_FREE_SOFT GENMASK(15, 14)
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#define QEPCTL_PCRM GENMASK(13, 12)
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#define QEPCTL_SEI GENMASK(11, 10)
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#define QEPCTL_IEI GENMASK(9, 8)
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#define QEPCTL_SWI BIT(7)
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#define QEPCTL_SEL BIT(6)
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#define QEPCTL_IEL GENMASK(5, 4)
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#define QEPCTL_PHEN BIT(3)
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#define QEPCTL_QCLM BIT(2)
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#define QEPCTL_UTE BIT(1)
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#define QEPCTL_WDE BIT(0)
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/* EQEP Inputs */
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enum {
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TI_EQEP_SIGNAL_QEPA, /* QEPA/XCLK */
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TI_EQEP_SIGNAL_QEPB, /* QEPB/XDIR */
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};
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/* Position Counter Input Modes */
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enum {
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TI_EQEP_COUNT_FUNC_QUAD_COUNT,
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TI_EQEP_COUNT_FUNC_DIR_COUNT,
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TI_EQEP_COUNT_FUNC_UP_COUNT,
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TI_EQEP_COUNT_FUNC_DOWN_COUNT,
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};
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enum {
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TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES,
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TI_EQEP_SYNAPSE_ACTION_RISING_EDGE,
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TI_EQEP_SYNAPSE_ACTION_NONE,
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};
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struct ti_eqep_cnt {
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struct counter_device counter;
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struct regmap *regmap32;
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struct regmap *regmap16;
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};
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static int ti_eqep_count_read(struct counter_device *counter,
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struct counter_count *count, unsigned long *val)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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u32 cnt;
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regmap_read(priv->regmap32, QPOSCNT, &cnt);
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*val = cnt;
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return 0;
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}
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static int ti_eqep_count_write(struct counter_device *counter,
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struct counter_count *count, unsigned long val)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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u32 max;
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regmap_read(priv->regmap32, QPOSMAX, &max);
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if (val > max)
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return -EINVAL;
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return regmap_write(priv->regmap32, QPOSCNT, val);
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}
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static int ti_eqep_function_get(struct counter_device *counter,
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struct counter_count *count, size_t *function)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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u32 qdecctl;
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regmap_read(priv->regmap16, QDECCTL, &qdecctl);
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*function = (qdecctl & QDECCTL_QSRC) >> QDECCTL_QSRC_SHIFT;
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return 0;
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}
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static int ti_eqep_function_set(struct counter_device *counter,
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struct counter_count *count, size_t function)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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return regmap_write_bits(priv->regmap16, QDECCTL, QDECCTL_QSRC,
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function << QDECCTL_QSRC_SHIFT);
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}
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static int ti_eqep_action_get(struct counter_device *counter,
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struct counter_count *count,
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struct counter_synapse *synapse, size_t *action)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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size_t function;
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u32 qdecctl;
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int err;
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err = ti_eqep_function_get(counter, count, &function);
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if (err)
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return err;
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switch (function) {
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case TI_EQEP_COUNT_FUNC_QUAD_COUNT:
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/* In quadrature mode, the rising and falling edge of both
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* QEPA and QEPB trigger QCLK.
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*/
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*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
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break;
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case TI_EQEP_COUNT_FUNC_DIR_COUNT:
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/* In direction-count mode only rising edge of QEPA is counted
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* and QEPB gives direction.
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*/
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switch (synapse->signal->id) {
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case TI_EQEP_SIGNAL_QEPA:
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*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
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break;
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default:
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*action = TI_EQEP_SYNAPSE_ACTION_NONE;
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break;
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}
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break;
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case TI_EQEP_COUNT_FUNC_UP_COUNT:
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case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
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/* In up/down-count modes only QEPA is counted and QEPB is not
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* used.
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*/
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switch (synapse->signal->id) {
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case TI_EQEP_SIGNAL_QEPA:
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err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
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if (err)
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return err;
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if (qdecctl & QDECCTL_XCR)
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*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
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else
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*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
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break;
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default:
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*action = TI_EQEP_SYNAPSE_ACTION_NONE;
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break;
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}
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break;
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}
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return 0;
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}
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static const struct counter_ops ti_eqep_counter_ops = {
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.count_read = ti_eqep_count_read,
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.count_write = ti_eqep_count_write,
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.function_get = ti_eqep_function_get,
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.function_set = ti_eqep_function_set,
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.action_get = ti_eqep_action_get,
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};
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static ssize_t ti_eqep_position_ceiling_read(struct counter_device *counter,
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struct counter_count *count,
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void *ext_priv, char *buf)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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u32 qposmax;
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regmap_read(priv->regmap32, QPOSMAX, &qposmax);
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return sprintf(buf, "%u\n", qposmax);
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}
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static ssize_t ti_eqep_position_ceiling_write(struct counter_device *counter,
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struct counter_count *count,
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void *ext_priv, const char *buf,
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size_t len)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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int err;
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u32 res;
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err = kstrtouint(buf, 0, &res);
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if (err < 0)
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return err;
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regmap_write(priv->regmap32, QPOSMAX, res);
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return len;
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}
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static ssize_t ti_eqep_position_enable_read(struct counter_device *counter,
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struct counter_count *count,
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void *ext_priv, char *buf)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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u32 qepctl;
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regmap_read(priv->regmap16, QEPCTL, &qepctl);
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return sprintf(buf, "%u\n", !!(qepctl & QEPCTL_PHEN));
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}
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static ssize_t ti_eqep_position_enable_write(struct counter_device *counter,
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struct counter_count *count,
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void *ext_priv, const char *buf,
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size_t len)
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{
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struct ti_eqep_cnt *priv = counter->priv;
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int err;
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bool res;
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err = kstrtobool(buf, &res);
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if (err < 0)
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return err;
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regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, res ? -1 : 0);
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return len;
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}
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static struct counter_count_ext ti_eqep_position_ext[] = {
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{
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.name = "ceiling",
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.read = ti_eqep_position_ceiling_read,
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.write = ti_eqep_position_ceiling_write,
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},
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{
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.name = "enable",
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.read = ti_eqep_position_enable_read,
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.write = ti_eqep_position_enable_write,
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},
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};
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static struct counter_signal ti_eqep_signals[] = {
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[TI_EQEP_SIGNAL_QEPA] = {
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.id = TI_EQEP_SIGNAL_QEPA,
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.name = "QEPA"
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},
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[TI_EQEP_SIGNAL_QEPB] = {
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.id = TI_EQEP_SIGNAL_QEPB,
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.name = "QEPB"
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},
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};
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static const enum counter_count_function ti_eqep_position_functions[] = {
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[TI_EQEP_COUNT_FUNC_QUAD_COUNT] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
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[TI_EQEP_COUNT_FUNC_DIR_COUNT] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
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[TI_EQEP_COUNT_FUNC_UP_COUNT] = COUNTER_COUNT_FUNCTION_INCREASE,
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[TI_EQEP_COUNT_FUNC_DOWN_COUNT] = COUNTER_COUNT_FUNCTION_DECREASE,
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};
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static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
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[TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
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[TI_EQEP_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
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[TI_EQEP_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
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};
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static struct counter_synapse ti_eqep_position_synapses[] = {
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{
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.actions_list = ti_eqep_position_synapse_actions,
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.num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions),
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.signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPA],
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},
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{
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.actions_list = ti_eqep_position_synapse_actions,
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.num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions),
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.signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPB],
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},
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};
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static struct counter_count ti_eqep_counts[] = {
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{
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.id = 0,
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.name = "QPOSCNT",
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.functions_list = ti_eqep_position_functions,
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.num_functions = ARRAY_SIZE(ti_eqep_position_functions),
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.synapses = ti_eqep_position_synapses,
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.num_synapses = ARRAY_SIZE(ti_eqep_position_synapses),
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.ext = ti_eqep_position_ext,
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.num_ext = ARRAY_SIZE(ti_eqep_position_ext),
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},
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};
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static const struct regmap_config ti_eqep_regmap32_config = {
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.name = "32-bit",
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.reg_bits = 32,
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.val_bits = 32,
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.reg_stride = 4,
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.max_register = QUPRD,
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};
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static const struct regmap_config ti_eqep_regmap16_config = {
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.name = "16-bit",
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.reg_bits = 16,
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.val_bits = 16,
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.reg_stride = 2,
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.max_register = QCPRDLAT,
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};
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static int ti_eqep_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct ti_eqep_cnt *priv;
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void __iomem *base;
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int err;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(base))
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return PTR_ERR(base);
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priv->regmap32 = devm_regmap_init_mmio(dev, base,
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&ti_eqep_regmap32_config);
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if (IS_ERR(priv->regmap32))
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return PTR_ERR(priv->regmap32);
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priv->regmap16 = devm_regmap_init_mmio(dev, base + 0x24,
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&ti_eqep_regmap16_config);
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if (IS_ERR(priv->regmap16))
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return PTR_ERR(priv->regmap16);
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priv->counter.name = dev_name(dev);
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priv->counter.parent = dev;
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priv->counter.ops = &ti_eqep_counter_ops;
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priv->counter.counts = ti_eqep_counts;
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priv->counter.num_counts = ARRAY_SIZE(ti_eqep_counts);
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priv->counter.signals = ti_eqep_signals;
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priv->counter.num_signals = ARRAY_SIZE(ti_eqep_signals);
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priv->counter.priv = priv;
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platform_set_drvdata(pdev, priv);
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/*
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* Need to make sure power is turned on. On AM33xx, this comes from the
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* parent PWMSS bus driver. On AM17xx, this comes from the PSC power
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* domain.
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*/
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pm_runtime_enable(dev);
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pm_runtime_get_sync(dev);
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err = counter_register(&priv->counter);
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if (err < 0) {
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pm_runtime_put_sync(dev);
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pm_runtime_disable(dev);
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return err;
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}
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return 0;
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}
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static int ti_eqep_remove(struct platform_device *pdev)
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{
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struct ti_eqep_cnt *priv = platform_get_drvdata(pdev);
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struct device *dev = &pdev->dev;
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counter_unregister(&priv->counter);
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pm_runtime_put_sync(dev);
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pm_runtime_disable(dev);
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return 0;
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}
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static const struct of_device_id ti_eqep_of_match[] = {
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{ .compatible = "ti,am3352-eqep", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, ti_eqep_of_match);
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static struct platform_driver ti_eqep_driver = {
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.probe = ti_eqep_probe,
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.remove = ti_eqep_remove,
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.driver = {
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.name = "ti-eqep-cnt",
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.of_match_table = ti_eqep_of_match,
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},
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};
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module_platform_driver(ti_eqep_driver);
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MODULE_AUTHOR("David Lechner <david@lechnology.com>");
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MODULE_DESCRIPTION("TI eQEP counter driver");
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MODULE_LICENSE("GPL v2");
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