346 lines
9.0 KiB
C
346 lines
9.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* wm9705.c -- Codec driver for Wolfson WM9705 AC97 Codec.
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*
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* Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
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* Author: Liam Girdwood <lrg@slimlogic.co.uk>
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* Parts Copyright : Ian Molton <spyro@f2s.com>
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* Andrew Zabolotny <zap@homelink.ru>
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* Russell King <rmk@arm.linux.org.uk>
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/kernel.h>
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#include <linux/input.h>
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#include <linux/delay.h>
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#include <linux/bitops.h>
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#include <linux/wm97xx.h>
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#define TS_NAME "wm97xx"
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#define WM9705_VERSION "1.00"
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#define DEFAULT_PRESSURE 0xb0c0
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/*
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* Module parameters
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*/
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/*
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* Set current used for pressure measurement.
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*
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* Set pil = 2 to use 400uA
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* pil = 1 to use 200uA and
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* pil = 0 to disable pressure measurement.
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*
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* This is used to increase the range of values returned by the adc
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* when measureing touchpanel pressure.
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*/
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static int pil;
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module_param(pil, int, 0);
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MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
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/*
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* Set threshold for pressure measurement.
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*
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* Pen down pressure below threshold is ignored.
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*/
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static int pressure = DEFAULT_PRESSURE & 0xfff;
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module_param(pressure, int, 0);
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MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
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/*
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* Set adc sample delay.
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*
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* For accurate touchpanel measurements, some settling time may be
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* required between the switch matrix applying a voltage across the
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* touchpanel plate and the ADC sampling the signal.
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*
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* This delay can be set by setting delay = n, where n is the array
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* position of the delay in the array delay_table below.
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* Long delays > 1ms are supported for completeness, but are not
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* recommended.
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*/
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static int delay = 4;
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module_param(delay, int, 0);
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MODULE_PARM_DESC(delay, "Set adc sample delay.");
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/*
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* Pen detect comparator threshold.
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*
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* 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
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* i.e. 1 = Vmid/15 threshold
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* 15 = Vmid/1 threshold
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*
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* Adjust this value if you are having problems with pen detect not
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* detecting any down events.
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*/
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static int pdd = 8;
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module_param(pdd, int, 0);
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MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");
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/*
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* Set adc mask function.
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*
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* Sources of glitch noise, such as signals driving an LCD display, may feed
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* through to the touch screen plates and affect measurement accuracy. In
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* order to minimise this, a signal may be applied to the MASK pin to delay or
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* synchronise the sampling.
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*
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* 0 = No delay or sync
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* 1 = High on pin stops conversions
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* 2 = Edge triggered, edge on pin delays conversion by delay param (above)
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* 3 = Edge triggered, edge on pin starts conversion after delay param
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*/
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static int mask;
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module_param(mask, int, 0);
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MODULE_PARM_DESC(mask, "Set adc mask function.");
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/*
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* ADC sample delay times in uS
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*/
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static const int delay_table[] = {
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21, /* 1 AC97 Link frames */
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42, /* 2 */
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84, /* 4 */
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167, /* 8 */
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333, /* 16 */
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667, /* 32 */
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1000, /* 48 */
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1333, /* 64 */
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2000, /* 96 */
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2667, /* 128 */
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3333, /* 160 */
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4000, /* 192 */
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4667, /* 224 */
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5333, /* 256 */
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6000, /* 288 */
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0 /* No delay, switch matrix always on */
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};
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/*
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* Delay after issuing a POLL command.
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*
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* The delay is 3 AC97 link frames + the touchpanel settling delay
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*/
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static inline void poll_delay(int d)
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{
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udelay(3 * AC97_LINK_FRAME + delay_table[d]);
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}
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/*
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* set up the physical settings of the WM9705
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*/
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static void wm9705_phy_init(struct wm97xx *wm)
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{
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u16 dig1 = 0, dig2 = WM97XX_RPR;
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/*
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* mute VIDEO and AUX as they share X and Y touchscreen
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* inputs on the WM9705
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*/
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wm97xx_reg_write(wm, AC97_AUX, 0x8000);
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wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);
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/* touchpanel pressure current*/
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if (pil == 2) {
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dig2 |= WM9705_PIL;
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dev_dbg(wm->dev,
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"setting pressure measurement current to 400uA.");
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} else if (pil)
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dev_dbg(wm->dev,
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"setting pressure measurement current to 200uA.");
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if (!pil)
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pressure = 0;
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/* polling mode sample settling delay */
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if (delay != 4) {
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if (delay < 0 || delay > 15) {
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dev_dbg(wm->dev, "supplied delay out of range.");
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delay = 4;
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}
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}
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dig1 &= 0xff0f;
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dig1 |= WM97XX_DELAY(delay);
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dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
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delay_table[delay]);
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/* WM9705 pdd */
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dig2 |= (pdd & 0x000f);
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dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));
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/* mask */
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dig2 |= ((mask & 0x3) << 4);
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
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}
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static void wm9705_dig_enable(struct wm97xx *wm, int enable)
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{
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if (enable) {
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
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wm->dig[2] | WM97XX_PRP_DET_DIG);
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wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
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} else
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
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wm->dig[2] & ~WM97XX_PRP_DET_DIG);
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}
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static void wm9705_aux_prepare(struct wm97xx *wm)
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{
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memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
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}
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static void wm9705_dig_restore(struct wm97xx *wm)
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{
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
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}
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static inline int is_pden(struct wm97xx *wm)
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{
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return wm->dig[2] & WM9705_PDEN;
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}
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/*
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* Read a sample from the WM9705 adc in polling mode.
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*/
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static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
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{
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int timeout = 5 * delay;
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bool wants_pen = adcsel & WM97XX_PEN_DOWN;
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if (wants_pen && !wm->pen_probably_down) {
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u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
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if (!(data & WM97XX_PEN_DOWN))
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return RC_PENUP;
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wm->pen_probably_down = 1;
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}
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/* set up digitiser */
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if (wm->mach_ops && wm->mach_ops->pre_sample)
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wm->mach_ops->pre_sample(adcsel);
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
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| WM97XX_POLL | WM97XX_DELAY(delay));
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/* wait 3 AC97 time slots + delay for conversion */
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poll_delay(delay);
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/* wait for POLL to go low */
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while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
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&& timeout) {
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udelay(AC97_LINK_FRAME);
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timeout--;
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}
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if (timeout == 0) {
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/* If PDEN is set, we can get a timeout when pen goes up */
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if (is_pden(wm))
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wm->pen_probably_down = 0;
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else
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dev_dbg(wm->dev, "adc sample timeout");
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return RC_PENUP;
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}
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*sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
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if (wm->mach_ops && wm->mach_ops->post_sample)
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wm->mach_ops->post_sample(adcsel);
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/* check we have correct sample */
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if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
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dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
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adcsel & WM97XX_ADCSEL_MASK,
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*sample & WM97XX_ADCSEL_MASK);
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return RC_PENUP;
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}
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if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
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wm->pen_probably_down = 0;
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return RC_PENUP;
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}
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return RC_VALID;
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}
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/*
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* Sample the WM9705 touchscreen in polling mode
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*/
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static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
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{
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int rc;
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rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
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if (rc != RC_VALID)
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return rc;
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rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
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if (rc != RC_VALID)
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return rc;
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if (pil) {
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rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN, &data->p);
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if (rc != RC_VALID)
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return rc;
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} else
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data->p = DEFAULT_PRESSURE;
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return RC_VALID;
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}
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/*
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* Enable WM9705 continuous mode, i.e. touch data is streamed across
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* an AC97 slot
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*/
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static int wm9705_acc_enable(struct wm97xx *wm, int enable)
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{
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u16 dig1, dig2;
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int ret = 0;
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dig1 = wm->dig[1];
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dig2 = wm->dig[2];
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if (enable) {
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/* continuous mode */
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if (wm->mach_ops->acc_startup &&
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(ret = wm->mach_ops->acc_startup(wm)) < 0)
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return ret;
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dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
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WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
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dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
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WM97XX_DELAY(delay) |
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WM97XX_SLT(wm->acc_slot) |
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WM97XX_RATE(wm->acc_rate);
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if (pil)
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dig1 |= WM97XX_ADCSEL_PRES;
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dig2 |= WM9705_PDEN;
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} else {
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dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
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dig2 &= ~WM9705_PDEN;
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if (wm->mach_ops->acc_shutdown)
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wm->mach_ops->acc_shutdown(wm);
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}
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
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wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
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return ret;
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}
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struct wm97xx_codec_drv wm9705_codec = {
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.id = WM9705_ID2,
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.name = "wm9705",
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.poll_sample = wm9705_poll_sample,
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.poll_touch = wm9705_poll_touch,
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.acc_enable = wm9705_acc_enable,
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.phy_init = wm9705_phy_init,
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.dig_enable = wm9705_dig_enable,
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.dig_restore = wm9705_dig_restore,
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.aux_prepare = wm9705_aux_prepare,
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};
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EXPORT_SYMBOL_GPL(wm9705_codec);
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/* Module information */
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MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
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MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
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MODULE_LICENSE("GPL");
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