LXR linux/drivers/staging/olpc_dcon/olpc_dcon_xo

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
   4 *
   5 * Copyright © 2006-2007  Red Hat, Inc.
   6 * Copyright © 2006-2007  Advanced Micro Devices, Inc.
   7 * Copyright © 2009       VIA Technology, Inc.
   8 * Copyright (c) 2010  Andres Salomon <dilinger@queued.net>
   9 */
  10
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13#include <linux/cs5535.h>
  14#include <linux/gpio/consumer.h>
  15#include <linux/delay.h>
  16#include <linux/i2c.h>
  17#include <asm/olpc.h>
  18
  19#include "olpc_dcon.h"
  20
  21enum dcon_gpios {
  22        OLPC_DCON_STAT0,
  23        OLPC_DCON_STAT1,
  24        OLPC_DCON_IRQ,
  25        OLPC_DCON_LOAD,
  26        OLPC_DCON_BLANK,
  27};
  28
  29static const struct dcon_gpio gpios_asis[] = {
  30        [OLPC_DCON_STAT0] = { .name = "dcon_stat0", .flags = GPIOD_ASIS },
  31        [OLPC_DCON_STAT1] = { .name = "dcon_stat1", .flags = GPIOD_ASIS },
  32        [OLPC_DCON_IRQ] = { .name = "dcon_irq", .flags = GPIOD_ASIS },
  33        [OLPC_DCON_LOAD] = { .name = "dcon_load", .flags = GPIOD_ASIS },
  34        [OLPC_DCON_BLANK] = { .name = "dcon_blank", .flags = GPIOD_ASIS },
  35};
  36
  37static struct gpio_desc *gpios[5];
  38
  39static int dcon_init_xo_1(struct dcon_priv *dcon)
  40{
  41        unsigned char lob;
  42        int ret, i;
  43        const struct dcon_gpio *pin = &gpios_asis[0];
  44
  45        for (i = 0; i < ARRAY_SIZE(gpios_asis); i++) {
  46                gpios[i] = devm_gpiod_get(&dcon->client->dev, pin[i].name,
  47                                          pin[i].flags);
  48                if (IS_ERR(gpios[i])) {
  49                        ret = PTR_ERR(gpios[i]);
  50                        pr_err("failed to request %s GPIO: %d\n", pin[i].name,
  51                               ret);
  52                        return ret;
  53                }
  54        }
  55
  56        /* Turn off the event enable for GPIO7 just to be safe */
  57        cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_EVENTS_ENABLE);
  58
  59        /*
  60         * Determine the current state by reading the GPIO bit; earlier
  61         * stages of the boot process have established the state.
  62         *
  63         * Note that we read GPIO_OUTPUT_VAL rather than GPIO_READ_BACK here;
  64         * this is because OFW will disable input for the pin and set a value..
  65         * READ_BACK will only contain a valid value if input is enabled and
  66         * then a value is set.  So, future readings of the pin can use
  67         * READ_BACK, but the first one cannot.  Awesome, huh?
  68         */
  69        dcon->curr_src = cs5535_gpio_isset(OLPC_GPIO_DCON_LOAD, GPIO_OUTPUT_VAL)
  70                ? DCON_SOURCE_CPU
  71                : DCON_SOURCE_DCON;
  72        dcon->pending_src = dcon->curr_src;
  73
  74        /* Set the directions for the GPIO pins */
  75        gpiod_direction_input(gpios[OLPC_DCON_STAT0]);
  76        gpiod_direction_input(gpios[OLPC_DCON_STAT1]);
  77        gpiod_direction_input(gpios[OLPC_DCON_IRQ]);
  78        gpiod_direction_input(gpios[OLPC_DCON_BLANK]);
  79        gpiod_direction_output(gpios[OLPC_DCON_LOAD],
  80                               dcon->curr_src == DCON_SOURCE_CPU);
  81
  82        /* Set up the interrupt mappings */
  83
  84        /* Set the IRQ to pair 2 */
  85        cs5535_gpio_setup_event(OLPC_GPIO_DCON_IRQ, 2, 0);
  86
  87        /* Enable group 2 to trigger the DCON interrupt */
  88        cs5535_gpio_set_irq(2, DCON_IRQ);
  89
  90        /* Select edge level for interrupt (in PIC) */
  91        lob = inb(0x4d0);
  92        lob &= ~(1 << DCON_IRQ);
  93        outb(lob, 0x4d0);
  94
  95        /* Register the interrupt handler */
  96        if (request_irq(DCON_IRQ, &dcon_interrupt, 0, "DCON", dcon)) {
  97                pr_err("failed to request DCON's irq\n");
  98                return -EIO;
  99        }
 100
 101        /* Clear INV_EN for GPIO7 (DCONIRQ) */
 102        cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_INPUT_INVERT);
 103
 104        /* Enable filter for GPIO12 (DCONBLANK) */
 105        cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_INPUT_FILTER);
 106
 107        /* Disable filter for GPIO7 */
 108        cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_INPUT_FILTER);
 109
 110        /* Disable event counter for GPIO7 (DCONIRQ) and GPIO12 (DCONBLANK) */
 111        cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_INPUT_EVENT_COUNT);
 112        cs5535_gpio_clear(OLPC_GPIO_DCON_BLANK, GPIO_INPUT_EVENT_COUNT);
 113
 114        /* Add GPIO12 to the Filter Event Pair #7 */
 115        cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_FE7_SEL);
 116
 117        /* Turn off negative Edge Enable for GPIO12 */
 118        cs5535_gpio_clear(OLPC_GPIO_DCON_BLANK, GPIO_NEGATIVE_EDGE_EN);
 119
 120        /* Enable negative Edge Enable for GPIO7 */
 121        cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_NEGATIVE_EDGE_EN);
 122
 123        /* Zero the filter amount for Filter Event Pair #7 */
 124        cs5535_gpio_set(0, GPIO_FLTR7_AMOUNT);
 125
 126        /* Clear the negative edge status for GPIO7 and GPIO12 */
 127        cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_NEGATIVE_EDGE_STS);
 128        cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_NEGATIVE_EDGE_STS);
 129
 130        /* FIXME:  Clear the positive status as well, just to be sure */
 131        cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_POSITIVE_EDGE_STS);
 132        cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_POSITIVE_EDGE_STS);
 133
 134        /* Enable events for GPIO7 (DCONIRQ) and GPIO12 (DCONBLANK) */
 135        cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_EVENTS_ENABLE);
 136        cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_EVENTS_ENABLE);
 137
 138        return 0;
 139}
 140
 141static void dcon_wiggle_xo_1(void)
 142{
 143        int x;
 144
 145        /*
 146         * According to HiMax, when powering the DCON up we should hold
 147         * SMB_DATA high for 8 SMB_CLK cycles.  This will force the DCON
 148         * state machine to reset to a (sane) initial state.  Mitch Bradley
 149         * did some testing and discovered that holding for 16 SMB_CLK cycles
 150         * worked a lot more reliably, so that's what we do here.
 151         *
 152         * According to the cs5536 spec, to set GPIO14 to SMB_CLK we must
 153         * simultaneously set AUX1 IN/OUT to GPIO14; ditto for SMB_DATA and
 154         * GPIO15.
 155         */
 156        cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_VAL);
 157        cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_VAL);
 158        cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_ENABLE);
 159        cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_ENABLE);
 160        cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_AUX1);
 161        cs5535_gpio_clear(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_AUX1);
 162        cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_AUX2);
 163        cs5535_gpio_clear(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_AUX2);
 164        cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_INPUT_AUX1);
 165        cs5535_gpio_clear(OLPC_GPIO_SMB_DATA, GPIO_INPUT_AUX1);
 166
 167        for (x = 0; x < 16; x++) {
 168                udelay(5);
 169                cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_VAL);
 170                udelay(5);
 171                cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_VAL);
 172        }
 173        udelay(5);
 174        cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_AUX1);
 175        cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_AUX1);
 176        cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_INPUT_AUX1);
 177        cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_INPUT_AUX1);
 178}
 179
 180static void dcon_set_dconload_1(int val)
 181{
 182        gpiod_set_value(gpios[OLPC_DCON_LOAD], val);
 183}
 184
 185static int dcon_read_status_xo_1(u8 *status)
 186{
 187        *status = gpiod_get_value(gpios[OLPC_DCON_STAT0]);
 188        *status |= gpiod_get_value(gpios[OLPC_DCON_STAT1]) << 1;
 189
 190        /* Clear the negative edge status for GPIO7 */
 191        cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_NEGATIVE_EDGE_STS);
 192
 193        return 0;
 194}
 195
 196struct dcon_platform_data dcon_pdata_xo_1 = {
 197        .init = dcon_init_xo_1,
 198        .bus_stabilize_wiggle = dcon_wiggle_xo_1,
 199        .set_dconload = dcon_set_dconload_1,
 200        .read_status = dcon_read_status_xo_1,
 201};
 202