drivers/staging/olpc_dcon/olpc_dcon_xo_1.c

   1 /*
   2  * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
   3  *
   4  * Copyright © 2006-2007  Red Hat, Inc.
   5  * Copyright © 2006-2007  Advanced Micro Devices, Inc.
   6  * Copyright © 2009       VIA Technology, Inc.
   7  * Copyright (c) 2010  Andres Salomon <dilinger@queued.net>
   8  *
   9  * This program is free software.  You can redistribute it and/or
  10  * modify it under the terms of version 2 of the GNU General Public
  11  * License as published by the Free Software Foundation.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/cs5535.h>
  17 #include <linux/gpio.h>
  18 #include <linux/delay.h>
  19 #include <asm/olpc.h>
  20
  21 #include "olpc_dcon.h"
  22
  23 static int dcon_init_xo_1(struct dcon_priv *dcon)
  24 {
  25         unsigned char lob;
  26
  27         if (gpio_request(OLPC_GPIO_DCON_STAT0, "OLPC-DCON")) {
  28                 pr_err("failed to request STAT0 GPIO\n");
  29                 return -EIO;
  30         }
  31         if (gpio_request(OLPC_GPIO_DCON_STAT1, "OLPC-DCON")) {
  32                 pr_err("failed to request STAT1 GPIO\n");
  33                 goto err_gp_stat1;
  34         }
  35         if (gpio_request(OLPC_GPIO_DCON_IRQ, "OLPC-DCON")) {
  36                 pr_err("failed to request IRQ GPIO\n");
  37                 goto err_gp_irq;
  38         }
  39         if (gpio_request(OLPC_GPIO_DCON_LOAD, "OLPC-DCON")) {
  40                 pr_err("failed to request LOAD GPIO\n");
  41                 goto err_gp_load;
  42         }
  43         if (gpio_request(OLPC_GPIO_DCON_BLANK, "OLPC-DCON")) {
  44                 pr_err("failed to request BLANK GPIO\n");
  45                 goto err_gp_blank;
  46         }
  47
  48         /* Turn off the event enable for GPIO7 just to be safe */
  49         cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_EVENTS_ENABLE);
  50
  51         /*
  52          * Determine the current state by reading the GPIO bit; earlier
  53          * stages of the boot process have established the state.
  54          *
  55          * Note that we read GPIO_OUPUT_VAL rather than GPIO_READ_BACK here;
  56          * this is because OFW will disable input for the pin and set a value..
  57          * READ_BACK will only contain a valid value if input is enabled and
  58          * then a value is set.  So, future readings of the pin can use
  59          * READ_BACK, but the first one cannot.  Awesome, huh?
  60          */
  61         dcon->curr_src = cs5535_gpio_isset(OLPC_GPIO_DCON_LOAD, GPIO_OUTPUT_VAL)
  62                 ? DCON_SOURCE_CPU
  63                 : DCON_SOURCE_DCON;
  64         dcon->pending_src = dcon->curr_src;
  65
  66         /* Set the directions for the GPIO pins */
  67         gpio_direction_input(OLPC_GPIO_DCON_STAT0);
  68         gpio_direction_input(OLPC_GPIO_DCON_STAT1);
  69         gpio_direction_input(OLPC_GPIO_DCON_IRQ);
  70         gpio_direction_input(OLPC_GPIO_DCON_BLANK);
  71         gpio_direction_output(OLPC_GPIO_DCON_LOAD,
  72                         dcon->curr_src == DCON_SOURCE_CPU);
  73
  74         /* Set up the interrupt mappings */
  75
  76         /* Set the IRQ to pair 2 */
  77         cs5535_gpio_setup_event(OLPC_GPIO_DCON_IRQ, 2, 0);
  78
  79         /* Enable group 2 to trigger the DCON interrupt */
  80         cs5535_gpio_set_irq(2, DCON_IRQ);
  81
  82         /* Select edge level for interrupt (in PIC) */
  83         lob = inb(0x4d0);
  84         lob &= ~(1 << DCON_IRQ);
  85         outb(lob, 0x4d0);
  86
  87         /* Register the interrupt handler */
  88         if (request_irq(DCON_IRQ, &dcon_interrupt, 0, "DCON", dcon)) {
  89                 pr_err("failed to request DCON's irq\n");
  90                 goto err_req_irq;
  91         }
  92
  93         /* Clear INV_EN for GPIO7 (DCONIRQ) */
  94         cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_INPUT_INVERT);
  95
  96         /* Enable filter for GPIO12 (DCONBLANK) */
  97         cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_INPUT_FILTER);
  98
  99         /* Disable filter for GPIO7 */
 100         cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_INPUT_FILTER);
 101
 102         /* Disable event counter for GPIO7 (DCONIRQ) and GPIO12 (DCONBLANK) */
 103         cs5535_gpio_clear(OLPC_GPIO_DCON_IRQ, GPIO_INPUT_EVENT_COUNT);
 104         cs5535_gpio_clear(OLPC_GPIO_DCON_BLANK, GPIO_INPUT_EVENT_COUNT);
 105
 106         /* Add GPIO12 to the Filter Event Pair #7 */
 107         cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_FE7_SEL);
 108
 109         /* Turn off negative Edge Enable for GPIO12 */
 110         cs5535_gpio_clear(OLPC_GPIO_DCON_BLANK, GPIO_NEGATIVE_EDGE_EN);
 111
 112         /* Enable negative Edge Enable for GPIO7 */
 113         cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_NEGATIVE_EDGE_EN);
 114
 115         /* Zero the filter amount for Filter Event Pair #7 */
 116         cs5535_gpio_set(0, GPIO_FLTR7_AMOUNT);
 117
 118         /* Clear the negative edge status for GPIO7 and GPIO12 */
 119         cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_NEGATIVE_EDGE_STS);
 120         cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_NEGATIVE_EDGE_STS);
 121
 122         /* FIXME:  Clear the positive status as well, just to be sure */
 123         cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_POSITIVE_EDGE_STS);
 124         cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_POSITIVE_EDGE_STS);
 125
 126         /* Enable events for GPIO7 (DCONIRQ) and GPIO12 (DCONBLANK) */
 127         cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_EVENTS_ENABLE);
 128         cs5535_gpio_set(OLPC_GPIO_DCON_BLANK, GPIO_EVENTS_ENABLE);
 129
 130         return 0;
 131
 132 err_req_irq:
 133         gpio_free(OLPC_GPIO_DCON_BLANK);
 134 err_gp_blank:
 135         gpio_free(OLPC_GPIO_DCON_LOAD);
 136 err_gp_load:
 137         gpio_free(OLPC_GPIO_DCON_IRQ);
 138 err_gp_irq:
 139         gpio_free(OLPC_GPIO_DCON_STAT1);
 140 err_gp_stat1:
 141         gpio_free(OLPC_GPIO_DCON_STAT0);
 142         return -EIO;
 143 }
 144
 145 static void dcon_wiggle_xo_1(void)
 146 {
 147         int x;
 148
 149         /*
 150          * According to HiMax, when powering the DCON up we should hold
 151          * SMB_DATA high for 8 SMB_CLK cycles.  This will force the DCON
 152          * state machine to reset to a (sane) initial state.  Mitch Bradley
 153          * did some testing and discovered that holding for 16 SMB_CLK cycles
 154          * worked a lot more reliably, so that's what we do here.
 155          *
 156          * According to the cs5536 spec, to set GPIO14 to SMB_CLK we must
 157          * simultaneously set AUX1 IN/OUT to GPIO14; ditto for SMB_DATA and
 158          * GPIO15.
 159          */
 160         cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_VAL);
 161         cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_VAL);
 162         cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_ENABLE);
 163         cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_ENABLE);
 164         cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_AUX1);
 165         cs5535_gpio_clear(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_AUX1);
 166         cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_AUX2);
 167         cs5535_gpio_clear(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_AUX2);
 168         cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_INPUT_AUX1);
 169         cs5535_gpio_clear(OLPC_GPIO_SMB_DATA, GPIO_INPUT_AUX1);
 170
 171         for (x = 0; x < 16; x++) {
 172                 udelay(5);
 173                 cs5535_gpio_clear(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_VAL);
 174                 udelay(5);
 175                 cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_VAL);
 176         }
 177         udelay(5);
 178         cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_OUTPUT_AUX1);
 179         cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_OUTPUT_AUX1);
 180         cs5535_gpio_set(OLPC_GPIO_SMB_CLK, GPIO_INPUT_AUX1);
 181         cs5535_gpio_set(OLPC_GPIO_SMB_DATA, GPIO_INPUT_AUX1);
 182 }
 183
 184 static void dcon_set_dconload_1(int val)
 185 {
 186         gpio_set_value(OLPC_GPIO_DCON_LOAD, val);
 187 }
 188
 189 static int dcon_read_status_xo_1(u8 *status)
 190 {
 191         *status = gpio_get_value(OLPC_GPIO_DCON_STAT0);
 192         *status |= gpio_get_value(OLPC_GPIO_DCON_STAT1) << 1;
 193
 194         /* Clear the negative edge status for GPIO7 */
 195         cs5535_gpio_set(OLPC_GPIO_DCON_IRQ, GPIO_NEGATIVE_EDGE_STS);
 196
 197         return 0;
 198 }
 199
 200 struct dcon_platform_data dcon_pdata_xo_1 = {
 201         .init = dcon_init_xo_1,
 202         .bus_stabilize_wiggle = dcon_wiggle_xo_1,
 203         .set_dconload = dcon_set_dconload_1,
 204         .read_status = dcon_read_status_xo_1,
 205 };