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