linux/drivers/video/fbdev/amba-clcd-nomadik.c
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   1#include <linux/amba/bus.h>
   2#include <linux/amba/clcd.h>
   3#include <linux/gpio/consumer.h>
   4#include <linux/of.h>
   5#include <linux/of_graph.h>
   6#include <linux/delay.h>
   7#include <linux/bitops.h>
   8#include <linux/mfd/syscon.h>
   9#include <linux/regmap.h>
  10
  11#include "amba-clcd-nomadik.h"
  12
  13static struct gpio_desc *grestb;
  14static struct gpio_desc *scen;
  15static struct gpio_desc *scl;
  16static struct gpio_desc *sda;
  17
  18static u8 tpg110_readwrite_reg(bool write, u8 address, u8 outval)
  19{
  20        int i;
  21        u8 inval = 0;
  22
  23        /* Assert SCEN */
  24        gpiod_set_value_cansleep(scen, 1);
  25        ndelay(150);
  26        /* Hammer out the address */
  27        for (i = 5; i >= 0; i--) {
  28                if (address & BIT(i))
  29                        gpiod_set_value_cansleep(sda, 1);
  30                else
  31                        gpiod_set_value_cansleep(sda, 0);
  32                ndelay(150);
  33                /* Send an SCL pulse */
  34                gpiod_set_value_cansleep(scl, 1);
  35                ndelay(160);
  36                gpiod_set_value_cansleep(scl, 0);
  37                ndelay(160);
  38        }
  39
  40        if (write) {
  41                /* WRITE */
  42                gpiod_set_value_cansleep(sda, 0);
  43        } else {
  44                /* READ */
  45                gpiod_set_value_cansleep(sda, 1);
  46        }
  47        ndelay(150);
  48        /* Send an SCL pulse */
  49        gpiod_set_value_cansleep(scl, 1);
  50        ndelay(160);
  51        gpiod_set_value_cansleep(scl, 0);
  52        ndelay(160);
  53
  54        if (!write)
  55                /* HiZ turn-around cycle */
  56                gpiod_direction_input(sda);
  57        ndelay(150);
  58        /* Send an SCL pulse */
  59        gpiod_set_value_cansleep(scl, 1);
  60        ndelay(160);
  61        gpiod_set_value_cansleep(scl, 0);
  62        ndelay(160);
  63
  64        /* Hammer in/out the data */
  65        for (i = 7; i >= 0; i--) {
  66                int value;
  67
  68                if (write) {
  69                        value = !!(outval & BIT(i));
  70                        gpiod_set_value_cansleep(sda, value);
  71                } else {
  72                        value = gpiod_get_value(sda);
  73                        if (value)
  74                                inval |= BIT(i);
  75                }
  76                ndelay(150);
  77                /* Send an SCL pulse */
  78                gpiod_set_value_cansleep(scl, 1);
  79                ndelay(160);
  80                gpiod_set_value_cansleep(scl, 0);
  81                ndelay(160);
  82        }
  83
  84        gpiod_direction_output(sda, 0);
  85        /* Deassert SCEN */
  86        gpiod_set_value_cansleep(scen, 0);
  87        /* Satisfies SCEN pulse width */
  88        udelay(1);
  89
  90        return inval;
  91}
  92
  93static u8 tpg110_read_reg(u8 address)
  94{
  95        return tpg110_readwrite_reg(false, address, 0);
  96}
  97
  98static void tpg110_write_reg(u8 address, u8 outval)
  99{
 100        tpg110_readwrite_reg(true, address, outval);
 101}
 102
 103static void tpg110_startup(struct device *dev)
 104{
 105        u8 val;
 106
 107        dev_info(dev, "TPG110 display enable\n");
 108        /* De-assert the reset signal */
 109        gpiod_set_value_cansleep(grestb, 0);
 110        mdelay(1);
 111        dev_info(dev, "de-asserted GRESTB\n");
 112
 113        /* Test display communication */
 114        tpg110_write_reg(0x00, 0x55);
 115        val = tpg110_read_reg(0x00);
 116        if (val == 0x55)
 117                dev_info(dev, "passed communication test\n");
 118        val = tpg110_read_reg(0x01);
 119        dev_info(dev, "TPG110 chip ID: %d version: %d\n",
 120                val>>4, val&0x0f);
 121
 122        /* Show display resolution */
 123        val = tpg110_read_reg(0x02);
 124        val &= 7;
 125        switch (val) {
 126        case 0x0:
 127                dev_info(dev, "IN 400x240 RGB -> OUT 800x480 RGB (dual scan)");
 128                break;
 129        case 0x1:
 130                dev_info(dev, "IN 480x272 RGB -> OUT 800x480 RGB (dual scan)");
 131                break;
 132        case 0x4:
 133                dev_info(dev, "480x640 RGB");
 134                break;
 135        case 0x5:
 136                dev_info(dev, "480x272 RGB");
 137                break;
 138        case 0x6:
 139                dev_info(dev, "640x480 RGB");
 140                break;
 141        case 0x7:
 142                dev_info(dev, "800x480 RGB");
 143                break;
 144        default:
 145                dev_info(dev, "ILLEGAL RESOLUTION");
 146                break;
 147        }
 148
 149        val = tpg110_read_reg(0x03);
 150        dev_info(dev, "resolution is controlled by %s\n",
 151                (val & BIT(7)) ? "software" : "hardware");
 152}
 153
 154static void tpg110_enable(struct clcd_fb *fb)
 155{
 156        struct device *dev = &fb->dev->dev;
 157        static bool startup;
 158        u8 val;
 159
 160        if (!startup) {
 161                tpg110_startup(dev);
 162                startup = true;
 163        }
 164
 165        /* Take chip out of standby */
 166        val = tpg110_read_reg(0x03);
 167        val |= BIT(0);
 168        tpg110_write_reg(0x03, val);
 169}
 170
 171static void tpg110_disable(struct clcd_fb *fb)
 172{
 173        u8 val;
 174
 175        dev_info(&fb->dev->dev, "TPG110 display disable\n");
 176        val = tpg110_read_reg(0x03);
 177        /* Put into standby */
 178        val &= ~BIT(0);
 179        tpg110_write_reg(0x03, val);
 180}
 181
 182static void tpg110_init(struct device *dev, struct device_node *np,
 183                        struct clcd_board *board)
 184{
 185        dev_info(dev, "TPG110 display init\n");
 186
 187        /* This asserts the GRESTB signal, putting the display into reset */
 188        grestb = devm_fwnode_get_gpiod_from_child(dev, "grestb", &np->fwnode,
 189                                                  GPIOD_OUT_HIGH, "grestb");
 190        if (IS_ERR(grestb)) {
 191                dev_err(dev, "no GRESTB GPIO\n");
 192                return;
 193        }
 194        scen = devm_fwnode_get_gpiod_from_child(dev, "scen", &np->fwnode,
 195                                                GPIOD_OUT_LOW, "scen");
 196        if (IS_ERR(scen)) {
 197                dev_err(dev, "no SCEN GPIO\n");
 198                return;
 199        }
 200        scl = devm_fwnode_get_gpiod_from_child(dev, "scl", &np->fwnode,
 201                                               GPIOD_OUT_LOW, "scl");
 202        if (IS_ERR(scl)) {
 203                dev_err(dev, "no SCL GPIO\n");
 204                return;
 205        }
 206        sda = devm_fwnode_get_gpiod_from_child(dev, "sda", &np->fwnode,
 207                                               GPIOD_OUT_LOW, "sda");
 208        if (IS_ERR(sda)) {
 209                dev_err(dev, "no SDA GPIO\n");
 210                return;
 211        }
 212        board->enable = tpg110_enable;
 213        board->disable = tpg110_disable;
 214}
 215
 216int nomadik_clcd_init_panel(struct clcd_fb *fb, struct device_node *panel)
 217{
 218        if (of_device_is_compatible(panel, "tpo,tpg110"))
 219                tpg110_init(&fb->dev->dev, panel, fb->board);
 220        else
 221                dev_info(&fb->dev->dev, "unknown panel\n");
 222
 223        /* Unknown panel, fall through */
 224        return 0;
 225}
 226EXPORT_SYMBOL_GPL(nomadik_clcd_init_panel);
 227
 228#define PMU_CTRL_OFFSET 0x0000
 229#define PMU_CTRL_LCDNDIF BIT(26)
 230
 231int nomadik_clcd_init_board(struct amba_device *adev,
 232                            struct clcd_board *board)
 233{
 234        struct regmap *pmu_regmap;
 235
 236        dev_info(&adev->dev, "Nomadik CLCD board init\n");
 237        pmu_regmap =
 238                syscon_regmap_lookup_by_compatible("stericsson,nomadik-pmu");
 239        if (IS_ERR(pmu_regmap)) {
 240                dev_err(&adev->dev, "could not find PMU syscon regmap\n");
 241                return PTR_ERR(pmu_regmap);
 242        }
 243        regmap_update_bits(pmu_regmap,
 244                           PMU_CTRL_OFFSET,
 245                           PMU_CTRL_LCDNDIF,
 246                           0);
 247        dev_info(&adev->dev, "set PMU mux to CLCD mode\n");
 248
 249        return 0;
 250}
 251EXPORT_SYMBOL_GPL(nomadik_clcd_init_board);
 252