drivers/video/fbdev/amba-clcd-nomadik.c

   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
  13 static struct gpio_desc *grestb;
  14 static struct gpio_desc *scen;
  15 static struct gpio_desc *scl;
  16 static struct gpio_desc *sda;
  17
  18 static 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
  93 static u8 tpg110_read_reg(u8 address)
  94 {
  95         return tpg110_readwrite_reg(false, address, 0);
  96 }
  97
  98 static void tpg110_write_reg(u8 address, u8 outval)
  99 {
 100         tpg110_readwrite_reg(true, address, outval);
 101 }
 102
 103 static 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
 154 static 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
 171 static 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
 182 static 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
 216 int 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 }
 226 EXPORT_SYMBOL_GPL(nomadik_clcd_init_panel);
 227
 228 #define PMU_CTRL_OFFSET 0x0000
 229 #define PMU_CTRL_LCDNDIF BIT(26)
 230
 231 int 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 }
 251 EXPORT_SYMBOL_GPL(nomadik_clcd_init_board);