drm/radeon/kms: clean up i2c

- Change reg/mask names to match what we use internally
and in the bios
- Clarify how i2c over gpio on radeon actually works

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

5 files changed, 86 insertions, 67 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 2ed88a82093..cd07c0e9122 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -82,18 +82,18 @@ static inline struct radeon_i2c_bus_rec radeon_lookup_gpio(struct drm_device
 
 	i2c.mask_clk_reg = le16_to_cpu(gpio.usClkMaskRegisterIndex) * 4;
 	i2c.mask_data_reg = le16_to_cpu(gpio.usDataMaskRegisterIndex) * 4;
-	i2c.put_clk_reg = le16_to_cpu(gpio.usClkEnRegisterIndex) * 4;
-	i2c.put_data_reg = le16_to_cpu(gpio.usDataEnRegisterIndex) * 4;
-	i2c.get_clk_reg = le16_to_cpu(gpio.usClkY_RegisterIndex) * 4;
-	i2c.get_data_reg = le16_to_cpu(gpio.usDataY_RegisterIndex) * 4;
+	i2c.en_clk_reg = le16_to_cpu(gpio.usClkEnRegisterIndex) * 4;
+	i2c.en_data_reg = le16_to_cpu(gpio.usDataEnRegisterIndex) * 4;
+	i2c.y_clk_reg = le16_to_cpu(gpio.usClkY_RegisterIndex) * 4;
+	i2c.y_data_reg = le16_to_cpu(gpio.usDataY_RegisterIndex) * 4;
 	i2c.a_clk_reg = le16_to_cpu(gpio.usClkA_RegisterIndex) * 4;
 	i2c.a_data_reg = le16_to_cpu(gpio.usDataA_RegisterIndex) * 4;
 	i2c.mask_clk_mask = (1 << gpio.ucClkMaskShift);
 	i2c.mask_data_mask = (1 << gpio.ucDataMaskShift);
-	i2c.put_clk_mask = (1 << gpio.ucClkEnShift);
-	i2c.put_data_mask = (1 << gpio.ucDataEnShift);
-	i2c.get_clk_mask = (1 << gpio.ucClkY_Shift);
-	i2c.get_data_mask = (1 << gpio.ucDataY_Shift);
+	i2c.en_clk_mask = (1 << gpio.ucClkEnShift);
+	i2c.en_data_mask = (1 << gpio.ucDataEnShift);
+	i2c.y_clk_mask = (1 << gpio.ucClkY_Shift);
+	i2c.y_data_mask = (1 << gpio.ucDataY_Shift);
 	i2c.a_clk_mask = (1 << gpio.ucClkA_Shift);
 	i2c.a_data_mask = (1 << gpio.ucDataA_Shift);
 	i2c.valid = true;
diff --git a/drivers/gpu/drm/radeon/radeon_combios.c b/drivers/gpu/drm/radeon/radeon_combios.c
index 5253cbf6db1..e2a51de67aa 100644
--- a/drivers/gpu/drm/radeon/radeon_combios.c
+++ b/drivers/gpu/drm/radeon/radeon_combios.c
@@ -450,29 +450,29 @@ struct radeon_i2c_bus_rec combios_setup_i2c_bus(int ddc_line)
 	i2c.mask_data_mask = RADEON_GPIO_EN_0;
 	i2c.a_clk_mask = RADEON_GPIO_A_1;
 	i2c.a_data_mask = RADEON_GPIO_A_0;
-	i2c.put_clk_mask = RADEON_GPIO_EN_1;
-	i2c.put_data_mask = RADEON_GPIO_EN_0;
-	i2c.get_clk_mask = RADEON_GPIO_Y_1;
-	i2c.get_data_mask = RADEON_GPIO_Y_0;
+	i2c.en_clk_mask = RADEON_GPIO_EN_1;
+	i2c.en_data_mask = RADEON_GPIO_EN_0;
+	i2c.y_clk_mask = RADEON_GPIO_Y_1;
+	i2c.y_data_mask = RADEON_GPIO_Y_0;
 	if ((ddc_line == RADEON_LCD_GPIO_MASK) ||
 	    (ddc_line == RADEON_MDGPIO_EN_REG)) {
 		i2c.mask_clk_reg = ddc_line;
 		i2c.mask_data_reg = ddc_line;
 		i2c.a_clk_reg = ddc_line;
 		i2c.a_data_reg = ddc_line;
-		i2c.put_clk_reg = ddc_line;
-		i2c.put_data_reg = ddc_line;
-		i2c.get_clk_reg = ddc_line + 4;
-		i2c.get_data_reg = ddc_line + 4;
+		i2c.en_clk_reg = ddc_line;
+		i2c.en_data_reg = ddc_line;
+		i2c.y_clk_reg = ddc_line + 4;
+		i2c.y_data_reg = ddc_line + 4;
 	} else {
 		i2c.mask_clk_reg = ddc_line;
 		i2c.mask_data_reg = ddc_line;
 		i2c.a_clk_reg = ddc_line;
 		i2c.a_data_reg = ddc_line;
-		i2c.put_clk_reg = ddc_line;
-		i2c.put_data_reg = ddc_line;
-		i2c.get_clk_reg = ddc_line;
-		i2c.get_data_reg = ddc_line;
+		i2c.en_clk_reg = ddc_line;
+		i2c.en_data_reg = ddc_line;
+		i2c.y_clk_reg = ddc_line;
+		i2c.y_data_reg = ddc_line;
 	}
 
 	if (ddc_line)
@@ -1567,18 +1567,18 @@ static bool radeon_apply_legacy_quirks(struct drm_device *dev,
 		ddc_i2c->mask_data_mask = 0x80;
 		ddc_i2c->a_clk_mask = (0x20 << 8);
 		ddc_i2c->a_data_mask = 0x80;
-		ddc_i2c->put_clk_mask = (0x20 << 8);
-		ddc_i2c->put_data_mask = 0x80;
-		ddc_i2c->get_clk_mask = (0x20 << 8);
-		ddc_i2c->get_data_mask = 0x80;
+		ddc_i2c->en_clk_mask = (0x20 << 8);
+		ddc_i2c->en_data_mask = 0x80;
+		ddc_i2c->y_clk_mask = (0x20 << 8);
+		ddc_i2c->y_data_mask = 0x80;
 		ddc_i2c->mask_clk_reg = RADEON_GPIOPAD_MASK;
 		ddc_i2c->mask_data_reg = RADEON_GPIOPAD_MASK;
 		ddc_i2c->a_clk_reg = RADEON_GPIOPAD_A;
 		ddc_i2c->a_data_reg = RADEON_GPIOPAD_A;
-		ddc_i2c->put_clk_reg = RADEON_GPIOPAD_EN;
-		ddc_i2c->put_data_reg = RADEON_GPIOPAD_EN;
-		ddc_i2c->get_clk_reg = RADEON_LCD_GPIO_Y_REG;
-		ddc_i2c->get_data_reg = RADEON_LCD_GPIO_Y_REG;
+		ddc_i2c->en_clk_reg = RADEON_GPIOPAD_EN;
+		ddc_i2c->en_data_reg = RADEON_GPIOPAD_EN;
+		ddc_i2c->y_clk_reg = RADEON_LCD_GPIO_Y_REG;
+		ddc_i2c->y_data_reg = RADEON_LCD_GPIO_Y_REG;
 	}
 
 	/* Certain IBM chipset RN50s have a BIOS reporting two VGAs,
@@ -1939,13 +1939,13 @@ bool radeon_get_legacy_connector_info_from_bios(struct drm_device *dev)
 					    RBIOS32(lcd_ddc_info + 3);
 					ddc_i2c.a_data_mask =
 					    RBIOS32(lcd_ddc_info + 7);
-					ddc_i2c.put_clk_mask =
+					ddc_i2c.en_clk_mask =
 					    RBIOS32(lcd_ddc_info + 3);
-					ddc_i2c.put_data_mask =
+					ddc_i2c.en_data_mask =
 					    RBIOS32(lcd_ddc_info + 7);
-					ddc_i2c.get_clk_mask =
+					ddc_i2c.y_clk_mask =
 					    RBIOS32(lcd_ddc_info + 3);
-					ddc_i2c.get_data_mask =
+					ddc_i2c.y_data_mask =
 					    RBIOS32(lcd_ddc_info + 7);
 					break;
 				case DDC_GPIO:
@@ -1960,13 +1960,13 @@ bool radeon_get_legacy_connector_info_from_bios(struct drm_device *dev)
 					    RBIOS32(lcd_ddc_info + 3);
 					ddc_i2c.a_data_mask =
 					    RBIOS32(lcd_ddc_info + 7);
-					ddc_i2c.put_clk_mask =
+					ddc_i2c.en_clk_mask =
 					    RBIOS32(lcd_ddc_info + 3);
-					ddc_i2c.put_data_mask =
+					ddc_i2c.en_data_mask =
 					    RBIOS32(lcd_ddc_info + 7);
-					ddc_i2c.get_clk_mask =
+					ddc_i2c.y_clk_mask =
 					    RBIOS32(lcd_ddc_info + 3);
-					ddc_i2c.get_data_mask =
+					ddc_i2c.y_data_mask =
 					    RBIOS32(lcd_ddc_info + 7);
 					break;
 				default:
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index a3def191e98..8b117e82e5e 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -270,10 +270,10 @@ static void radeon_print_display_setup(struct drm_device *dev)
 				 radeon_connector->ddc_bus->rec.mask_data_reg,
 				 radeon_connector->ddc_bus->rec.a_clk_reg,
 				 radeon_connector->ddc_bus->rec.a_data_reg,
-				 radeon_connector->ddc_bus->rec.put_clk_reg,
-				 radeon_connector->ddc_bus->rec.put_data_reg,
-				 radeon_connector->ddc_bus->rec.get_clk_reg,
-				 radeon_connector->ddc_bus->rec.get_data_reg);
+				 radeon_connector->ddc_bus->rec.en_clk_reg,
+				 radeon_connector->ddc_bus->rec.en_data_reg,
+				 radeon_connector->ddc_bus->rec.y_clk_reg,
+				 radeon_connector->ddc_bus->rec.y_data_reg);
 		DRM_INFO("  Encoders:\n");
 		list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 			radeon_encoder = to_radeon_encoder(encoder);
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index d8296acb082..e97a3912d99 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -78,16 +78,16 @@ void radeon_i2c_do_lock(struct radeon_i2c_chan *i2c, int lock_state)
 						R200_DVI_I2C_PIN_SEL(R200_SEL_DDC3)));
 		}
 	}
-	if (lock_state) {
-		temp = RREG32(rec->a_clk_reg);
-		temp &= ~(rec->a_clk_mask);
-		WREG32(rec->a_clk_reg, temp);
-
-		temp = RREG32(rec->a_data_reg);
-		temp &= ~(rec->a_data_mask);
-		WREG32(rec->a_data_reg, temp);
-	}
 
+	/* clear the output pin values */
+	temp = RREG32(rec->a_clk_reg) & ~rec->a_clk_mask;
+	WREG32(rec->a_clk_reg, temp);
+
+	temp = RREG32(rec->a_data_reg) & ~rec->a_data_mask;
+	WREG32(rec->a_data_reg, temp);
+
+
+	/* mask the gpio pins for software use */
 	temp = RREG32(rec->mask_clk_reg);
 	if (lock_state)
 		temp |= rec->mask_clk_mask;
@@ -112,8 +112,9 @@ static int get_clock(void *i2c_priv)
 	struct radeon_i2c_bus_rec *rec = &i2c->rec;
 	uint32_t val;
 
-	val = RREG32(rec->get_clk_reg);
-	val &= rec->get_clk_mask;
+	/* read the value off the pin */
+	val = RREG32(rec->y_clk_reg);
+	val &= rec->y_clk_mask;
 
 	return (val != 0);
 }
@@ -126,8 +127,10 @@ static int get_data(void *i2c_priv)
 	struct radeon_i2c_bus_rec *rec = &i2c->rec;
 	uint32_t val;
 
-	val = RREG32(rec->get_data_reg);
-	val &= rec->get_data_mask;
+	/* read the value off the pin */
+	val = RREG32(rec->y_data_reg);
+	val &= rec->y_data_mask;
+
 	return (val != 0);
 }
 
@@ -138,9 +141,10 @@ static void set_clock(void *i2c_priv, int clock)
 	struct radeon_i2c_bus_rec *rec = &i2c->rec;
 	uint32_t val;
 
-	val = RREG32(rec->put_clk_reg) & (uint32_t)~(rec->put_clk_mask);
-	val |= clock ? 0 : rec->put_clk_mask;
-	WREG32(rec->put_clk_reg, val);
+	/* set pin direction */
+	val = RREG32(rec->en_clk_reg) & ~rec->en_clk_mask;
+	val |= clock ? 0 : rec->en_clk_mask;
+	WREG32(rec->en_clk_reg, val);
 }
 
 static void set_data(void *i2c_priv, int data)
@@ -150,9 +154,10 @@ static void set_data(void *i2c_priv, int data)
 	struct radeon_i2c_bus_rec *rec = &i2c->rec;
 	uint32_t val;
 
-	val = RREG32(rec->put_data_reg) & (uint32_t)~(rec->put_data_mask);
-	val |= data ? 0 : rec->put_data_mask;
-	WREG32(rec->put_data_reg, val);
+	/* set pin direction */
+	val = RREG32(rec->en_data_reg) & ~rec->en_data_mask;
+	val |= data ? 0 : rec->en_data_mask;
+	WREG32(rec->en_data_reg, val);
 }
 
 struct radeon_i2c_chan *radeon_i2c_create(struct drm_device *dev,
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 491a1ec81a4..20847a2fc4d 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -89,24 +89,38 @@ enum radeon_tv_std {
 	TV_STD_PAL_CN,
 };
 
+/* radeon gpio-based i2c
+ * 1. "mask" reg and bits
+ *    grabs the gpio pins for software use
+ *    0=not held  1=held
+ * 2. "a" reg and bits
+ *    output pin value
+ *    0=low 1=high
+ * 3. "en" reg and bits
+ *    sets the pin direction
+ *    0=input 1=output
+ * 4. "y" reg and bits
+ *    input pin value
+ *    0=low 1=high
+ */
 struct radeon_i2c_bus_rec {
 	bool valid;
 	uint32_t mask_clk_reg;
 	uint32_t mask_data_reg;
 	uint32_t a_clk_reg;
 	uint32_t a_data_reg;
-	uint32_t put_clk_reg;
-	uint32_t put_data_reg;
-	uint32_t get_clk_reg;
-	uint32_t get_data_reg;
+	uint32_t en_clk_reg;
+	uint32_t en_data_reg;
+	uint32_t y_clk_reg;
+	uint32_t y_data_reg;
 	uint32_t mask_clk_mask;
 	uint32_t mask_data_mask;
-	uint32_t put_clk_mask;
-	uint32_t put_data_mask;
-	uint32_t get_clk_mask;
-	uint32_t get_data_mask;
 	uint32_t a_clk_mask;
 	uint32_t a_data_mask;
+	uint32_t en_clk_mask;
+	uint32_t en_data_mask;
+	uint32_t y_clk_mask;
+	uint32_t y_data_mask;
 };
 
 struct radeon_tmds_pll {