drm/radeon/kms: take the pm mutex when using hw i2c

we need a constant sclk for i2c prescale.  Also,
get the current sclk when calculating prescale rather
than using the default sclk.

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

1 files changed, 17 insertions, 9 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index b47a5615fe6a..272c45db5cec 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -192,12 +192,16 @@ static int r100_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
         struct radeon_i2c_bus_rec *rec = &i2c->rec;
         struct i2c_msg *p;
         int i, j, k, ret = num;
-        /* XXX: use get_engine_clock() to get the current sclk */
-        u32 prescale = (((rdev->clock.default_sclk * 10)/(4 * 128 * 100) + 1) << 8) + 128;
+        u32 sclk, prescale;
         u32 i2c_cntl_0, i2c_cntl_1, i2c_data;
         u32 tmp, reg;
 
         mutex_lock(&rdev->dc_hw_i2c_mutex);
+        /* take the pm lock since we need a constant sclk */
+        mutex_lock(&rdev->pm.mutex);
+
+        sclk = radeon_get_engine_clock(rdev);
+        prescale = (((sclk * 10)/(4 * 128 * 100) + 1) << 8) + 128;
 
         reg = ((prescale << RADEON_I2C_PRESCALE_SHIFT) |
                RADEON_I2C_START |
@@ -424,6 +428,7 @@ done:
                 WREG32(RADEON_BIOS_6_SCRATCH, tmp);
         }
 
+        mutex_unlock(&rdev->pm.mutex);
         mutex_unlock(&rdev->dc_hw_i2c_mutex);
 
         return ret;
@@ -441,12 +446,19 @@ static int r500_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
         struct i2c_msg *p;
         int i2c_clock = 50;
         int i, j, remaining, current_count, buffer_offset, ret = num;
-        /* XXX: use get_engine_clock() to get the current sclk */
-        u32 prescale;
+        u32 sclk, prescale;
         u32 tmp, reg;
         u32 saved1, saved2;
 
         mutex_lock(&rdev->dc_hw_i2c_mutex);
+        /* take the pm lock since we need a constant sclk */
+        mutex_lock(&rdev->pm.mutex);
+
+        sclk = radeon_get_engine_clock(rdev);
+        if (rdev->family == CHIP_R520)
+                prescale = (127 << 8) + ((sclk * 10) / (4 * 127 * i2c_clock));
+        else
+                prescale = (((sclk * 10)/(4 * 128 * 100) + 1) << 8) + 128;
 
         /* clear gpio mask bits */
         tmp = RREG32(rec->mask_clk_reg);
@@ -500,11 +512,6 @@ static int r500_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
                 goto done;
         }
 
-        if (rdev->family == CHIP_R520)
-                prescale = (127 << 8) + ((rdev->clock.default_sclk * 10) / (4 * 127 * i2c_clock));
-        else
-                prescale = (((rdev->clock.default_sclk * 10)/(4 * 128 * 100) + 1) << 8) + 128;
-
         reg = AVIVO_DC_I2C_START | AVIVO_DC_I2C_STOP | AVIVO_DC_I2C_EN;
         switch (rec->mask_clk_reg) {
         case AVIVO_DC_GPIO_DDC1_MASK:
@@ -662,6 +669,7 @@ done:
         tmp &= ~ATOM_S6_HW_I2C_BUSY_STATE;
         WREG32(RADEON_BIOS_6_SCRATCH, tmp);
 
+        mutex_unlock(&rdev->pm.mutex);
         mutex_unlock(&rdev->dc_hw_i2c_mutex);
 
         return ret;