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drm/i915: Program GMBUS Frequency based on the CDCLK for VLV.

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CDCLK is used to generate the gmbus clock.  This is normally done by
BIOS. Program the value if the BIOS-less system doesn't do it.

v2: Move this to intel_i2c_reset to allow reprogram the gmbus frequency
during resume. (Daniel)

v3: Change GMBUS_FREQ to GMBUSFREQ_VLV, and use VLV_DISPLAY_BASE.
(Ville).
	Remove cdclk_ratio[] table, and calculate the cdclk ratio instead.
(Ville).
 	Change the shift then mask for reg read, to mask first, then shift.
(Ville).
	Remove the gmbus frequency calculation = cdclk/1.01.  Based on BIOS
programming, gmbus frequency = cdclk frequency. (Ville)
	Add get_disp_clk_div, which can use to get cdclk/czclk divide.

v4: Fix the mmio_offset base for CZCLK_CDCLK_FREQ_RATIO, gmbus_freq
calculation, and duplicate check for gmbus_freq. (Ville)

In VLV, the spec is wrong about 4Mhz reference frequency for GMBUS. It
should be 1Mhz.

Signed-off-by: Chon Ming Lee <chon.ming.lee@intel.com>
[danvet: Add the comment Ville suggested. Also appease checkpatch a
bit.]
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Chon Ming Lee 2013-09-27 15:31:00 +08:00 committed by Daniel Vetter
parent afc85b9d9e
commit 24eb2d599b
2 changed files with 72 additions and 0 deletions
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8
drivers/gpu/drm/i915/i915_reg.h
View file

@ -382,6 +382,8 @@
#define FB_FMAX_VMIN_FREQ_LO_MASK 0xf8000000
/* vlv2 north clock has */
#define CCK_FUSE_REG 0x8
#define CCK_FUSE_HPLL_FREQ_MASK 0x3
#define CCK_REG_DSI_PLL_FUSE 0x44
#define CCK_REG_DSI_PLL_CONTROL 0x48
#define DSI_PLL_VCO_EN (1 << 31)
@ -1429,6 +1431,12 @@
#define MI_ARB_VLV (VLV_DISPLAY_BASE + 0x6504)
#define CZCLK_CDCLK_FREQ_RATIO (VLV_DISPLAY_BASE + 0x6508)
#define CDCLK_FREQ_SHIFT 4
#define CDCLK_FREQ_MASK (0x1f << CDCLK_FREQ_SHIFT)
#define CZCLK_FREQ_MASK 0xf
#define GMBUSFREQ_VLV (VLV_DISPLAY_BASE + 0x6510)
/*
* Palette regs
*/

64
drivers/gpu/drm/i915/intel_i2c.c
View file

@ -34,6 +34,11 @@
#include <drm/i915_drm.h>
#include "i915_drv.h"
enum disp_clk {
CDCLK,
CZCLK
};
struct gmbus_port {
const char *name;
int reg;
@ -58,10 +63,69 @@ to_intel_gmbus(struct i2c_adapter *i2c)
return container_of(i2c, struct intel_gmbus, adapter);
}
static int get_disp_clk_div(struct drm_i915_private *dev_priv,
enum disp_clk clk)
{
u32 reg_val;
int clk_ratio;
reg_val = I915_READ(CZCLK_CDCLK_FREQ_RATIO);
if (clk == CDCLK)
clk_ratio =
((reg_val & CDCLK_FREQ_MASK) >> CDCLK_FREQ_SHIFT) + 1;
else
clk_ratio = (reg_val & CZCLK_FREQ_MASK) + 1;
return clk_ratio;
}
static void gmbus_set_freq(struct drm_i915_private *dev_priv)
{
int vco_freq[] = { 800, 1600, 2000, 2400 };
int gmbus_freq = 0, cdclk_div, hpll_freq;
BUG_ON(!IS_VALLEYVIEW(dev_priv->dev));
/* Skip setting the gmbus freq if BIOS has already programmed it */
if (I915_READ(GMBUSFREQ_VLV) != 0xA0)
return;
/* Obtain SKU information */
mutex_lock(&dev_priv->dpio_lock);
hpll_freq =
vlv_cck_read(dev_priv, CCK_FUSE_REG) & CCK_FUSE_HPLL_FREQ_MASK;
mutex_unlock(&dev_priv->dpio_lock);
/* Get the CDCLK divide ratio */
cdclk_div = get_disp_clk_div(dev_priv, CDCLK);
/*
* Program the gmbus_freq based on the cdclk frequency.
* BSpec erroneously claims we should aim for 4MHz, but
* in fact 1MHz is the correct frequency.
*/
if (cdclk_div)
gmbus_freq = (vco_freq[hpll_freq] << 1) / cdclk_div;
if (WARN_ON(gmbus_freq == 0))
return;
I915_WRITE(GMBUSFREQ_VLV, gmbus_freq);
}
void
intel_i2c_reset(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
/*
* In BIOS-less system, program the correct gmbus frequency
* before reading edid.
*/
if (IS_VALLEYVIEW(dev))
gmbus_set_freq(dev_priv);
I915_WRITE(dev_priv->gpio_mmio_base + GMBUS0, 0);
I915_WRITE(dev_priv->gpio_mmio_base + GMBUS4, 0);
}