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Subject[PATCH V4 5/6] dw-hdmi: add support for multi byte register width access
Date
On rockchip rk3288, only word(32-bit) accesses are
permitted for hdmi registers. Byte width access (writeb,
readb) generates an imprecise external abort.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
---
drivers/gpu/drm/bridge/dw_hdmi.c | 49 +++++++++++++++++++++++++++++++++++++---
1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index df76a8c..9867642 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -126,19 +126,42 @@ struct dw_hdmi {

unsigned int sample_rate;
int ratio;
+ void (*write)(u8 val, void __iomem *addr);
+ u8 (*read)(void __iomem *addr);
+ int reg_shift;
};

+static void dw_hdmi_writel(u8 val, void __iomem *addr)
+{
+ writel(val, addr);
+}
+
+static u8 dw_hdmi_readl(void __iomem *addr)
+{
+ return readl(addr);
+}
+
+static void dw_hdmi_writeb(u8 val, void __iomem *addr)
+{
+ writeb(val, addr);
+}
+
+static u8 dw_hdmi_readb(void __iomem *addr)
+{
+ return readb(addr);
+}
+
static inline void hdmi_writeb(struct dw_hdmi *hdmi, u8 val, int offset)
{
- writeb(val, hdmi->regs + offset);
+ hdmi->write(val, hdmi->regs + (offset << hdmi->reg_shift));
}

static inline u8 hdmi_readb(struct dw_hdmi *hdmi, int offset)
{
- return readb(hdmi->regs + offset);
+ return hdmi->read(hdmi->regs + (offset << hdmi->reg_shift));
}

-static void hdmi_modb(struct dw_hdmi *hdmi, u8 data, u8 mask, unsigned reg)
+static void hdmi_modb(struct dw_hdmi *hdmi, u32 data, u32 mask, unsigned reg)
{
u8 val = hdmi_readb(hdmi, reg) & ~mask;

@@ -1499,6 +1522,26 @@ static int dw_hdmi_bind(struct device *dev, struct device *master, void *data)
struct device_node *ddc_node;
struct resource *iores;
int ret, irq;
+ u32 val;
+
+ if (!of_property_read_u32(np, "reg-io-width", &val)) {
+ switch (val) {
+ case 4:
+ hdmi->write = dw_hdmi_writel;
+ hdmi->read = dw_hdmi_readl;
+ hdmi->reg_shift = 2;
+ break;
+ default:
+ hdmi->write = dw_hdmi_writeb;
+ hdmi->read = dw_hdmi_readb;
+ hdmi->reg_shift = 0;
+ break;
+ }
+ } else {
+ hdmi->write = dw_hdmi_writeb;
+ hdmi->read = dw_hdmi_readb;
+ hdmi->reg_shift = 0;
+ }

ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
if (ddc_node) {
--
1.9.1


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