FROMLIST: drm: bridge/dw_hdmi: add dw hdmi i2c bus adapter support
authorVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Sun, 30 Aug 2015 21:34:30 +0000 (00:34 +0300)
committerHuang, Tao <huangtao@rock-chips.com>
Tue, 16 Aug 2016 06:22:40 +0000 (14:22 +0800)
The change adds support of internal HDMI I2C master controller, this
subdevice is used by default, if "ddc-i2c-bus" DT property is omitted.

The main purpose of this functionality is to support reading EDID from
an HDMI monitor on boards, which don't have an I2C bus connected to
DDC pins.

The current implementation does not support "I2C Master Interface
Extended Read Mode" to read data addressed by non-zero segment
pointer, this means that if EDID has more than 1 extension blocks,
EDID reading operation won't succeed, in my practice all tested HDMI
monitors have at maximum one extension block.
(am from https://patchwork.kernel.org/patch/7098101)

Change-Id: Ic3abe878a02f89bda15f39676164803b467c62a1
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/292012
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
drivers/gpu/drm/bridge/dw-hdmi.c
drivers/gpu/drm/bridge/dw-hdmi.h

index c5d7b27fd90d6992fa92dbdb765aeacfcff9a7bb..a01d357aca0181c081895f1f5e5f1b877067aeeb 100644 (file)
@@ -1,5 +1,9 @@
 /*
+ * DesignWare High-Definition Multimedia Interface (HDMI) driver
+ *
+ * Copyright (C) 2013-2015 Mentor Graphics Inc.
  * Copyright (C) 2011-2013 Freescale Semiconductor, Inc.
+ * Copyright (C) 2010, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -8,7 +12,6 @@
  *
  * Designware High-Definition Multimedia Interface (HDMI) driver
  *
- * Copyright (C) 2010, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
  */
 #include <linux/module.h>
 #include <linux/irq.h>
@@ -157,6 +160,17 @@ struct hdmi_data_info {
        struct hdmi_vmode video_mode;
 };
 
+struct dw_hdmi_i2c {
+       struct i2c_adapter      adap;
+
+       struct mutex            lock;
+       struct completion       cmp;
+       u8                      stat;
+
+       u8                      slave_reg;
+       bool                    is_regaddr;
+};
+
 struct dw_hdmi {
        struct drm_connector connector;
        struct drm_encoder *encoder;
@@ -167,6 +181,7 @@ struct dw_hdmi {
        struct device *dev;
        struct clk *isfr_clk;
        struct clk *iahb_clk;
+       struct dw_hdmi_i2c *i2c;
 
        struct hdmi_data_info hdmi_data;
        const struct dw_hdmi_plat_data *plat_data;
@@ -254,6 +269,200 @@ static void hdmi_mask_writeb(struct dw_hdmi *hdmi, u8 data, unsigned int reg,
        hdmi_modb(hdmi, data << shift, mask, reg);
 }
 
+static void dw_hdmi_i2c_init(struct dw_hdmi *hdmi)
+{
+       /* Set Fast Mode speed */
+       hdmi_writeb(hdmi, 0x0b, HDMI_I2CM_DIV);
+
+       /* Software reset */
+       hdmi_writeb(hdmi, 0x00, HDMI_I2CM_SOFTRSTZ);
+
+       /* Set done, not acknowledged and arbitration interrupt polarities */
+       hdmi_writeb(hdmi, HDMI_I2CM_INT_DONE_POL, HDMI_I2CM_INT);
+       hdmi_writeb(hdmi, HDMI_I2CM_CTLINT_NAC_POL | HDMI_I2CM_CTLINT_ARB_POL,
+                   HDMI_I2CM_CTLINT);
+
+       /* Clear DONE and ERROR interrupts */
+       hdmi_writeb(hdmi, HDMI_IH_I2CM_STAT0_ERROR | HDMI_IH_I2CM_STAT0_DONE,
+                   HDMI_IH_I2CM_STAT0);
+
+       /* Mute DONE and ERROR interrupts */
+       hdmi_writeb(hdmi, HDMI_IH_I2CM_STAT0_ERROR | HDMI_IH_I2CM_STAT0_DONE,
+                   HDMI_IH_MUTE_I2CM_STAT0);
+}
+
+static int dw_hdmi_i2c_read(struct dw_hdmi *hdmi,
+                           unsigned char *buf, unsigned int length)
+{
+       struct dw_hdmi_i2c *i2c = hdmi->i2c;
+       int stat;
+
+       if (!i2c->is_regaddr) {
+               dev_dbg(hdmi->dev, "set read register address to 0\n");
+               i2c->slave_reg = 0x00;
+               i2c->is_regaddr = true;
+       }
+
+       while (length--) {
+               reinit_completion(&i2c->cmp);
+
+               hdmi_writeb(hdmi, i2c->slave_reg++, HDMI_I2CM_ADDRESS);
+               hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ,
+                           HDMI_I2CM_OPERATION);
+
+               stat = wait_for_completion_timeout(&i2c->cmp, HZ / 10);
+               if (!stat)
+                       return -EAGAIN;
+
+               /* Check for error condition on the bus */
+               if (i2c->stat & HDMI_IH_I2CM_STAT0_ERROR)
+                       return -EIO;
+
+               *buf++ = hdmi_readb(hdmi, HDMI_I2CM_DATAI);
+       }
+
+       return 0;
+}
+
+static int dw_hdmi_i2c_write(struct dw_hdmi *hdmi,
+                            unsigned char *buf, unsigned int length)
+{
+       struct dw_hdmi_i2c *i2c = hdmi->i2c;
+       int stat;
+
+       if (!i2c->is_regaddr) {
+               /* Use the first write byte as register address */
+               i2c->slave_reg = buf[0];
+               length--;
+               buf++;
+               i2c->is_regaddr = true;
+       }
+
+       while (length--) {
+               reinit_completion(&i2c->cmp);
+
+               hdmi_writeb(hdmi, *buf++, HDMI_I2CM_DATAO);
+               hdmi_writeb(hdmi, i2c->slave_reg++, HDMI_I2CM_ADDRESS);
+               hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_WRITE,
+                           HDMI_I2CM_OPERATION);
+
+       stat = wait_for_completion_timeout(&i2c->cmp, HZ / 10);
+               if (!stat)
+                       return -EAGAIN;
+
+               /* Check for error condition on the bus */
+               if (i2c->stat & HDMI_IH_I2CM_STAT0_ERROR)
+                       return -EIO;
+       }
+
+       return 0;
+}
+
+static int dw_hdmi_i2c_xfer(struct i2c_adapter *adap,
+                           struct i2c_msg *msgs, int num)
+{
+       struct dw_hdmi *hdmi = i2c_get_adapdata(adap);
+       struct dw_hdmi_i2c *i2c = hdmi->i2c;
+       u8 addr = msgs[0].addr;
+       int i, ret = 0;
+
+       dev_dbg(hdmi->dev, "xfer: num: %d, addr: %#x\n", num, addr);
+
+       for (i = 0; i < num; i++) {
+               if (msgs[i].addr != addr) {
+                       dev_warn(hdmi->dev,
+                                "unsupported transfer, changed slave address\n");
+                       return -EOPNOTSUPP;
+               }
+
+               if (msgs[i].len == 0) {
+                       dev_dbg(hdmi->dev,
+                               "unsupported transfer %d/%d, no data\n",
+                               i + 1, num);
+                       return -EOPNOTSUPP;
+               }
+       }
+
+       mutex_lock(&i2c->lock);
+
+       hdmi_writeb(hdmi, 0x00, HDMI_IH_MUTE_I2CM_STAT0);
+
+       /* Set slave device address taken from the first I2C message */
+       hdmi_writeb(hdmi, addr, HDMI_I2CM_SLAVE);
+
+       /* Set slave device register address on transfer */
+       i2c->is_regaddr = false;
+
+       for (i = 0; i < num; i++) {
+               dev_dbg(hdmi->dev, "xfer: num: %d/%d, len: %d, flags: %#x\n",
+                       i + 1, num, msgs[i].len, msgs[i].flags);
+
+               if (msgs[i].flags & I2C_M_RD)
+                       ret = dw_hdmi_i2c_read(hdmi, msgs[i].buf, msgs[i].len);
+               else
+                       ret = dw_hdmi_i2c_write(hdmi, msgs[i].buf, msgs[i].len);
+
+               if (ret < 0)
+                       break;
+       }
+
+       if (!ret)
+               ret = num;
+
+       /* Mute DONE and ERROR interrupts */
+       hdmi_writeb(hdmi, HDMI_IH_I2CM_STAT0_ERROR | HDMI_IH_I2CM_STAT0_DONE,
+                   HDMI_IH_MUTE_I2CM_STAT0);
+
+       mutex_unlock(&i2c->lock);
+
+       return ret;
+}
+
+static u32 dw_hdmi_i2c_func(struct i2c_adapter *adapter)
+{
+       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm dw_hdmi_algorithm = {
+       .master_xfer    = dw_hdmi_i2c_xfer,
+       .functionality  = dw_hdmi_i2c_func,
+};
+
+static struct i2c_adapter *dw_hdmi_i2c_adapter(struct dw_hdmi *hdmi)
+{
+       struct i2c_adapter *adap;
+       struct dw_hdmi_i2c *i2c;
+       int ret;
+
+       i2c = devm_kzalloc(hdmi->dev, sizeof(*i2c), GFP_KERNEL);
+       if (!i2c)
+               return ERR_PTR(-ENOMEM);
+
+       mutex_init(&i2c->lock);
+       init_completion(&i2c->cmp);
+
+       adap = &i2c->adap;
+       adap->class = I2C_CLASS_DDC;
+       adap->owner = THIS_MODULE;
+       adap->dev.parent = hdmi->dev;
+       adap->algo = &dw_hdmi_algorithm;
+       strlcpy(adap->name, "DesignWare HDMI", sizeof(adap->name));
+       i2c_set_adapdata(adap, hdmi);
+
+       ret = i2c_add_adapter(adap);
+       if (ret) {
+               dev_warn(hdmi->dev, "cannot add %s I2C adapter\n", adap->name);
+               devm_kfree(hdmi->dev, i2c);
+               return ERR_PTR(ret);
+       }
+
+       hdmi->i2c = i2c;
+
+       dev_info(hdmi->dev, "registered %s I2C bus driver\n", adap->name);
+
+       return adap;
+}
+
 static void hdmi_set_cts_n(struct dw_hdmi *hdmi, unsigned int cts,
                           unsigned int n)
 {
@@ -1654,16 +1863,40 @@ static const struct drm_bridge_funcs dw_hdmi_bridge_funcs = {
        .mode_set = dw_hdmi_bridge_mode_set,
 };
 
+static irqreturn_t dw_hdmi_i2c_irq(struct dw_hdmi *hdmi)
+{
+       struct dw_hdmi_i2c *i2c = hdmi->i2c;
+       unsigned int stat;
+
+       stat = hdmi_readb(hdmi, HDMI_IH_I2CM_STAT0);
+       if (!stat)
+               return IRQ_NONE;
+
+       hdmi_writeb(hdmi, stat, HDMI_IH_I2CM_STAT0);
+
+       i2c->stat = stat;
+
+       complete(&i2c->cmp);
+
+       return IRQ_HANDLED;
+}
+
 static irqreturn_t dw_hdmi_hardirq(int irq, void *dev_id)
 {
        struct dw_hdmi *hdmi = dev_id;
        u8 intr_stat;
+       irqreturn_t ret = IRQ_NONE;
+
+       if (hdmi->i2c)
+               ret = dw_hdmi_i2c_irq(hdmi);
 
        intr_stat = hdmi_readb(hdmi, HDMI_IH_PHY_STAT0);
-       if (intr_stat)
+       if (intr_stat) {
                hdmi_writeb(hdmi, ~0, HDMI_IH_MUTE_PHY_STAT0);
+               return IRQ_WAKE_THREAD;
+       }
 
-       return intr_stat ? IRQ_WAKE_THREAD : IRQ_NONE;
+       return ret;
 }
 
 static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
@@ -1841,6 +2074,13 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
                dev_dbg(hdmi->dev, "no ddc property found\n");
        }
 
+       /* If DDC bus is not specified, try to register HDMI I2C bus */
+       if (!hdmi->ddc) {
+               hdmi->ddc = dw_hdmi_i2c_adapter(hdmi);
+               if (IS_ERR(hdmi->ddc))
+                       hdmi->ddc = NULL;
+       }
+
        hdmi->regs = devm_ioremap_resource(dev, iores);
        if (IS_ERR(hdmi->regs))
                return PTR_ERR(hdmi->regs);
@@ -1915,6 +2155,10 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
        hdmi_writeb(hdmi, ~(HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE),
                    HDMI_IH_MUTE_PHY_STAT0);
 
+       /* Unmute I2CM interrupts and reset HDMI DDC I2C master controller */
+       if (hdmi->i2c)
+               dw_hdmi_i2c_init(hdmi);
+
        memset(&pdevinfo, 0, sizeof(pdevinfo));
        pdevinfo.parent = dev;
        pdevinfo.id = PLATFORM_DEVID_AUTO;
@@ -1955,6 +2199,9 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
        return 0;
 
 err_iahb:
+       if (hdmi->i2c)
+               i2c_del_adapter(&hdmi->i2c->adap);
+
        clk_disable_unprepare(hdmi->iahb_clk);
 err_isfr:
        clk_disable_unprepare(hdmi->isfr_clk);
@@ -1978,13 +2225,18 @@ void dw_hdmi_unbind(struct device *dev, struct device *master, void *data)
 
        clk_disable_unprepare(hdmi->iahb_clk);
        clk_disable_unprepare(hdmi->isfr_clk);
-       i2c_put_adapter(hdmi->ddc);
+
+       if (hdmi->i2c)
+               i2c_del_adapter(&hdmi->i2c->adap);
+       else
+               i2c_put_adapter(hdmi->ddc);
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_unbind);
 
 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com>");
 MODULE_AUTHOR("Yakir Yang <ykk@rock-chips.com>");
+MODULE_AUTHOR("Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>");
 MODULE_DESCRIPTION("DW HDMI transmitter driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:dw-hdmi");
index cad1dfbc950f38fc8488f09dd4a088a66fb9c76d..c88e59b6376fde6790382c74d2a7e40cdaf0fdab 100644 (file)
@@ -570,6 +570,10 @@ enum {
        HDMI_IH_PHY_STAT0_TX_PHY_LOCK = 0x2,
        HDMI_IH_PHY_STAT0_HPD = 0x1,
 
+/* IH_I2CM_STAT0 and IH_MUTE_I2CM_STAT0 field values */
+       HDMI_IH_I2CM_STAT0_DONE = 0x2,
+       HDMI_IH_I2CM_STAT0_ERROR = 0x1,
+
 /* IH_MUTE_I2CMPHY_STAT0 field values */
        HDMI_IH_MUTE_I2CMPHY_STAT0_I2CMPHYDONE = 0x2,
        HDMI_IH_MUTE_I2CMPHY_STAT0_I2CMPHYERROR = 0x1,
@@ -1057,6 +1061,21 @@ enum {
        HDMI_A_VIDPOLCFG_HSYNCPOL_MASK = 0x2,
        HDMI_A_VIDPOLCFG_HSYNCPOL_ACTIVE_HIGH = 0x2,
        HDMI_A_VIDPOLCFG_HSYNCPOL_ACTIVE_LOW = 0x0,
+
+/* I2CM_OPERATION field values */
+       HDMI_I2CM_OPERATION_WRITE = 0x10,
+       HDMI_I2CM_OPERATION_READ_EXT = 0x2,
+       HDMI_I2CM_OPERATION_READ = 0x1,
+
+/* I2CM_INT field values */
+       HDMI_I2CM_INT_DONE_POL = 0x8,
+       HDMI_I2CM_INT_DONE_MASK = 0x4,
+
+/* I2CM_CTLINT field values */
+       HDMI_I2CM_CTLINT_NAC_POL = 0x80,
+       HDMI_I2CM_CTLINT_NAC_MASK = 0x40,
+       HDMI_I2CM_CTLINT_ARB_POL = 0x8,
+       HDMI_I2CM_CTLINT_ARB_MASK = 0x4,
 };
 
 #endif /* __DW_HDMI_H__ */