Re: [PATCH 04/12] I2C re-init for every cmd

["shekhar, chandra" <x0044955@ti.com>]

Hi,

This patch looks ok.
i would have preferred runtime check for 34xx. It will be a bit overhead for 
previous platforms.
but will be good for  multi-omap support.

----- Original Message ----- 
From: ""Högander" Jouni" <jouni.hogander@nokia.com>
To: "ext chandra shekhar" <x0044955@ti.com>
Cc: <linux-omap@vger.kernel.org>
Sent: Friday, September 12, 2008 1:18 PM
Subject: Re: [PATCH 04/12] I2C re-init for every cmd


"ext chandra shekhar" <x0044955@ti.com> writes:

> agreed..but i guess it will not compile for 2430 and prev. platforms.
> omap3_i2c_save_context and restore definition is under macro
> while call is not. let me know if i am missing something.
>
> also is SYSC register restore needed??

Here is the second version. Does it look any better to you?

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 3778735..0a11621 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -147,6 +147,12 @@ struct omap_i2c_dev {
        unsigned                b_hw:1;         /* bad h/w fixes */
        unsigned                idle:1;
        u16                     iestate;        /* Saved interrupt register */
+#ifdef CONFIG_ARCH_OMAP34XX
+       u16                     pscstate;
+       u16                     scllstate;
+       u16                     sclhstate;
+       u16                     bufstate;
+#endif
 };

 static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
@@ -209,16 +215,21 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev)
        if (dev->iclk != NULL)
                clk_enable(dev->iclk);
        clk_enable(dev->fclk);
+
+#ifdef CONFIG_ARCH_OMAP34XX
+       omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);
+       omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
+       omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
+       omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, dev->bufstate);
+#endif
        dev->idle = 0;
-       if (dev->iestate)
-               omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
+       omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
 }

 static void omap_i2c_idle(struct omap_i2c_dev *dev)
 {
        u16 iv;

-       dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
        omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
        if (dev->rev1)
                iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
@@ -238,7 +249,7 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev)

 static int omap_i2c_init(struct omap_i2c_dev *dev)
 {
-       u16 psc = 0, scll = 0, sclh = 0;
+       u16 psc = 0, scll = 0, sclh = 0, buf = 0;
        u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
        unsigned long fclk_rate = 12000000;
        unsigned long timeout;
@@ -327,23 +338,30 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
        omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
        omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);

-       if (dev->fifo_size)
-               /* Note: setup required fifo size - 1 */
-               omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG,
-                                       (dev->fifo_size - 1) << 8 | /* RTRSH */
-                                       OMAP_I2C_BUF_RXFIF_CLR |
-                                       (dev->fifo_size - 1) | /* XTRSH */
-                                       OMAP_I2C_BUF_TXFIF_CLR);
+       if (dev->fifo_size) {
+               /* Note: setup required fifo size - 1. RTRSH and XTRSH */
+               buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR |
+                       (dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR;
+               omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
+       }

        /* Take the I2C module out of reset: */
        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);

        /* Enable interrupts */
-       omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,
-                       (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
+       dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
                        OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
                        OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
-                               (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0));
+                                           (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) 
: 0);
+       omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
+
+#ifdef CONFIG_ARCH_OMAP34XX
+       dev->pscstate = psc;
+       dev->scllstate = scll;
+       dev->sclhstate = sclh;
+       dev->bufstate = buf;
+#endif
+
        return 0;
 }

@@ -496,8 +514,6 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg 
msgs[], int num)

        omap_i2c_unidle(dev);

-       omap_i2c_init(dev);
-
        if ((r = omap_i2c_wait_for_bb(dev)) < 0)
                goto out;

-- 
Jouni Högander


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