i2c-au1550: Fix PM support

Fix driver power management:
- suspend the PSC while driver is idle.
- move PSC init/deinit to separate functions, as PSC must be
  initialized/shutdown on resume/suspend.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 75 insertions, 55 deletions

diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c
index cae9dc89d88c..66a04c2c660f 100644
--- a/drivers/i2c/busses/i2c-au1550.c
+++ b/drivers/i2c/busses/i2c-au1550.c
@@ -269,9 +269,13 @@ static int
 au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
 {
         struct i2c_au1550_data *adap = i2c_adap->algo_data;
+        volatile psc_smb_t *sp = (volatile psc_smb_t *)adap->psc_base;
         struct i2c_msg *p;
         int i, err = 0;
 
+        sp->psc_ctrl = PSC_CTRL_ENABLE;
+        au_sync();
+
         for (i = 0; !err && i < num; i++) {
                 p = &msgs[i];
                 err = do_address(adap, p->addr, p->flags & I2C_M_RD,
@@ -288,6 +292,10 @@ au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
         */
         if (err == 0)
                 err = num;
+
+        sp->psc_ctrl = PSC_CTRL_SUSPEND;
+        au_sync();
+
         return err;
 }
 
@@ -302,6 +310,61 @@ static const struct i2c_algorithm au1550_algo = {
         .functionality  = au1550_func,
 };
 
+static void i2c_au1550_setup(struct i2c_au1550_data *priv)
+{
+        volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
+        u32 stat;
+
+        sp->psc_ctrl = PSC_CTRL_DISABLE;
+        au_sync();
+        sp->psc_sel = PSC_SEL_PS_SMBUSMODE;
+        sp->psc_smbcfg = 0;
+        au_sync();
+        sp->psc_ctrl = PSC_CTRL_ENABLE;
+        au_sync();
+        do {
+                stat = sp->psc_smbstat;
+                au_sync();
+        } while ((stat & PSC_SMBSTAT_SR) == 0);
+
+        sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 |
+                                PSC_SMBCFG_DD_DISABLE);
+
+        /* Divide by 8 to get a 6.25 MHz clock.  The later protocol
+         * timings are based on this clock.
+         */
+        sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
+        sp->psc_smbmsk = PSC_SMBMSK_ALLMASK;
+        au_sync();
+
+        /* Set the protocol timer values.  See Table 71 in the
+         * Au1550 Data Book for standard timing values.
+         */
+        sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
+                PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
+                PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
+                PSC_SMBTMR_SET_CH(15);
+        au_sync();
+
+        sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE;
+        do {
+                stat = sp->psc_smbstat;
+                au_sync();
+        } while ((stat & PSC_SMBSTAT_SR) == 0);
+
+        sp->psc_ctrl = PSC_CTRL_SUSPEND;
+        au_sync();
+}
+
+static void i2c_au1550_disable(struct i2c_au1550_data *priv)
+{
+        volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
+
+        sp->psc_smbcfg = 0;
+        sp->psc_ctrl = PSC_CTRL_DISABLE;
+        au_sync();
+}
+
 /*
  * registering functions to load algorithms at runtime
  * Prior to calling us, the 50MHz clock frequency and routing
@@ -311,9 +374,7 @@ static int __devinit
 i2c_au1550_probe(struct platform_device *pdev)
 {
         struct i2c_au1550_data *priv;
-        volatile psc_smb_t *sp;
         struct resource *r;
-        u32 stat;
         int ret;
 
         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -348,43 +409,7 @@ i2c_au1550_probe(struct platform_device *pdev)
 
         /* Now, set up the PSC for SMBus PIO mode.
         */
-        sp = (volatile psc_smb_t *)priv->psc_base;
-        sp->psc_ctrl = PSC_CTRL_DISABLE;
-        au_sync();
-        sp->psc_sel = PSC_SEL_PS_SMBUSMODE;
-        sp->psc_smbcfg = 0;
-        au_sync();
-        sp->psc_ctrl = PSC_CTRL_ENABLE;
-        au_sync();
-        do {
-                stat = sp->psc_smbstat;
-                au_sync();
-        } while ((stat & PSC_SMBSTAT_SR) == 0);
-
-        sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 |
-                                PSC_SMBCFG_DD_DISABLE);
-
-        /* Divide by 8 to get a 6.25 MHz clock.  The later protocol
-         * timings are based on this clock.
-         */
-        sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
-        sp->psc_smbmsk = PSC_SMBMSK_ALLMASK;
-        au_sync();
-
-        /* Set the protocol timer values.  See Table 71 in the
-         * Au1550 Data Book for standard timing values.
-         */
-        sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
-                PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
-                PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
-                PSC_SMBTMR_SET_CH(15);
-        au_sync();
-
-        sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE;
-        do {
-                stat = sp->psc_smbstat;
-                au_sync();
-        } while ((stat & PSC_SMBSTAT_DR) == 0);
+        i2c_au1550_setup(priv);
 
         ret = i2c_add_numbered_adapter(&priv->adap);
         if (ret == 0) {
@@ -392,10 +417,7 @@ i2c_au1550_probe(struct platform_device *pdev)
                 return 0;
         }
 
-        /* disable the PSC */
-        sp->psc_smbcfg = 0;
-        sp->psc_ctrl = PSC_CTRL_DISABLE;
-        au_sync();
+        i2c_au1550_disable(priv);
 
         release_resource(priv->ioarea);
         kfree(priv->ioarea);
@@ -409,27 +431,24 @@ static int __devexit
 i2c_au1550_remove(struct platform_device *pdev)
 {
         struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
-        volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
 
         platform_set_drvdata(pdev, NULL);
         i2c_del_adapter(&priv->adap);
-        sp->psc_smbcfg = 0;
-        sp->psc_ctrl = PSC_CTRL_DISABLE;
-        au_sync();
+        i2c_au1550_disable(priv);
         release_resource(priv->ioarea);
         kfree(priv->ioarea);
         kfree(priv);
         return 0;
 }
 
+#ifdef CONFIG_PM
 static int
 i2c_au1550_suspend(struct platform_device *pdev, pm_message_t state)
 {
         struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
-        volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
 
-        sp->psc_ctrl = PSC_CTRL_SUSPEND;
-        au_sync();
+        i2c_au1550_disable(priv);
+
         return 0;
 }
 
@@ -437,14 +456,15 @@ static int
 i2c_au1550_resume(struct platform_device *pdev)
 {
         struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
-        volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
 
-        sp->psc_ctrl = PSC_CTRL_ENABLE;
-        au_sync();
-        while (!(sp->psc_smbstat & PSC_SMBSTAT_SR))
-                au_sync();
+        i2c_au1550_setup(priv);
+
         return 0;
 }
+#else
+#define i2c_au1550_suspend      NULL
+#define i2c_au1550_resume       NULL
+#endif
 
 static struct platform_driver au1xpsc_smbus_driver = {
         .driver = {