i2c: omap: Fix the revision register read

The revision register on OMAP4 is a 16-bit lo and a 16-bit
hi. Currently the driver reads only the lower 8-bits.
Fix the same by preventing the truncating of the rev register
for OMAP4.

Also use the scheme bit ie bit-14 of the hi register to know if it
is OMAP_I2C_IP_VERSION_2.

On platforms previous to OMAP4 the offset 0x04 is IE register whose
bit-14 reset value is 0, the code uses the same to its advantage.

Also since the omap_i2c_read_reg uses reg_map_ip_* a raw_readw is done
to fetch the revision register.

The dev->regs is populated after reading the rev_hi. A NULL check
has been added in the resume handler to prevent the access before
the setting of the regs.

Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

1 files changed, 48 insertions, 13 deletions

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 16afb289cca7..bf0569eefeb8 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -49,9 +49,10 @@
 #define OMAP_I2C_OMAP1_REV_2            0x20
 
 /* I2C controller revisions present on specific hardware */
-#define OMAP_I2C_REV_ON_2430            0x36
-#define OMAP_I2C_REV_ON_3430_3530       0x3C
-#define OMAP_I2C_REV_ON_3630_4430       0x40
+#define OMAP_I2C_REV_ON_2430            0x00000036
+#define OMAP_I2C_REV_ON_3430_3530       0x0000003C
+#define OMAP_I2C_REV_ON_3630            0x00000040
+#define OMAP_I2C_REV_ON_4430_PLUS       0x50400002
 
 /* timeout waiting for the controller to respond */
 #define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))
@@ -203,7 +204,7 @@ struct omap_i2c_dev {
                                                  * fifo_size==0 implies no fifo
                                                  * if set, should be trsh+1
                                                  */
-        u8                      rev;
+        u32                     rev;
         unsigned                b_hw:1;         /* bad h/w fixes */
         unsigned                receiver:1;     /* true when we're in receiver mode */
         u16                     iestate;        /* Saved interrupt register */
@@ -493,7 +494,7 @@ static void omap_i2c_resize_fifo(struct omap_i2c_dev *dev, u8 size, bool is_rx)
 
         omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
 
-        if (dev->rev < OMAP_I2C_REV_ON_3630_4430)
+        if (dev->rev < OMAP_I2C_REV_ON_3630)
                 dev->b_hw = 1; /* Enable hardware fixes */
 
         /* calculate wakeup latency constraint for MPU */
@@ -1051,6 +1052,16 @@ static const struct of_device_id omap_i2c_of_match[] = {
 MODULE_DEVICE_TABLE(of, omap_i2c_of_match);
 #endif
 
+#define OMAP_I2C_SCHEME(rev)            ((rev & 0xc000) >> 14)
+
+#define OMAP_I2C_REV_SCHEME_0_MAJOR(rev) (rev >> 4)
+#define OMAP_I2C_REV_SCHEME_0_MINOR(rev) (rev & 0xf)
+
+#define OMAP_I2C_REV_SCHEME_1_MAJOR(rev) ((rev & 0x0700) >> 7)
+#define OMAP_I2C_REV_SCHEME_1_MINOR(rev) (rev & 0x1f)
+#define OMAP_I2C_SCHEME_0               0
+#define OMAP_I2C_SCHEME_1               1
+
 static int __devinit
 omap_i2c_probe(struct platform_device *pdev)
 {
@@ -1063,6 +1074,8 @@ omap_i2c_probe(struct platform_device *pdev)
         const struct of_device_id *match;
         int irq;
         int r;
+        u32 rev;
+        u16 minor, major;
 
         /* NOTE: driver uses the static register mapping */
         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1127,11 +1140,6 @@ omap_i2c_probe(struct platform_device *pdev)
 
         dev->reg_shift = (dev->flags >> OMAP_I2C_FLAG_BUS_SHIFT__SHIFT) & 3;
 
-        if (dev->dtrev == OMAP_I2C_IP_VERSION_2)
-                dev->regs = (u8 *)reg_map_ip_v2;
-        else
-                dev->regs = (u8 *)reg_map_ip_v1;
-
         pm_runtime_enable(dev->dev);
         pm_runtime_set_autosuspend_delay(dev->dev, OMAP_I2C_PM_TIMEOUT);
         pm_runtime_use_autosuspend(dev->dev);
@@ -1140,7 +1148,31 @@ omap_i2c_probe(struct platform_device *pdev)
         if (IS_ERR_VALUE(r))
                 goto err_free_mem;
 
-        dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
+        /*
+         * Read the Rev hi bit-[15:14] ie scheme this is 1 indicates ver2.
+         * On omap1/3/2 Offset 4 is IE Reg the bit [15:14] is 0 at reset.
+         * Also since the omap_i2c_read_reg uses reg_map_ip_* a
+         * raw_readw is done.
+         */
+        rev = __raw_readw(dev->base + 0x04);
+
+        switch (OMAP_I2C_SCHEME(rev)) {
+        case OMAP_I2C_SCHEME_0:
+                dev->regs = (u8 *)reg_map_ip_v1;
+                dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG);
+                minor = OMAP_I2C_REV_SCHEME_0_MAJOR(dev->rev);
+                major = OMAP_I2C_REV_SCHEME_0_MAJOR(dev->rev);
+                break;
+        case OMAP_I2C_SCHEME_1:
+                /* FALLTHROUGH */
+        default:
+                dev->regs = (u8 *)reg_map_ip_v2;
+                rev = (rev << 16) |
+                        omap_i2c_read_reg(dev, OMAP_I2C_IP_V2_REVNB_LO);
+                minor = OMAP_I2C_REV_SCHEME_1_MINOR(rev);
+                major = OMAP_I2C_REV_SCHEME_1_MAJOR(rev);
+                dev->rev = rev;
+        }
 
         dev->errata = 0;
 
@@ -1165,7 +1197,7 @@ omap_i2c_probe(struct platform_device *pdev)
 
                 dev->fifo_size = (dev->fifo_size / 2);
 
-                if (dev->rev < OMAP_I2C_REV_ON_3630_4430)
+                if (dev->rev < OMAP_I2C_REV_ON_3630)
                         dev->b_hw = 1; /* Enable hardware fixes */
 
                 /* calculate wakeup latency constraint for MPU */
@@ -1209,7 +1241,7 @@ omap_i2c_probe(struct platform_device *pdev)
         }
 
         dev_info(dev->dev, "bus %d rev%d.%d.%d at %d kHz\n", adap->nr,
-                 dev->dtrev, dev->rev >> 4, dev->rev & 0xf, dev->speed);
+                 dev->dtrev, major, minor, dev->speed);
 
         of_i2c_register_devices(adap);
 
@@ -1275,6 +1307,9 @@ static int omap_i2c_runtime_resume(struct device *dev)
         struct platform_device *pdev = to_platform_device(dev);
         struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
 
+        if (!_dev->regs)
+                return 0;
+
         if (_dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
                 omap_i2c_write_reg(_dev, OMAP_I2C_CON_REG, 0);
                 omap_i2c_write_reg(_dev, OMAP_I2C_PSC_REG, _dev->pscstate);