[PATCH 1/2] i2c: omap: Fix the revision register read

Shubhrajyoti D
2012-11-02T10:39:44Z

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>
---
drivers/i2c/busses/i2c-omap.c | 59 ++++++++++++++++++++++++++++++++---------
1 files changed, 46 insertions(+), 13 deletions(-)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index db31eae..d8e7709 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))
@@ -202,7 +203,7 @@ 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 */
@@ -490,7 +491,7 @@ 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 */
@@ -1052,6 +1053,14 @@ 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)
+
static int __devinit
omap_i2c_probe(struct platform_device *pdev)
{
@@ -1064,6 +1073,8 @@ 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);
@@ -1117,11 +1128,6 @@ 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);
@@ -1130,7 +1136,31 @@ 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 omap3 Offset 4 is IE Reg the bit [15:14] is XDR_IE which 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 0:
+ dev->regs = (u8 *)reg_map_ip_v1;
+ dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
+ minor = OMAP_I2C_REV_SCHEME_0_MAJOR(dev->rev);
+ major = OMAP_I2C_REV_SCHEME_0_MAJOR(dev->rev);
+ break;
+ case 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;

@@ -1155,7 +1185,7 @@ 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 */
@@ -1198,7 +1228,7 @@ 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);

@@ -1264,6 +1294,9 @@ 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);
--
1.7.5.4