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authorPaul Walmsley <paul@pwsan.com>2008-11-21 13:39:55 -0800
committerTony Lindgren <tony@atomide.com>2008-11-21 13:39:55 -0800
commitfdd07fe6f6fe54250d8b1126b42ebdc72d938f05 (patch)
tree9f52a8091681f4c90eac953d5daacc378e6b2844 /drivers/i2c
parent9c76b878eb3f837ff98b37aa254e6cc7942e946b (diff)
i2c-omap: reprogram OCP_SYSCONFIG register after reset
The I2C controller clears its OCP_SYSCONFIG register after an OCP soft reset. Reprogram OCP_SYSCONFIG for maximum power savings on rev3.6 controllers and beyond. On 2430, this involves setting the module AUTOIDLE bit. On 3430, this includes module AUTOIDLE, wakeup enable, slave smart-idle, and considers only the module functional clock state for idle-ack. Boot-tested on 2430SDP and 3430SDP. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Richard Woodruff <r-woodruff2@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-omap.c40
1 files changed, 34 insertions, 6 deletions
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 3ac510d9c9b..b2023541587 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -123,11 +123,19 @@
#define OMAP_I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive out */
#endif
-/* I2C System Status register (OMAP_I2C_SYSS): */
-#define OMAP_I2C_SYSS_RDONE (1 << 0) /* Reset Done */
+/* OCP_SYSSTATUS bit definitions */
+#define SYSS_RESETDONE_MASK (1 << 0)
+
+/* OCP_SYSCONFIG bit definitions */
+#define SYSC_CLOCKACTIVITY_MASK (0x3 << 8)
+#define SYSC_SIDLEMODE_MASK (0x3 << 3)
+#define SYSC_ENAWAKEUP_MASK (1 << 2)
+#define SYSC_SOFTRESET_MASK (1 << 1)
+#define SYSC_AUTOIDLE_MASK (1 << 0)
+
+#define SYSC_IDLEMODE_SMART 0x2
+#define SYSC_CLOCKACTIVITY_FCLK 0x2
-/* I2C System Configuration Register (OMAP_I2C_SYSC): */
-#define OMAP_I2C_SYSC_SRST (1 << 1) /* Soft Reset */
struct omap_i2c_dev {
struct device *dev;
@@ -239,13 +247,13 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
unsigned long internal_clk = 0;
if (dev->rev >= OMAP_I2C_REV_2) {
- omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, OMAP_I2C_SYSC_SRST);
+ omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
/* For some reason we need to set the EN bit before the
* reset done bit gets set. */
timeout = jiffies + OMAP_I2C_TIMEOUT;
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
- OMAP_I2C_SYSS_RDONE)) {
+ SYSS_RESETDONE_MASK)) {
if (time_after(jiffies, timeout)) {
dev_warn(dev->dev, "timeout waiting "
"for controller reset\n");
@@ -253,6 +261,26 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
}
msleep(1);
}
+
+ /* SYSC register is cleared by the reset; rewrite it */
+ if (dev->rev == OMAP_I2C_REV_ON_2430) {
+
+ omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
+ SYSC_AUTOIDLE_MASK);
+
+ } else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
+ u32 v;
+
+ v = SYSC_AUTOIDLE_MASK;
+ v |= SYSC_ENAWAKEUP_MASK;
+ v |= (SYSC_IDLEMODE_SMART <<
+ __ffs(SYSC_SIDLEMODE_MASK));
+ v |= (SYSC_CLOCKACTIVITY_FCLK <<
+ __ffs(SYSC_CLOCKACTIVITY_MASK));
+
+ omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, v);
+
+ }
}
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);