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[U-Boot,V4,2/6] power: Explicitly select pmic device's bus

Message ID 1389008957-21493-3-git-send-email-l.krishna@samsung.com
State Changes Requested
Delegated to: Minkyu Kang
Headers show

Commit Message

Leela Krishna Amudala Jan. 6, 2014, 11:49 a.m. UTC 
The current pmic i2c code assumes the current i2c bus is
the same as the pmic device's bus. There is nothing ensuring
that to be true. Therefore, select the proper bus before performing
a transaction.

Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Reviewed-by: Doug Anderson <dianders@google.com>
Acked-by: Simon Glass <sjg@chromium.org>
---
 drivers/power/power_i2c.c |   48 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 43 insertions(+), 5 deletions(-)
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Patch

diff --git a/drivers/power/power_i2c.c b/drivers/power/power_i2c.c
index ac76870..e4986bb 100644
--- a/drivers/power/power_i2c.c
+++ b/drivers/power/power_i2c.c
@@ -16,9 +16,29 @@ 
 #include <i2c.h>
 #include <compiler.h>
 
+static int pmic_select(int bus)
+{
+	int ret, old_bus;
+
+	old_bus = i2c_get_bus_num();
+
+	if (old_bus == bus)
+		return old_bus;
+
+	debug("%s: Select bus %d\n", __func__, bus);
+	ret = i2c_set_bus_num(bus);
+	if (ret) {
+		debug("%s: Cannot select pmic, err %d\n", __func__, ret);
+		return -1;
+	}
+
+	return old_bus;
+}
+
 int pmic_reg_write(struct pmic *p, u32 reg, u32 val)
 {
 	unsigned char buf[4] = { 0 };
+	int ret, old_bus;
 
 	if (check_reg(p, reg))
 		return -1;
@@ -52,23 +72,34 @@  int pmic_reg_write(struct pmic *p, u32 reg, u32 val)
 		return -1;
 	}
 
-	if (i2c_write(pmic_i2c_addr, reg, 1, buf, pmic_i2c_tx_num))
+	old_bus = pmic_select(p->bus);
+	if (old_bus < 0)
 		return -1;
 
-	return 0;
+	ret = i2c_write(pmic_i2c_addr, reg, 1, buf, pmic_i2c_tx_num);
+	pmic_select(old_bus);
+
+	return ret;
 }
 
 int pmic_reg_read(struct pmic *p, u32 reg, u32 *val)
 {
 	unsigned char buf[4] = { 0 };
 	u32 ret_val = 0;
+	int ret, old_bus;
 
 	if (check_reg(p, reg))
 		return -1;
 
-	if (i2c_read(pmic_i2c_addr, reg, 1, buf, pmic_i2c_tx_num))
+	old_bus = pmic_select(p->bus);
+	if (old_bus < 0)
 		return -1;
 
+	ret = i2c_read(pmic_i2c_addr, reg, 1, buf, pmic_i2c_tx_num);
+	pmic_select(old_bus);
+	if (ret)
+		return ret;
+
 	switch (pmic_i2c_tx_num) {
 	case 3:
 		if (p->sensor_byte_order == PMIC_SENSOR_BYTE_ORDER_BIG)
@@ -98,9 +129,16 @@  int pmic_reg_read(struct pmic *p, u32 reg, u32 *val)
 
 int pmic_probe(struct pmic *p)
 {
-	i2c_set_bus_num(p->bus);
+	int ret, old_bus;
+
+	old_bus = pmic_select(p->bus);
+	if (old_bus < 0)
+		return -1;
+
 	debug("Bus: %d PMIC:%s probed!\n", p->bus, p->name);
-	if (i2c_probe(pmic_i2c_addr)) {
+	ret = i2c_probe(pmic_i2c_addr);
+	pmic_select(old_bus);
+	if (ret) {
 		printf("Can't find PMIC:%s\n", p->name);
 		return -1;
 	}