Re: [U-Boot] [PATCH V3 2/6] power: Explicitly select pmic device's bus

Dear Leela Krishna Amudala,

On 12/11/13 19:04, Leela Krishna Amudala wrote:

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 | 62 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 57 insertions(+), 5 deletions(-)

diff --git a/drivers/power/power_i2c.c b/drivers/power/power_i2c.c index ac76870..3cafa4d 100644 --- a/drivers/power/power_i2c.c +++ b/drivers/power/power_i2c.c @@ -16,9 +16,45 @@ #include <i2c.h> #include <compiler.h>

+static int pmic_select(struct pmic *p) +{

• int ret, old_bus;

I think, old prefix is meaningless. please fix it globally.

• old_bus = i2c_get_bus_num();
• if (old_bus != p->bus) {

How about return immediately if get a bus.

if (old_bus == p->bus) return old_bus;

• debug("%s: Select bus %d\n", __func__, p->bus);
  

• ret = i2c_set_bus_num(p->bus);
  

• if (ret) {
  

• 	debug("%s: Cannot select pmic %s, err %d\n",
  

• 	      __func__, p->name, ret);
  

• 	return -1;
  

• }
  

• }
• return old_bus;

+}

+static int pmic_deselect(int old_bus)

in your patch, you never check a return value. then is it void function or wrong usage?

And I think pmic_deselect function is almost same with pmic_select. If you change the parameter for pmic_select to "int bus" then, What is different with pmic_select?

for example.

bus = pmic_select(p->bus); /* do something */ pmic_deselect(bus);

is same with.

bus = pmic_select(p->bus); /* do something */ pmic_select(bus);

How do you think?

+{

• int ret;
• if (old_bus != i2c_get_bus_num()) {

• ret = i2c_set_bus_num(old_bus);
  

• debug("%s: Select bus %d\n", __func__, old_bus);
  

• if (ret) {
  

• 	debug("%s: Cannot restore i2c bus, err %d\n",
  

• 	      __func__, ret);
  

• 	return -1;
  

• }
  

• }
• return 0;

+}

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 +88,33 @@ 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);
• if (old_bus < 0) return -1;

• return 0;

• ret = i2c_write(pmic_i2c_addr, reg, 1, buf, pmic_i2c_tx_num);
• pmic_deselect(old_bus);

please add blank line.

• 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);

• if (old_bus < 0) return -1;

• ret = i2c_read(pmic_i2c_addr, reg, 1, buf, pmic_i2c_tx_num);

• pmic_deselect(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 +144,15 @@ 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);
• if (old_bus < 0)

• return -1;
  

please add blank line.

debug("Bus: %d PMIC:%s probed!\n", p->bus, p->name);

• if (i2c_probe(pmic_i2c_addr)) {

• ret = i2c_probe(pmic_i2c_addr);
• pmic_deselect(old_bus);
• if (ret) { printf("Can't find PMIC:%s\n", p->name); return -1; }

Thanks, Minkyu Kang.