Hi Leela,
> 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 <adur...@chromium.org>
> Signed-off-by: Simon Glass <s...@chromium.org>
> Signed-off-by: Leela Krishna Amudala <l.kris...@samsung.com>
> Reviewed-by: Doug Anderson <diand...@google.com>
> ---
> 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 47c606f..c22e01f 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;
> +
> + old_bus = i2c_get_bus_num();
> + if (old_bus != p->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)
> +{
> + 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);
I'm wondering if setting the bus before each, single i2c write (when we
usually perform several writes to one device) will not be an overkill
(we search the ll_entry_count linker list each time to find max i2c
adapter names) ?
The i2c_set_bus_num() is now done at pmic_probe(), but this also
introduces overkill for "probing" each device when we want to read from
it.
As a side note - I would appreciate if you would add Stefano Babic and
me on the Cc (as we are listed at e.g. power_core.c).
> + pmic_deselect(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);
> + 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) @@ -117,9 +163,15 @@ int
> pmic_reg_update(struct pmic *p, int reg, uint regval)
> 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;
> 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;
> }
--
Best regards,
Lukasz Majewski
Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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