[PATCH RESEND v6 15/17] power: supply: bd71828: Support wider register addresses

Matti Vaittinen
2025-12-15T13:21:14Z

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From: Matti Vaittinen <mazziesaccount@gmail.com>

The BD71828 power-supply driver assumes register addresses to be 8-bit.
The new BD72720 will use stacked register maps to hide paging which is
done using secondary I2C slave address. This requires use of 9-bit
register addresses in the power-supply driver (added offset 0x100 to
the 8-bit hardware register addresses).

The cost is slightly used memory consumption as the members in the
struct pwr_regs will be changed from u8 to unsigned int, which means 3
byte increase / member / instance.
This is currently 14 members (expected to possibly be increased when
adding new variants / new functionality which may introduce new
registers, but not expected to grow much) and 2 instances (will be 3
instances when BD72720 gets added).

So, even if the number of registers grew to 50 it'd be 150 bytes /
instance. Assuming we eventually supported 5 variants, it'd be
5 * 150 bytes, which stays very reasonable considering systems we are
dealing with.

As a side note, we can reduce the "wasted space / member / instance" from
3 bytes to 1 byte, by using u16 instead of the unsigned int if needed. I
rather use unsigned int to be initially prepared for devices with 32 bit
registers if there is no need to count bytes.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
---
Revision history:
v2 => :
- No changes

RFCv1 => v2:
- New patch
---
drivers/power/supply/bd71828-power.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/power/supply/bd71828-power.c b/drivers/power/supply/bd71828-power.c
index f667baedeb77..ce73c0f48397 100644
--- a/drivers/power/supply/bd71828-power.c
+++ b/drivers/power/supply/bd71828-power.c
@@ -44,19 +44,19 @@
#define VBAT_LOW_TH 0x00D4

struct pwr_regs {
- u8 vbat_avg;
- u8 ibat;
- u8 ibat_avg;
- u8 btemp_vth;
- u8 chg_state;
- u8 bat_temp;
- u8 dcin_stat;
- u8 dcin_collapse_limit;
- u8 chg_set1;
- u8 chg_en;
- u8 vbat_alm_limit_u;
- u8 conf;
- u8 vdcin;
+ unsigned int vbat_avg;
+ unsigned int ibat;
+ unsigned int ibat_avg;
+ unsigned int btemp_vth;
+ unsigned int chg_state;
+ unsigned int bat_temp;
+ unsigned int dcin_stat;
+ unsigned int dcin_collapse_limit;
+ unsigned int chg_set1;
+ unsigned int chg_en;
+ unsigned int vbat_alm_limit_u;
+ unsigned int conf;
+ unsigned int vdcin;
};

static const struct pwr_regs pwr_regs_bd71828 = {