Re: [PATCH] i2c: add pmic_reg_read() for PBL use

[Sascha Hauer <sha@pengutronix.de>]

On Tue, Dec 19, 2023 at 05:21:35PM +0100, Ahmad Fatoum wrote:
> Hello Bastian,
> 
> On 19.12.23 17:11, Bastian Krause wrote:
> > Add a common PMIC read function to PBL which allows easy porting of
> > U-Boot's pmic_reg_read() in lowlevel board code.
> > 
> > Signed-off-by: Bastian Krause <bst@pengutronix.de>
> > ---
> >  include/pbl/pmic.h | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/include/pbl/pmic.h b/include/pbl/pmic.h
> > index 0f882c5649d..bd0583370ec 100644
> > --- a/include/pbl/pmic.h
> > +++ b/include/pbl/pmic.h
> > @@ -9,6 +9,27 @@ struct pmic_config {
> >  	u8 val;
> >  };
> >  
> > +static void pmic_reg_read(struct pbl_i2c *i2c, int addr, u8 reg, void *buf)
> 
> This should be static inline to avoid warnings for boards that don't use it.
> 
> > +{
> > +	int ret;
> > +	struct i2c_msg msg[] = {
> > +		{
> > +			.addr = addr,
> > +			.buf = &reg,
> > +			.len = 1,
> > +		}, {
> > +			.addr = addr,
> > +			.flags = I2C_M_RD,
> > +			.buf = buf,
> 
> U-Boot has buf of type u32 *. In your barebox implementation, only the
> first byte is written, so this leaves 3 bytes potentially uninitialized.
> 
> You likely want to change void *buf to u32 *val and then
> 
>   u8 buf[1];
>   /* i2c_xfer... */
>   *val = buf[0];

When *buf is assumed to be a single byte only anyway then we can change
its type to u8 *

Sascha

> 
> > +			.len = 1,
> > +		},
> > +	};
> > +
> > +	ret = pbl_i2c_xfer(i2c, msg, ARRAY_SIZE(msg));
> > +	if (ret != ARRAY_SIZE(msg))
> > +		pr_err("Failed to read from pmic@%x: %d\n", addr, ret);
> > +}
> 
> Cheers,
> Ahmad
> 
> > +
> >  static void pmic_reg_write(struct pbl_i2c *i2c, int addr, u8 reg, u8 val)
> >  {
> >  	int ret;
> 
> -- 
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> 
> 
> 

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