[U-Boot] [PATCH 02/16] pmic:i2c: Add I2C byte order to PMIC framework

Stefano Babic
2012-09-17T09:33:20Z

On 14/09/2012 17:40, Lukasz Majewski wrote:
> Since the pmic_reg_read is the u32 value, the order in which bytes
> are placed to form u32 value is important.
>
> This commit adds the reverse (which is default) and normal byte order.
>
> Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---

Hi,

> drivers/misc/pmic_i2c.c | 31 ++++++++++++++++++++++++-------
> include/pmic.h | 3 +++
> 2 files changed, 27 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/misc/pmic_i2c.c b/drivers/misc/pmic_i2c.c
> index e74c372..1aa5b7b 100644
> --- a/drivers/misc/pmic_i2c.c
> +++ b/drivers/misc/pmic_i2c.c
> @@ -40,13 +40,24 @@ int pmic_reg_write(struct pmic *p, u32 reg, u32 val)
>
> switch (pmic_i2c_tx_num) {
> case 3:
> - buf[0] = (val >> 16) & 0xff;
> - buf[1] = (val >> 8) & 0xff;
> - buf[2] = val & 0xff;
> + if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL) {
> + buf[2] = (val >> 16) & 0xff;
> + buf[1] = (val >> 8) & 0xff;
> + buf[0] = val & 0xff;
> + } else {
> + buf[0] = (val >> 16) & 0xff;
> + buf[1] = (val >> 8) & 0xff;
> + buf[2] = val & 0xff;
> + }
> break;
> case 2:
> - buf[0] = (val >> 8) & 0xff;
> - buf[1] = val & 0xff;
> + if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL) {
> + buf[1] = (val >> 8) & 0xff;
> + buf[0] = val & 0xff;
> + } else {
> + buf[0] = (val >> 8) & 0xff;
> + buf[1] = val & 0xff;
> + }
> break;
> case 1:
> buf[0] = val & 0xff;
> @@ -75,10 +86,16 @@ int pmic_reg_read(struct pmic *p, u32 reg, u32 *val)
>
> switch (pmic_i2c_tx_num) {
> case 3:
> - ret_val = buf[0] << 16 | buf[1] << 8 | buf[2];
> + if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL)
> + ret_val = buf[2] << 16 | buf[1] << 8 | buf[0];
> + else
> + ret_val = buf[0] << 16 | buf[1] << 8 | buf[2];
> break;
> case 2:
> - ret_val = buf[0] << 8 | buf[1];
> + if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL)
> + ret_val = buf[1] << 8 | buf[0];
> + else
> + ret_val = buf[0] << 8 | buf[1];
> break;
> case 1:
> ret_val = buf[0];
> diff --git a/include/pmic.h b/include/pmic.h
> index 6a05b40..2166f73 100644
> --- a/include/pmic.h
> +++ b/include/pmic.h
> @@ -27,11 +27,13 @@
> enum { PMIC_I2C, PMIC_SPI, };
> enum { I2C_PMIC, I2C_NUM, };
> enum { PMIC_READ, PMIC_WRITE, };
> +enum { PMIC_BYTE_ORDER_REVERSED, PMIC_BYTE_ORDER_NORMAL, };
>
> struct p_i2c {
> unsigned char addr;
> unsigned char *buf;
> unsigned char tx_num;
> + unsigned char byte_order;

I can imagine we could have the same issue with SPI and not only with
I2C. The byte order is not strictly related to the interface type, and I
think this should add to the "struct pmic" instead of the "struct p_i2c".

Regards,
Stefano Babic

--
=====================================================================
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================