Re: [PATCH v3] i2c: mt8173: add 4GB mode support in i2c driver.

From: Yingjoe Chen
Date: Fri Jan 29 2016 - 04:51:08 EST


On Fri, 2016-01-29 at 09:35 +0800, Liguo Zhang wrote:
> If 4GB mode is enable, we should add 4gb mode support in i2c driver.

nit: enabled
However, after looking at it longer, the commit message doesn't make
much sense to me.

> Set 4GB mode register to support 4GB mode.
>
> Signed-off-by: Liguo Zhang <liguo.zhang@xxxxxxxxxxxx>
> ---
> change in v3:
> Only inline the computation of reg_4g_mode in mtk_i2c_set_4g_mode().
> change in v2:
> Define a static inline funtion mtk_i2c_set_4g_mode() for support 4g mode.
> ---
> drivers/i2c/busses/i2c-mt65xx.c | 42 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index aec8e6c..3c484f0 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -60,6 +60,7 @@
> #define I2C_DMA_INT_FLAG_NONE 0x0000
> #define I2C_DMA_CLR_FLAG 0x0000
> #define I2C_DMA_HARD_RST 0x0002
> +#define I2C_DMA_4G_MODE 0x0001
>
> #define I2C_DEFAULT_SPEED 100000 /* hz */
> #define MAX_FS_MODE_SPEED 400000
> @@ -88,6 +89,8 @@ enum DMA_REGS_OFFSET {
> OFFSET_RX_MEM_ADDR = 0x20,
> OFFSET_TX_LEN = 0x24,
> OFFSET_RX_LEN = 0x28,
> + OFFSET_TX_4G_MODE = 0x54,
> + OFFSET_RX_4G_MODE = 0x58,
> };
>
> enum i2c_trans_st_rs {
> @@ -133,6 +136,7 @@ struct mtk_i2c_compatible {
> unsigned char dcm: 1;
> unsigned char auto_restart: 1;
> unsigned char aux_len_reg: 1;
> + unsigned char support_33bits: 1;
> };
>
> struct mtk_i2c {
> @@ -182,6 +186,7 @@ static const struct mtk_i2c_compatible mt6577_compat = {
> .dcm = 1,
> .auto_restart = 0,
> .aux_len_reg = 0,
> + .support_33bits = 0,
> };
>
> static const struct mtk_i2c_compatible mt6589_compat = {
> @@ -190,6 +195,7 @@ static const struct mtk_i2c_compatible mt6589_compat = {
> .dcm = 0,
> .auto_restart = 0,
> .aux_len_reg = 0,
> + .support_33bits = 0,
> };
>
> static const struct mtk_i2c_compatible mt8173_compat = {
> @@ -198,6 +204,7 @@ static const struct mtk_i2c_compatible mt8173_compat = {
> .dcm = 1,
> .auto_restart = 1,
> .aux_len_reg = 1,
> + .support_33bits = 1,
> };
>
> static const struct of_device_id mtk_i2c_of_match[] = {
> @@ -366,6 +373,11 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk,
> return 0;
> }
>
> +static inline u32 mtk_i2c_set_4g_mode(dma_addr_t addr)
> +{
> + return (addr & BIT(32)) ? I2C_DMA_4G_MODE : I2C_DMA_CLR_FLAG;
> +}
> +

#define BIT(nr) (1UL << (nr))
#define BIT_ULL(nr) (1ULL << (nr))

#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))


I think you should use BIT_ULL.


> static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> int num, int left_num)
> {
> @@ -373,6 +385,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> u16 start_reg;
> u16 control_reg;
> u16 restart_flag = 0;
> + u32 reg_4g_mode = 0;


unnecessary init.

Joe.C