Re: [PATCH v5 5/5] i2c: mediatek: Add i2c support for MediaTek MT8183

Nicolas Boichat
2019-03-06T10:52:52Z

On Tue, Feb 26, 2019 at 9:11 PM Qii Wang <qii.wang@mediatek.com> wrote:
>
> Add i2c compatible for MT8183. Compare to MT2712 i2c controller,
> MT8183 has different register offsets. Ltiming_reg is added to
> adjust low width of SCL. Arb clock and dma_sync are needed.
>
> Signed-off-by: Qii Wang <qii.wang@mediatek.com>
> ---
> drivers/i2c/busses/i2c-mt65xx.c | 53 +++++++++++++++++++++++++++++++++++++--
> 1 file changed, 51 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index 75d88e1..82eedbd 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -133,6 +133,8 @@ enum I2C_REGS_OFFSET {
> OFFSET_DEBUGCTRL,
> OFFSET_TRANSFER_LEN_AUX,
> OFFSET_CLOCK_DIV,
> + /* MT8183 only regs */
> + OFFSET_LTIMING,
> };
>
> static const u16 mt_i2c_regs_v1[] = {
> @@ -162,6 +164,32 @@ enum I2C_REGS_OFFSET {
> [OFFSET_CLOCK_DIV] = 0x70,
> };
>
> +static const u16 mt_i2c_regs_v2[] = {
> + [OFFSET_DATA_PORT] = 0x0,
> + [OFFSET_SLAVE_ADDR] = 0x4,
> + [OFFSET_INTR_MASK] = 0x8,
> + [OFFSET_INTR_STAT] = 0xc,
> + [OFFSET_CONTROL] = 0x10,
> + [OFFSET_TRANSFER_LEN] = 0x14,
> + [OFFSET_TRANSAC_LEN] = 0x18,
> + [OFFSET_DELAY_LEN] = 0x1c,
> + [OFFSET_TIMING] = 0x20,
> + [OFFSET_START] = 0x24,
> + [OFFSET_EXT_CONF] = 0x28,
> + [OFFSET_LTIMING] = 0x2c,
> + [OFFSET_HS] = 0x30,
> + [OFFSET_IO_CONFIG] = 0x34,
> + [OFFSET_FIFO_ADDR_CLR] = 0x38,
> + [OFFSET_TRANSFER_LEN_AUX] = 0x44,
> + [OFFSET_CLOCK_DIV] = 0x48,
> + [OFFSET_SOFTRESET] = 0x50,
> + [OFFSET_DEBUGSTAT] = 0xe0,
> + [OFFSET_DEBUGCTRL] = 0xe8,
> + [OFFSET_FIFO_STAT] = 0xf4,
> + [OFFSET_FIFO_THRESH] = 0xf8,
> + [OFFSET_DCM_EN] = 0xf88,
> +};
> +
> struct mtk_i2c_compatible {
> const struct i2c_adapter_quirks *quirks;
> const u16 *regs;
> @@ -195,6 +223,7 @@ struct mtk_i2c {
> enum mtk_trans_op op;
> u16 timing_reg;
> u16 high_speed_reg;
> + u16 ltiming_reg;
> unsigned char auto_restart;
> bool ignore_restart_irq;
> const struct mtk_i2c_compatible *dev_comp;
> @@ -271,12 +300,24 @@ struct mtk_i2c {
> .dma_sync = 0,
> };
>
> +static const struct mtk_i2c_compatible mt8183_compat = {
> + .regs = mt_i2c_regs_v2,
> + .pmic_i2c = 0,
> + .dcm = 0,
> + .auto_restart = 1,
> + .aux_len_reg = 1,
> + .support_33bits = 1,
> + .timing_adjust = 1,
> + .dma_sync = 1,
> +};
> +
> static const struct of_device_id mtk_i2c_of_match[] = {
> { .compatible = "mediatek,mt2712-i2c", .data = &mt2712_compat },
> { .compatible = "mediatek,mt6577-i2c", .data = &mt6577_compat },
> { .compatible = "mediatek,mt6589-i2c", .data = &mt6589_compat },
> { .compatible = "mediatek,mt7622-i2c", .data = &mt7622_compat },
> { .compatible = "mediatek,mt8173-i2c", .data = &mt8173_compat },
> + { .compatible = "mediatek,mt8183-i2c", .data = &mt8183_compat },
> {}
> };
> MODULE_DEVICE_TABLE(of, mtk_i2c_of_match);
> @@ -361,6 +402,8 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
>
> mtk_i2c_writew(i2c, i2c->timing_reg, OFFSET_TIMING);
> mtk_i2c_writew(i2c, i2c->high_speed_reg, OFFSET_HS);
> + if (i2c->dev_comp->regs == mt_i2c_regs_v2)
> + mtk_i2c_writew(i2c, i2c->ltiming_reg, OFFSET_LTIMING);

Matthias wasn't super happy with this. One way is to add another field
in the compatible string. Another may be to have
mt_i2c_regs_v1[OFFSET_LTIMING] point at, say 0xffff (#define this as
I2C_REG_INVALID or something), and test for that?

Either way would scale better if we end up with more than 2 versions
of the register set in the future.

> /* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
> if (i2c->have_pmic)
> @@ -460,6 +503,8 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> unsigned int clk_src;
> unsigned int step_cnt;
> unsigned int sample_cnt;
> + unsigned int l_step_cnt;
> + unsigned int l_sample_cnt;
> unsigned int target_speed;
> int ret;
>
> @@ -469,11 +514,11 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> if (target_speed > MAX_FS_MODE_SPEED) {
> /* Set master code speed register */
> ret = mtk_i2c_calculate_speed(i2c, clk_src, MAX_FS_MODE_SPEED,
> - &step_cnt, &sample_cnt);
> + &l_step_cnt, &l_sample_cnt);
> if (ret < 0)
> return ret;
>
> - i2c->timing_reg = (sample_cnt << 8) | step_cnt;
> + i2c->timing_reg = (l_sample_cnt << 8) | l_step_cnt;
>
> /* Set the high speed mode register */
> ret = mtk_i2c_calculate_speed(i2c, clk_src, target_speed,
> @@ -483,6 +528,8 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
>
> i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
> (sample_cnt << 12) | (step_cnt << 8);
> + i2c->ltiming_reg = (l_sample_cnt << 6) | l_step_cnt |
> + (sample_cnt << 12) | (step_cnt << 9);
> } else {
> ret = mtk_i2c_calculate_speed(i2c, clk_src, target_speed,
> &step_cnt, &sample_cnt);
> @@ -493,6 +540,8 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
>
> /* Disable the high speed transaction */
> i2c->high_speed_reg = I2C_TIME_CLR_VALUE;
> +
> + i2c->ltiming_reg = (sample_cnt << 6) | step_cnt;
> }
>
> return 0;
> --
> 1.7.9.5
>