lkml.org 
[lkml]   [2019]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/2] i2c: mediatek: Add i2c AC timing adjust support
Date
This patch adds some I2C timing registers to meet I2C spec, it
configures these registers according to information passed via DT.

Signed-off-by: Qii Wang <qii.wang@mediatek.com>
---
drivers/i2c/busses/i2c-mt65xx.c | 94 ++++++++++++++++++++++++++++++++++-----
1 file changed, 82 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 745b0d0..f4bf753 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -134,6 +134,12 @@ enum I2C_REGS_OFFSET {
OFFSET_TRANSFER_LEN_AUX,
OFFSET_CLOCK_DIV,
OFFSET_LTIMING,
+ OFFSET_SCL_HIGH_LOW_RATIO,
+ OFFSET_HS_SCL_HIGH_LOW_RATIO,
+ OFFSET_SCL_MIS_COMP_POINT,
+ OFFSET_STA_STO_AC_TIMING,
+ OFFSET_HS_STA_STO_AC_TIMING,
+ OFFSET_SDA_TIMING,
};

static const u16 mt_i2c_regs_v1[] = {
@@ -161,6 +167,12 @@ enum I2C_REGS_OFFSET {
[OFFSET_DEBUGCTRL] = 0x68,
[OFFSET_TRANSFER_LEN_AUX] = 0x6c,
[OFFSET_CLOCK_DIV] = 0x70,
+ [OFFSET_SCL_HIGH_LOW_RATIO] = 0x74,
+ [OFFSET_HS_SCL_HIGH_LOW_RATIO] = 0x78,
+ [OFFSET_SCL_MIS_COMP_POINT] = 0x7C,
+ [OFFSET_STA_STO_AC_TIMING] = 0x80,
+ [OFFSET_HS_STA_STO_AC_TIMING] = 0x84,
+ [OFFSET_SDA_TIMING] = 0x88,
};

static const u16 mt_i2c_regs_v2[] = {
@@ -179,9 +191,11 @@ enum I2C_REGS_OFFSET {
[OFFSET_HS] = 0x30,
[OFFSET_IO_CONFIG] = 0x34,
[OFFSET_FIFO_ADDR_CLR] = 0x38,
+ [OFFSET_SDA_TIMING] = 0x3c,
[OFFSET_TRANSFER_LEN_AUX] = 0x44,
[OFFSET_CLOCK_DIV] = 0x48,
[OFFSET_SOFTRESET] = 0x50,
+ [OFFSET_SCL_MIS_COMP_POINT] = 0x90,
[OFFSET_DEBUGSTAT] = 0xe0,
[OFFSET_DEBUGCTRL] = 0xe8,
[OFFSET_FIFO_STAT] = 0xf4,
@@ -202,6 +216,17 @@ struct mtk_i2c_compatible {
unsigned char ltiming_adjust: 1;
};

+struct mtk_i2c_ac_timing {
+ u16 ext;
+ u16 inter_clk_div;
+ u16 scl_hl_ratio;
+ u16 hs_scl_hl_ratio;
+ u16 scl_mis_comp;
+ u16 sta_stop;
+ u16 hs_sta_stop;
+ u16 sda_timing;
+};
+
struct mtk_i2c {
struct i2c_adapter adap; /* i2c host adapter */
struct device *dev;
@@ -226,6 +251,7 @@ struct mtk_i2c {
u16 ltiming_reg;
unsigned char auto_restart;
bool ignore_restart_irq;
+ struct mtk_i2c_ac_timing ac_timing;
const struct mtk_i2c_compatible *dev_comp;
};

@@ -403,13 +429,40 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
if (i2c->dev_comp->dcm)
mtk_i2c_writew(i2c, I2C_DCM_DISABLE, OFFSET_DCM_EN);

- if (i2c->dev_comp->timing_adjust)
- mtk_i2c_writew(i2c, I2C_DEFAULT_CLK_DIV - 1, OFFSET_CLOCK_DIV);
-
mtk_i2c_writew(i2c, i2c->timing_reg, OFFSET_TIMING);
mtk_i2c_writew(i2c, i2c->high_speed_reg, OFFSET_HS);
- if (i2c->dev_comp->ltiming_adjust)
- mtk_i2c_writew(i2c, i2c->ltiming_reg, OFFSET_LTIMING);
+
+ if (i2c->dev_comp->timing_adjust) {
+ mtk_i2c_writew(i2c, i2c->ac_timing.ext, OFFSET_EXT_CONF);
+ mtk_i2c_writew(i2c, i2c->ac_timing.inter_clk_div - 1,
+ OFFSET_CLOCK_DIV);
+ mtk_i2c_writew(i2c, i2c->ac_timing.scl_mis_comp,
+ OFFSET_SCL_MIS_COMP_POINT);
+ mtk_i2c_writew(i2c, i2c->ac_timing.sda_timing,
+ OFFSET_SDA_TIMING);
+
+ if (i2c->dev_comp->ltiming_adjust) {
+ mtk_i2c_writew(i2c, i2c->timing_reg -
+ i2c->ac_timing.scl_hl_ratio,
+ OFFSET_TIMING);
+ mtk_i2c_writew(i2c, i2c->high_speed_reg -
+ ((i2c->ac_timing.hs_scl_hl_ratio) << 8),
+ OFFSET_HS);
+ mtk_i2c_writew(i2c, i2c->ltiming_reg +
+ ((i2c->ac_timing.hs_scl_hl_ratio) << 9) +
+ i2c->ac_timing.scl_hl_ratio,
+ OFFSET_LTIMING);
+ } else {
+ mtk_i2c_writew(i2c, i2c->ac_timing.scl_hl_ratio,
+ OFFSET_SCL_HIGH_LOW_RATIO);
+ mtk_i2c_writew(i2c, i2c->ac_timing.hs_scl_hl_ratio,
+ OFFSET_HS_SCL_HIGH_LOW_RATIO);
+ mtk_i2c_writew(i2c, i2c->ac_timing.sta_stop,
+ OFFSET_STA_STO_AC_TIMING);
+ mtk_i2c_writew(i2c, i2c->ac_timing.hs_sta_stop,
+ OFFSET_HS_STA_STO_AC_TIMING);
+ }
+ }

/* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
if (i2c->have_pmic)
@@ -592,12 +645,6 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,

mtk_i2c_writew(i2c, control_reg, OFFSET_CONTROL);

- /* set start condition */
- if (i2c->speed_hz <= I2C_DEFAULT_SPEED)
- mtk_i2c_writew(i2c, I2C_ST_START_CON, OFFSET_EXT_CONF);
- else
- mtk_i2c_writew(i2c, I2C_FS_START_CON, OFFSET_EXT_CONF);
-
addr_reg = i2c_8bit_addr_from_msg(msgs);
mtk_i2c_writew(i2c, addr_reg, OFFSET_SLAVE_ADDR);

@@ -889,6 +936,7 @@ static u32 mtk_i2c_functionality(struct i2c_adapter *adap)
static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
{
int ret;
+ u16 ac_timing[8] = {0};

ret = of_property_read_u32(np, "clock-frequency", &i2c->speed_hz);
if (ret < 0)
@@ -901,6 +949,28 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
if (i2c->clk_src_div == 0)
return -EINVAL;

+ if (i2c->dev_comp->timing_adjust) {
+ ret = of_property_read_u16_array(np, "ac-timing", ac_timing,
+ ARRAY_SIZE(ac_timing));
+ if (ret < 0) {
+ if (i2c->speed_hz <= I2C_DEFAULT_SPEED)
+ i2c->ac_timing.ext = I2C_ST_START_CON;
+ else
+ i2c->ac_timing.ext = I2C_FS_START_CON;
+
+ i2c->ac_timing.inter_clk_div = I2C_DEFAULT_CLK_DIV;
+ } else {
+ i2c->ac_timing.ext = ac_timing[0];
+ i2c->ac_timing.inter_clk_div = ac_timing[1];
+ i2c->ac_timing.scl_hl_ratio = ac_timing[2];
+ i2c->ac_timing.hs_scl_hl_ratio = ac_timing[3];
+ i2c->ac_timing.scl_mis_comp = ac_timing[4];
+ i2c->ac_timing.sta_stop = ac_timing[5];
+ i2c->ac_timing.hs_sta_stop = ac_timing[6];
+ i2c->ac_timing.sda_timing = ac_timing[7];
+ }
+ }
+
i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
i2c->use_push_pull =
of_property_read_bool(np, "mediatek,use-push-pull");
@@ -951,7 +1021,7 @@ static int mtk_i2c_probe(struct platform_device *pdev)
return -EINVAL;

if (i2c->dev_comp->timing_adjust)
- i2c->clk_src_div *= I2C_DEFAULT_CLK_DIV;
+ i2c->clk_src_div *= i2c->ac_timing.inter_clk_div;

if (i2c->have_pmic && !i2c->dev_comp->pmic_i2c)
return -EINVAL;
--
1.7.9.5
\
 
 \ /
  Last update: 2019-06-11 10:14    [W:0.084 / U:2.908 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site