[PATCH V3 3/3] i2c: mediatek: Isolate speed setting via dts for special devices

kewei.xu
2021-06-21T10:46:50Z

In the commit be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust
support"), the I2C timing calculation has been revised to support
ac-timing adjustment, however that will break on some I2C components.
As a result we want to introduce a new setting "default-adjust-timing"
so those components can choose to use the old (default) timing algorithm.

Fixes: be5ce0e97cc7 ("i2c: mediatek: Add i2c ac-timing adjust support")
Signed-off-by: Kewei Xu <kewei.xu@mediatek.com>
---
drivers/i2c/busses/i2c-mt65xx.c | 75 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 71 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index fe3cea7..486076f 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -65,6 +65,7 @@
#define I2C_DMA_HARD_RST 0x0002
#define I2C_DMA_HANDSHAKE_RST 0x0004

+#define I2C_DEFAULT_CLK_DIV 5
#define MAX_SAMPLE_CNT_DIV 8
#define MAX_STEP_CNT_DIV 64
#define MAX_CLOCK_DIV 256
@@ -249,6 +250,7 @@ struct mtk_i2c {
struct clk *clk_arb; /* Arbitrator clock for i2c */
bool have_pmic; /* can use i2c pins from PMIC */
bool use_push_pull; /* IO config push-pull mode */
+ bool default_timing_adjust; /* no timing adjust mode */

u16 irq_stat; /* interrupt status */
unsigned int clk_src_div;
@@ -526,7 +528,11 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
else
ext_conf_val = I2C_FS_START_CON;

- if (i2c->dev_comp->timing_adjust) {
+ if (i2c->default_timing_adjust) {
+ if (i2c->dev_comp->timing_adjust)
+ mtk_i2c_writew(i2c, I2C_DEFAULT_CLK_DIV - 1,
+ OFFSET_CLOCK_DIV);
+ } else if (i2c->dev_comp->timing_adjust) {
ext_conf_val = i2c->ac_timing.ext;
mtk_i2c_writew(i2c, i2c->ac_timing.inter_clk_div,
OFFSET_CLOCK_DIV);
@@ -609,7 +615,7 @@ static int mtk_i2c_check_ac_timing(struct mtk_i2c *i2c,
unsigned int sample_ns = div_u64(1000000000ULL * (sample_cnt + 1),
clk_src);

- if (!i2c->dev_comp->timing_adjust)
+ if (i2c->default_timing_adjust || !i2c->dev_comp->timing_adjust)
return 0;

if (i2c->dev_comp->ltiming_adjust)
@@ -769,7 +775,63 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src,
return 0;
}

-static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
+static int mtk_i2c_set_speed_default_timing(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;
+
+ if (i2c->dev_comp->timing_adjust)
+ i2c->clk_src_div *= I2C_DEFAULT_CLK_DIV;
+
+ clk_src = parent_clk / i2c->clk_src_div;
+ target_speed = i2c->speed_hz;
+
+ if (target_speed > I2C_MAX_FAST_MODE_PLUS_FREQ) {
+ /* Set master code speed register */
+ ret = mtk_i2c_calculate_speed(i2c, clk_src, I2C_MAX_FAST_MODE_FREQ,
+ &l_step_cnt, &l_sample_cnt);
+ if (ret < 0)
+ return ret;
+
+ 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,
+ &step_cnt, &sample_cnt);
+ if (ret < 0)
+ return ret;
+
+ i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
+ (sample_cnt << 12) | (step_cnt << 8);
+
+ if (i2c->dev_comp->ltiming_adjust)
+ 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);
+ if (ret < 0)
+ return ret;
+
+ i2c->timing_reg = (sample_cnt << 8) | step_cnt;
+
+ /* Disable the high speed transaction */
+ i2c->high_speed_reg = I2C_TIME_CLR_VALUE;
+
+ if (i2c->dev_comp->ltiming_adjust)
+ i2c->ltiming_reg = (sample_cnt << 6) | step_cnt;
+ }
+
+ return 0;
+}
+
+static int mtk_i2c_set_speed_adjust_timing(struct mtk_i2c *i2c,
+ unsigned int parent_clk)
{
unsigned int clk_src;
unsigned int step_cnt;
@@ -1293,6 +1355,8 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
i2c->use_push_pull =
of_property_read_bool(np, "mediatek,use-push-pull");
+ i2c->default_timing_adjust =
+ of_property_read_bool(np, "mediatek,default-timing-adjust");

i2c_parse_fw_timings(i2c->dev, &i2c->timing_info, true);

@@ -1372,7 +1436,10 @@ static int mtk_i2c_probe(struct platform_device *pdev)

strlcpy(i2c->adap.name, I2C_DRV_NAME, sizeof(i2c->adap.name));

- ret = mtk_i2c_set_speed(i2c, clk_get_rate(clk));
+ if (i2c->default_timing_adjust)
+ ret = mtk_i2c_set_speed_default_timing(i2c, clk_get_rate(clk));
+ else
+ ret = mtk_i2c_set_speed_adjust_timing(i2c, clk_get_rate(clk));
if (ret) {
dev_err(&pdev->dev, "Failed to set the speed.\n");
return -EINVAL;