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133 lines
4.1 KiB
Diff
133 lines
4.1 KiB
Diff
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From f606aab3f1a49d723d66e14e545f6ca45005bda6 Mon Sep 17 00:00:00 2001
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From: Kewei Xu <kewei.xu@mediatek.com>
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Date: Thu, 17 Feb 2022 20:22:43 +0800
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Subject: [PATCH 04/16] i2c: mediatek: modify bus speed calculation formula
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When clock-div is 0 or greater than 1, the bus speed
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calculated by the old speed calculation formula will be
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larger than the target speed. So we update the formula.
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Signed-off-by: Kewei Xu <kewei.xu@mediatek.com>
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Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
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Reviewed-by: Qii Wang <qii.wang@mediatek.com>
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Signed-off-by: Wolfram Sang <wsa@kernel.org>
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---
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drivers/i2c/busses/i2c-mt65xx.c | 51 ++++++++++++++++++++++++++-------
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1 file changed, 41 insertions(+), 10 deletions(-)
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--- a/drivers/i2c/busses/i2c-mt65xx.c
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+++ b/drivers/i2c/busses/i2c-mt65xx.c
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@@ -67,11 +67,12 @@
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#define MAX_SAMPLE_CNT_DIV 8
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#define MAX_STEP_CNT_DIV 64
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-#define MAX_CLOCK_DIV 256
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+#define MAX_CLOCK_DIV_8BITS 256
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+#define MAX_CLOCK_DIV_5BITS 32
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#define MAX_HS_STEP_CNT_DIV 8
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-#define I2C_STANDARD_MODE_BUFFER (1000 / 2)
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-#define I2C_FAST_MODE_BUFFER (300 / 2)
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-#define I2C_FAST_MODE_PLUS_BUFFER (20 / 2)
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+#define I2C_STANDARD_MODE_BUFFER (1000 / 3)
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+#define I2C_FAST_MODE_BUFFER (300 / 3)
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+#define I2C_FAST_MODE_PLUS_BUFFER (20 / 3)
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#define I2C_CONTROL_RS (0x1 << 1)
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#define I2C_CONTROL_DMA_EN (0x1 << 2)
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@@ -604,6 +605,31 @@ static int mtk_i2c_max_step_cnt(unsigned
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return MAX_STEP_CNT_DIV;
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}
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+static int mtk_i2c_get_clk_div_restri(struct mtk_i2c *i2c,
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+ unsigned int sample_cnt)
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+{
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+ int clk_div_restri = 0;
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+
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+ if (i2c->dev_comp->ltiming_adjust == 0)
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+ return 0;
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+
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+ if (sample_cnt == 1) {
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+ if (i2c->ac_timing.inter_clk_div == 0)
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+ clk_div_restri = 0;
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+ else
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+ clk_div_restri = 1;
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+ } else {
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+ if (i2c->ac_timing.inter_clk_div == 0)
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+ clk_div_restri = -1;
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+ else if (i2c->ac_timing.inter_clk_div == 1)
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+ clk_div_restri = 0;
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+ else
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+ clk_div_restri = 1;
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+ }
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+
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+ return clk_div_restri;
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+}
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+
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/*
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* Check and Calculate i2c ac-timing
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*
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@@ -732,6 +758,7 @@ static int mtk_i2c_calculate_speed(struc
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unsigned int best_mul;
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unsigned int cnt_mul;
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int ret = -EINVAL;
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+ int clk_div_restri = 0;
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if (target_speed > I2C_MAX_HIGH_SPEED_MODE_FREQ)
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target_speed = I2C_MAX_HIGH_SPEED_MODE_FREQ;
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@@ -749,7 +776,8 @@ static int mtk_i2c_calculate_speed(struc
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* optimizing for sample_cnt * step_cnt being minimal
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*/
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for (sample_cnt = 1; sample_cnt <= MAX_SAMPLE_CNT_DIV; sample_cnt++) {
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- step_cnt = DIV_ROUND_UP(opt_div, sample_cnt);
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+ clk_div_restri = mtk_i2c_get_clk_div_restri(i2c, sample_cnt);
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+ step_cnt = DIV_ROUND_UP(opt_div + clk_div_restri, sample_cnt);
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cnt_mul = step_cnt * sample_cnt;
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if (step_cnt > max_step_cnt)
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continue;
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@@ -763,7 +791,7 @@ static int mtk_i2c_calculate_speed(struc
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best_mul = cnt_mul;
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base_sample_cnt = sample_cnt;
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base_step_cnt = step_cnt;
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- if (best_mul == opt_div)
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+ if (best_mul == (opt_div + clk_div_restri))
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break;
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}
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}
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@@ -774,7 +802,8 @@ static int mtk_i2c_calculate_speed(struc
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sample_cnt = base_sample_cnt;
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step_cnt = base_step_cnt;
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- if ((clk_src / (2 * sample_cnt * step_cnt)) > target_speed) {
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+ if ((clk_src / (2 * (sample_cnt * step_cnt - clk_div_restri))) >
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+ target_speed) {
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/* In this case, hardware can't support such
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* low i2c_bus_freq
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*/
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@@ -803,13 +832,16 @@ static int mtk_i2c_set_speed(struct mtk_
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target_speed = i2c->speed_hz;
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parent_clk /= i2c->clk_src_div;
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- if (i2c->dev_comp->timing_adjust)
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- max_clk_div = MAX_CLOCK_DIV;
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+ if (i2c->dev_comp->timing_adjust && i2c->dev_comp->ltiming_adjust)
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+ max_clk_div = MAX_CLOCK_DIV_5BITS;
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+ else if (i2c->dev_comp->timing_adjust)
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+ max_clk_div = MAX_CLOCK_DIV_8BITS;
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else
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max_clk_div = 1;
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for (clk_div = 1; clk_div <= max_clk_div; clk_div++) {
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clk_src = parent_clk / clk_div;
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+ i2c->ac_timing.inter_clk_div = clk_div - 1;
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if (target_speed > I2C_MAX_FAST_MODE_PLUS_FREQ) {
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/* Set master code speed register */
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@@ -856,7 +888,6 @@ static int mtk_i2c_set_speed(struct mtk_
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break;
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}
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- i2c->ac_timing.inter_clk_div = clk_div - 1;
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return 0;
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}
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