[PATCH] i2c: rk3x: Add two new features for rk3399
David Wu
wdc at rock-chips.com
Wed Dec 9 01:11:46 PST 2015
1. support highspeed.
2. check i2c bus idle status.
Change-Id: I9c22e752af621c0f8dbcbd399c86b34fd810ec38
Signed-off-by: David Wu <wdc at rock-chips.com>
---
drivers/i2c/busses/i2c-rk3x.c | 336 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 320 insertions(+), 16 deletions(-)
mode change 100644 => 100755 drivers/i2c/busses/i2c-rk3x.c
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
old mode 100644
new mode 100755
index c1935eb..b1aa702
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -25,6 +25,7 @@
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/math64.h>
+#include <linux/delay.h>
/* Register Map */
@@ -37,6 +38,7 @@
#define REG_IEN 0x18 /* interrupt enable */
#define REG_IPD 0x1c /* interrupt pending */
#define REG_FCNT 0x20 /* finished count */
+#define I2C_ST 0x220 /* i2c pin status */
/* Data buffer offsets */
#define TXBUFFER_BASE 0x100
@@ -58,6 +60,12 @@ enum {
#define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */
#define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */
+#define VERSION_MASK 0xffff0000
+#define VERSION_SHIFT 16
+
+#define RK3X_I2C_V0 0x0
+#define RK3X_I2C_V1 0x1
+
/* REG_MRXADDR bits */
#define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */
@@ -71,6 +79,13 @@ enum {
#define REG_INT_NAKRCV BIT(6) /* NACK received */
#define REG_INT_ALL 0x7f
+enum {
+ I2C_IDLE = 0,
+ I2C_SDA_LOW,
+ I2C_SCL_LOW,
+ BOTH_LOW,
+};
+
/* Constants */
#define WAIT_TIMEOUT 1000 /* ms */
#define DEFAULT_SCL_RATE (100 * 1000) /* Hz */
@@ -90,10 +105,23 @@ struct rk3x_i2c_soc_data {
int grf_offset;
};
+struct rk3x_i2c_ops {
+ int (*check_idle)(void __iomem *);
+ int (*calc_divs)(unsigned long,
+ unsigned long,
+ unsigned long,
+ unsigned long,
+ unsigned long,
+ unsigned long *,
+ unsigned long *,
+ unsigned int *);
+};
+
struct rk3x_i2c {
struct i2c_adapter adap;
struct device *dev;
struct rk3x_i2c_soc_data *soc_data;
+ struct rk3x_i2c_ops ops;
/* Hardware resources */
void __iomem *regs;
@@ -116,6 +144,7 @@ struct rk3x_i2c {
u8 addr;
unsigned int mode;
bool is_last_msg;
+ unsigned int time_con;
/* I2C state machine */
enum rk3x_i2c_state state;
@@ -151,7 +180,8 @@ static void rk3x_i2c_start(struct rk3x_i2c *i2c)
i2c_writel(i2c, REG_INT_START, REG_IEN);
/* enable adapter with correct mode, send START condition */
- val = REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START;
+ val = i2c->time_con | REG_CON_EN | REG_CON_MOD(i2c->mode)
+ | REG_CON_START;
/* if we want to react to NACK, set ACTACK bit */
if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
@@ -443,16 +473,19 @@ out:
* @sda_fall_ns: How many ns it takes for SDA to fall.
* @div_low: Divider output for low
* @div_high: Divider output for high
+ * @con: version0 is not used
*
* Returns: 0 on success, -EINVAL if the goal SCL rate is too slow. In that case
* a best-effort divider value is returned in divs. If the target rate is
* too high, we silently use the highest possible rate.
*/
-static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate,
- unsigned long scl_rise_ns,
- unsigned long scl_fall_ns,
- unsigned long sda_fall_ns,
- unsigned long *div_low, unsigned long *div_high)
+static int rk3x_i2c_v0_calc_divs(unsigned long clk_rate, unsigned long scl_rate,
+ unsigned long scl_rise_ns,
+ unsigned long scl_fall_ns,
+ unsigned long sda_fall_ns,
+ unsigned long *div_low,
+ unsigned long *div_high,
+ unsigned int *con)
{
unsigned long spec_min_low_ns, spec_min_high_ns;
unsigned long spec_setup_start, spec_max_data_hold_ns;
@@ -614,19 +647,244 @@ static int rk3x_i2c_calc_divs(unsigned long clk_rate, unsigned long scl_rate,
return ret;
}
+/**
+ * Calculate divider values for desired SCL frequency
+ *
+ * @clk_rate: I2C input clock rate
+ * @scl_rate: Desired SCL rate
+ * @scl_rise_ns: How many ns it takes for SCL to rise.
+ * @scl_fall_ns: How many ns it takes for SCL to fall.
+ * @sda_fall_ns: How many ns it takes for SDA to fall.
+ * @div_low: Divider output for low
+ * @div_high: Divider output for high
+ * @con: SDA update point config used to adjust setup/hold time,
+ * start setup config for setup_start and hold_start time,
+ * stop_setup config for setup_stop time.
+ *
+ * Returns: 0 on success, -EINVAL if the goal SCL rate is too slow. In that case
+ * a best-effort divider value is returned in divs. If the target rate is
+ * too high, we silently use the highest possible rate.
+
+ * l = divl + 1;
+ * h = divh + 1;
+ * s = data_upd_st + 1;
+ * u = start_setup_cnt + 1;
+ * p = stop_setup_cnt + 1;
+ * T:Tclk_i2c
+
+ * tHigh = 8 * h * T;
+ * tLow = 8 * l * T;
+
+ * tHD;sda = (l * s + 1) * T;
+ * tSU;sda = ((8 - l) * s + 1) * T;
+ * tI2C = 8 * (l + h) * T;
+
+ * tSU;sta = (8h * u + 1) * T;
+ * tHD;sta = [8h * (u + 1) - 1]* T;
+ * tSU;sto =(8h * p + 1) * T;
+ */
+static int rk3x_i2c_v1_calc_divs(unsigned long clk_rate, unsigned long scl_rate,
+ unsigned long scl_rise_ns,
+ unsigned long scl_fall_ns,
+ unsigned long sda_fall_ns,
+ unsigned long *div_low,
+ unsigned long *div_high,
+ unsigned int *con)
+{
+ unsigned long spec_min_low_ns, spec_min_high_ns;
+ unsigned long spec_min_setup_start, spec_min_hold_start;
+ unsigned long spec_min_data_setup, spec_max_data_hold_ns;
+ unsigned long spec_min_stop_setup;
+
+ unsigned long min_low_ns, min_high_ns, min_total_ns;
+ unsigned long min_setup_start_ns, min_hold_start_ns;
+ unsigned long min_stop_setup_ns, max_hold_data_ns, min_setup_data_ns;
+
+ unsigned long clk_rate_khz, scl_rate_khz;
+
+ unsigned long min_low_div, min_high_div;
+
+ unsigned long min_div_for_hold, min_total_div;
+ unsigned long extra_div, extra_low_div;
+ unsigned long start_setup_cnt, stop_setup_cnt, data_upd_st;
+
+ int ret = 0;
+
+ if (WARN_ON(scl_rate > 3400000))
+ scl_rate = 3400000;
+
+ if (WARN_ON(scl_rate < 100000))
+ scl_rate = 100000;
+
+ if (scl_rate <= 100000) {
+ spec_min_low_ns = 4700;
+ spec_min_high_ns = 4000;
+
+ spec_min_setup_start = 4700;
+ spec_min_hold_start = 4000;
+
+ spec_max_data_hold_ns = 3450;
+ spec_min_data_setup = 250;
+ spec_min_stop_setup = 4000;
+
+ start_setup_cnt = 0;
+ stop_setup_cnt = 0;
+ } else if (scl_rate <= 400000) {
+ spec_min_setup_start = 600;
+ spec_min_hold_start = 600;
+
+ spec_min_low_ns = 1300;
+ spec_min_high_ns = 600;
+
+ spec_min_data_setup = 100;
+ spec_max_data_hold_ns = 900;
+ spec_min_stop_setup = 600;
+
+ start_setup_cnt = 0;
+ stop_setup_cnt = 0;
+ } else if (scl_rate <= 1700000) {
+ spec_min_low_ns = 320;
+ spec_min_high_ns = 120;
+
+ spec_min_setup_start = 160;
+ spec_min_hold_start = 160;
+
+ spec_max_data_hold_ns = 150;
+ spec_min_data_setup = 10;
+ spec_min_stop_setup = 160;
+
+ start_setup_cnt = 1;
+ stop_setup_cnt = 1;
+ } else {
+ spec_min_low_ns = 160;
+ spec_min_high_ns = 60;
+
+ spec_min_setup_start = 160;
+ spec_min_hold_start = 160;
+
+ spec_min_data_setup = 10;
+ spec_max_data_hold_ns = 70;
+ spec_min_stop_setup = 160;
+
+ start_setup_cnt = 2;
+ stop_setup_cnt = 2;
+ }
+
+ clk_rate_khz = DIV_ROUND_UP(clk_rate, 1000);
+ scl_rate_khz = scl_rate / 1000;
+ min_total_div = DIV_ROUND_UP(clk_rate_khz, scl_rate_khz * 8);
+
+ /*tHigh = 8 * h *T;*/
+ min_high_ns = scl_rise_ns + spec_min_high_ns;
+ min_high_div = DIV_ROUND_UP(clk_rate_khz * min_high_ns, 8 * 1000000);
+
+ /*tSU;sta = (u*8*h + 4)*T + T;*/
+ min_setup_start_ns = scl_rise_ns + spec_min_setup_start;
+ min_high_div = max(min_high_div,
+ DIV_ROUND_UP(clk_rate_khz * min_setup_start_ns
+ - 1000000, 8 * 1000000 * (1 + start_setup_cnt)));
+
+ /*tHD;sta = (u + 1) * 8h * T - T;*/
+ min_hold_start_ns = scl_rise_ns + spec_min_hold_start;
+ min_high_div = max(min_high_div,
+ DIV_ROUND_UP(clk_rate_khz * min_hold_start_ns
+ + 1000000, 8 * 1000000 * (2 + start_setup_cnt)));
+
+ /*tSU;sto = (p*8*h + 4)*T + T;*/
+ min_stop_setup_ns = scl_rise_ns + spec_min_stop_setup;
+ min_high_div = max(min_high_div,
+ DIV_ROUND_UP(clk_rate_khz * min_stop_setup_ns
+ - 1000000, 8 * 1000000 * (1 + stop_setup_cnt)));
+
+ min_low_ns = scl_fall_ns + spec_min_low_ns;
+
+ /* These are the min dividers needed for min hold times. */
+ min_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns, 8 * 1000000);
+
+ min_div_for_hold = (min_low_div + min_high_div);
+ min_total_ns = min_low_ns + min_high_ns;
+
+ /*
+ * This is the maximum divider so we don't go over the maximum.
+ * We don't round up here (we round down) since this is a maximum.
+ */
+ if (min_div_for_hold >= min_total_div) {
+ /*
+ * Time needed to meet hold requirements is important.
+ * Just use that.
+ */
+ *div_low = min_low_div;
+ *div_high = min_high_div;
+ } else {
+ /*
+ * We've got to distribute some time among the low and high
+ * so we don't run too fast.
+ */
+ extra_div = min_total_div - min_div_for_hold;
+ extra_low_div = DIV_ROUND_UP(min_low_div * extra_div,
+ min_div_for_hold);
+
+ *div_low = min_low_div + extra_low_div;
+ *div_high = min_high_div + (extra_div - extra_low_div);
+ }
+
+ /*
+ * tHD;sda = (l * s + 1) * T;
+ * tSU;sda = ((8 - l) * s + 1) * T;
+ */
+ for (data_upd_st = 2; data_upd_st >= 0; data_upd_st--) {
+ max_hold_data_ns = DIV_ROUND_UP(((data_upd_st + 1)
+ * (*div_low) + 1) * 1000000,
+ clk_rate_khz);
+ min_setup_data_ns = DIV_ROUND_UP(((9 - data_upd_st)
+ * (*div_low) + 1) * 1000000,
+ clk_rate_khz);
+ if ((max_hold_data_ns < spec_max_data_hold_ns) &&
+ (min_setup_data_ns > spec_min_data_setup))
+ break;
+ }
+
+ /*
+ * Adjust to the fact that the hardware has an implicit "+1".
+ * NOTE: Above calculations always produce div_low > 0 and div_high > 0.
+ */
+ *div_low = *div_low - 1;
+ *div_high = *div_high - 1;
+
+ /* Maximum divider supported by hw is 0xffff */
+ if (*div_low > 0xffff) {
+ *div_low = 0xffff;
+ ret = -EINVAL;
+ }
+
+ if (*div_high > 0xffff) {
+ *div_high = 0xffff;
+ ret = -EINVAL;
+ }
+
+ *con = *con & 0x00ff;
+ *con |= data_upd_st << 8;
+ *con |= start_setup_cnt << 12;
+ *con |= stop_setup_cnt << 14;
+
+ return ret;
+}
+
static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
{
+ unsigned int con = 0;
unsigned long div_low, div_high;
u64 t_low_ns, t_high_ns;
int ret;
- ret = rk3x_i2c_calc_divs(clk_rate, i2c->scl_frequency, i2c->scl_rise_ns,
+ ret = i2c->ops.calc_divs(clk_rate, i2c->scl_frequency, i2c->scl_rise_ns,
i2c->scl_fall_ns, i2c->sda_fall_ns,
- &div_low, &div_high);
+ &div_low, &div_high, &con);
WARN_ONCE(ret != 0, "Could not reach SCL freq %u", i2c->scl_frequency);
clk_enable(i2c->clk);
i2c_writel(i2c, (div_high << 16) | (div_low & 0xffff), REG_CLKDIV);
+ i2c->time_con = con;
clk_disable(i2c->clk);
t_low_ns = div_u64(((u64)div_low + 1) * 8 * 1000000000, clk_rate);
@@ -661,13 +919,14 @@ static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
struct clk_notifier_data *ndata = data;
struct rk3x_i2c *i2c = container_of(nb, struct rk3x_i2c, clk_rate_nb);
unsigned long div_low, div_high;
+ unsigned int con = 0;
switch (event) {
case PRE_RATE_CHANGE:
- if (rk3x_i2c_calc_divs(ndata->new_rate, i2c->scl_frequency,
+ if (i2c->ops.calc_divs(ndata->new_rate, i2c->scl_frequency,
i2c->scl_rise_ns, i2c->scl_fall_ns,
i2c->sda_fall_ns,
- &div_low, &div_high) != 0)
+ &div_low, &div_high, &con) != 0)
return NOTIFY_STOP;
/* scale up */
@@ -690,6 +949,11 @@ static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
}
}
+static int rockchip_i2c_v1_check_idle(void __iomem *regs)
+{
+ return readl(regs + I2C_ST) & 0x03;
+}
+
/**
* Setup I2C registers for an I2C operation specified by msgs, num.
*
@@ -777,6 +1041,7 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap,
{
struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data;
unsigned long timeout, flags;
+ int state, retry = 10;
int ret = 0;
int i;
@@ -784,6 +1049,21 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap,
clk_enable(i2c->clk);
+ if (i2c->ops.check_idle) {
+ while (retry) {
+ state = i2c->ops.check_idle(i2c);
+ if (state == I2C_IDLE)
+ break;
+ mdelay(10);
+ retry--;
+ }
+ if (retry == 0) {
+ dev_err(i2c->dev, "i2c is not in idle(state = %d)\n",
+ state);
+ return -EIO;
+ }
+ }
+
i2c->is_last_msg = false;
/*
@@ -816,7 +1096,8 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap,
/* Force a STOP condition without interrupt */
i2c_writel(i2c, 0, REG_IEN);
- i2c_writel(i2c, REG_CON_EN | REG_CON_STOP, REG_CON);
+ i2c_writel(i2c, i2c->time_con | REG_CON_EN |
+ REG_CON_STOP, REG_CON);
i2c->state = STATE_IDLE;
@@ -871,6 +1152,7 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
u32 value;
int irq;
unsigned long clk_rate;
+ unsigned int version;
i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
if (!i2c)
@@ -901,15 +1183,29 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
&i2c->scl_rise_ns)) {
if (i2c->scl_frequency <= 100000)
i2c->scl_rise_ns = 1000;
- else
+ else if (i2c->scl_frequency <= 400000)
i2c->scl_rise_ns = 300;
+ else if (i2c->scl_frequency <= 1700000)
+ i2c->scl_rise_ns = 80;
+ else
+ i2c->scl_rise_ns = 40;
}
if (of_property_read_u32(pdev->dev.of_node, "i2c-scl-falling-time-ns",
- &i2c->scl_fall_ns))
- i2c->scl_fall_ns = 300;
+ &i2c->scl_fall_ns)) {
+ if (i2c->scl_frequency <= 400000)
+ i2c->scl_fall_ns = 300;
+ else if (i2c->scl_frequency <= 1700000)
+ i2c->scl_fall_ns = 80;
+ else
+ i2c->scl_fall_ns = 40;
+ }
if (of_property_read_u32(pdev->dev.of_node, "i2c-sda-falling-time-ns",
- &i2c->scl_fall_ns))
- i2c->sda_fall_ns = i2c->scl_fall_ns;
+ &i2c->scl_fall_ns)) {
+ if (i2c->scl_frequency <= 400000)
+ i2c->sda_fall_ns = i2c->scl_fall_ns;
+ else
+ i2c->sda_fall_ns = 2 * i2c->scl_fall_ns;
+ }
strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
i2c->adap.owner = THIS_MODULE;
@@ -983,6 +1279,14 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, i2c);
+ version = (readl(i2c->regs + REG_CON) & VERSION_MASK) >> VERSION_SHIFT;
+ if (version == RK3X_I2C_V1) {
+ i2c->ops.calc_divs = rk3x_i2c_v1_calc_divs;
+ i2c->ops.check_idle = rockchip_i2c_v1_check_idle;
+ } else {
+ i2c->ops.calc_divs = rk3x_i2c_v0_calc_divs;
+ }
+
ret = clk_prepare(i2c->clk);
if (ret < 0) {
dev_err(&pdev->dev, "Could not prepare clock\n");
--
1.9.1
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