Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 75 insertions, 5 deletions

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index 2b0b9cdffa..385ef9d9e4 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -194,6 +194,11 @@ struct exynos5_i2c {
 	 */
 	int			trans_done;
 
+	/*
+	 * Called from atomic context, don't use interrupts.
+	 */
+	unsigned int		atomic;
+
 	/* Controller operating frequency */
 	unsigned int		op_clock;
 
@@ -265,7 +270,7 @@ static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c)
  * exynos5_i2c_set_timing: updates the registers with appropriate
  * timing values calculated
  *
- * Timing values for operation are calculated against either 100kHz
+ * Timing values for operation are calculated against 100kHz, 400kHz
  * or 1MHz controller operating frequency.
  *
  * Returns 0 on success, -EINVAL if the cycle length cannot
@@ -328,6 +333,23 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
 	 *
 	 * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510
 	 *
+	 * To split SCL clock into low, high periods appropriately, one
+	 * proportion factor for each I2C mode is used, which is calculated
+	 * using this formula.
+	 * ```
+	 * ((t_low_min + (scl_clock - t_low_min - t_high_min) / 2) / scl_clock)
+	 * ```
+	 * where:
+	 * t_low_min is the minimal value of low period of the SCL clock in us;
+	 * t_high_min is the minimal value of high period of the SCL clock in us;
+	 * scl_clock is converted from SCL clock frequency into us.
+	 *
+	 * Below are the proportion factors for these I2C modes:
+	 *                t_low_min, t_high_min, scl_clock, proportion
+	 * Standard Mode:     4.7us,      4.0us,      10us,      0.535
+	 * Fast Mode:         1.3us,      0.6us,     2.5us,       0.64
+	 * Fast-Plus Mode:    0.5us,     0.26us,       1us,       0.62
+	 *
 	 */
 	t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7;
 	temp = clkin / op_clk - 8 - t_ftl_cycle;
@@ -341,8 +363,19 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
 		return -EINVAL;
 	}
 
-	t_scl_l = clk_cycle / 2;
-	t_scl_h = clk_cycle / 2;
+	/*
+	 * Scale clk_cycle to get t_scl_l using the proption factors for individual I2C modes.
+	 */
+	if (op_clk <= I2C_MAX_STANDARD_MODE_FREQ)
+		t_scl_l = clk_cycle * 535 / 1000;
+	else if (op_clk <= I2C_MAX_FAST_MODE_FREQ)
+		t_scl_l = clk_cycle * 64 / 100;
+	else
+		t_scl_l = clk_cycle * 62 / 100;
+
+	if (t_scl_l > 0xFF)
+		t_scl_l = 0xFF;
+	t_scl_h = clk_cycle - t_scl_l;
 	t_start_su = t_scl_l;
 	t_start_hd = t_scl_l;
 	t_stop_su = t_scl_l;
@@ -711,6 +744,22 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
 	spin_unlock_irqrestore(&i2c->lock, flags);
 }
 
+static bool exynos5_i2c_poll_irqs_timeout(struct exynos5_i2c *i2c,
+					  unsigned long timeout)
+{
+	unsigned long time_left = jiffies + timeout;
+
+	while (time_before(jiffies, time_left) &&
+	       !((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) ||
+	         (i2c->state < 0))) {
+		while (readl(i2c->regs + HSI2C_INT_ENABLE) &
+		       readl(i2c->regs + HSI2C_INT_STATUS))
+			exynos5_i2c_irq(i2c->irq, i2c);
+		usleep_range(100, 200);
+	}
+	return time_before(jiffies, time_left);
+}
+
 static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c,
 			      struct i2c_msg *msgs, int stop)
 {
@@ -725,8 +774,13 @@ static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c,
 
 	exynos5_i2c_message_start(i2c, stop);
 
-	timeout = wait_for_completion_timeout(&i2c->msg_complete,
-					      EXYNOS5_I2C_TIMEOUT);
+	if (!i2c->atomic)
+		timeout = wait_for_completion_timeout(&i2c->msg_complete,
+						      EXYNOS5_I2C_TIMEOUT);
+	else
+		timeout = exynos5_i2c_poll_irqs_timeout(i2c,
+							EXYNOS5_I2C_TIMEOUT);
+
 	if (timeout == 0)
 		ret = -ETIMEDOUT;
 	else
@@ -777,6 +831,21 @@ err_pclk:
 	return ret ?: num;
 }
 
+static int exynos5_i2c_xfer_atomic(struct i2c_adapter *adap,
+				   struct i2c_msg *msgs, int num)
+{
+	struct exynos5_i2c *i2c = adap->algo_data;
+	int ret;
+
+	disable_irq(i2c->irq);
+	i2c->atomic = true;
+	ret = exynos5_i2c_xfer(adap, msgs, num);
+	i2c->atomic = false;
+	enable_irq(i2c->irq);
+
+	return ret;
+}
+
 static u32 exynos5_i2c_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
@@ -784,6 +853,7 @@ static u32 exynos5_i2c_func(struct i2c_adapter *adap)
 
 static const struct i2c_algorithm exynos5_i2c_algorithm = {
 	.master_xfer		= exynos5_i2c_xfer,
+	.master_xfer_atomic	= exynos5_i2c_xfer_atomic,
 	.functionality		= exynos5_i2c_func,
 };