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i2c: nomadik: support >=1MHz speed modes

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- BRCR value must go into the BRCR1 field when in high-speed mode.
   It goes into BRCR2 otherwise.

 - Remove fallback to standard mode if priv->sm > I2C_FREQ_MODE_FAST.

 - Set SM properly in probe; previously it only checked STANDARD versus
   FAST. Now we set STANDARD, FAST, FAST_PLUS or HIGH_SPEED.

 - Remove all comment sections saying we only support low-speeds.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Théo Lebrun 2024-10-09 16:01:12 +02:00 committed by Wolfram Sang
parent 16674c8c48
commit 4fb1b640d6
1 changed files with 16 additions and 24 deletions
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40
drivers/i2c/busses/i2c-nomadik.c
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@ -397,7 +397,7 @@ static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *priv, u16 flags)
*/
static void setup_i2c_controller(struct nmk_i2c_dev *priv)
{
u32 brcr1, brcr2;
u32 brcr;
u32 i2c_clk, div;
u32 ns;
u16 slsu;
@ -444,7 +444,7 @@ static void setup_i2c_controller(struct nmk_i2c_dev *priv)
/*
* The spec says, in case of std. mode the divider is
* 2 whereas it is 3 for fast and fastplus mode of
* operation. TODO - high speed support.
* operation.
*/
div = (priv->clk_freq > I2C_MAX_STANDARD_MODE_FREQ) ? 3 : 2;
@ -452,34 +452,23 @@ static void setup_i2c_controller(struct nmk_i2c_dev *priv)
* generate the mask for baud rate counters. The controller
* has two baud rate counters. One is used for High speed
* operation, and the other is for std, fast mode, fast mode
* plus operation. Currently we do not supprt high speed mode
* so set brcr1 to 0.
* plus operation.
*
* BRCR is a clock divider amount. Pick highest value that
* leads to rate strictly below target. Eg when asking for
* 400kHz you want a bus rate <=400kHz (and not >=400kHz).
*/
brcr1 = FIELD_PREP(I2C_BRCR_BRCNT1, 0);
brcr2 = FIELD_PREP(I2C_BRCR_BRCNT2, DIV_ROUND_UP(i2c_clk, priv->clk_freq * div));
brcr = DIV_ROUND_UP(i2c_clk, priv->clk_freq * div);
if (priv->sm == I2C_FREQ_MODE_HIGH_SPEED)
brcr = FIELD_PREP(I2C_BRCR_BRCNT1, brcr);
else
brcr = FIELD_PREP(I2C_BRCR_BRCNT2, brcr);
/* set the baud rate counter register */
writel((brcr1 | brcr2), priv->virtbase + I2C_BRCR);
writel(brcr, priv->virtbase + I2C_BRCR);
/*
* set the speed mode. Currently we support
* only standard and fast mode of operation
* TODO - support for fast mode plus (up to 1Mb/s)
* and high speed (up to 3.4 Mb/s)
*/
if (priv->sm > I2C_FREQ_MODE_FAST) {
dev_err(&priv->adev->dev,
"do not support this mode defaulting to std. mode\n");
brcr2 = FIELD_PREP(I2C_BRCR_BRCNT2,
i2c_clk / (I2C_MAX_STANDARD_MODE_FREQ * 2));
writel((brcr1 | brcr2), priv->virtbase + I2C_BRCR);
writel(FIELD_PREP(I2C_CR_SM, I2C_FREQ_MODE_STANDARD),
priv->virtbase + I2C_CR);
}
/* set the speed mode */
writel(FIELD_PREP(I2C_CR_SM, priv->sm), priv->virtbase + I2C_CR);
/* set the Tx and Rx FIFO threshold */
@ -1020,11 +1009,14 @@ static void nmk_i2c_of_probe(struct device_node *np,
if (of_property_read_u32(np, "clock-frequency", &priv->clk_freq))
priv->clk_freq = I2C_MAX_STANDARD_MODE_FREQ;
/* This driver only supports 'standard' and 'fast' modes of operation. */
if (priv->clk_freq <= I2C_MAX_STANDARD_MODE_FREQ)
priv->sm = I2C_FREQ_MODE_STANDARD;
else
else if (priv->clk_freq <= I2C_MAX_FAST_MODE_FREQ)
priv->sm = I2C_FREQ_MODE_FAST;
else if (priv->clk_freq <= I2C_MAX_FAST_MODE_PLUS_FREQ)
priv->sm = I2C_FREQ_MODE_FAST_PLUS;
else
priv->sm = I2C_FREQ_MODE_HIGH_SPEED;
priv->tft = 1; /* Tx FIFO threshold */
priv->rft = 8; /* Rx FIFO threshold */