[PATCH 0/3] i2c-xlp9xx: update i2c driver to handle I2C_M_RECV_LEN flag

[PATCH 0/3] i2c-xlp9xx: update i2c driver to handle I2C_M_RECV_LEN flag

[Kamlakant Patel]

This patch set has following changes:
 * Use Linux clk APIs to get input clock frequency for the I2C controller.
 * I2C driver update to handle I2C_M_RECV_LEN and I2C_CLIENT_PEC flags.

Jayachandran C (2):
  ACPI / APD: Add clock frequency for ThunderX2 I2C controller
  i2c: xlp9xx: Get clock frequency with clk API

Kamlakant Patel (1):
  i2c: xlp9xx: Handle I2C_M_RECV_LEN in msg->flags

 drivers/acpi/acpi_apd.c         |  5 +++++
 drivers/i2c/busses/i2c-xlp9xx.c | 44 +++++++++++++++++++++++++++++++++++++----
 2 files changed, 45 insertions(+), 4 deletions(-)

-- 
2.7.4

[PATCH 1/3] ACPI / APD: Add clock frequency for ThunderX2 I2C controller

[Kamlakant Patel]

From: Jayachandran C <jnair@caviumnetworks.com>

Add the input frequency of 125MHz for the ThunderX2 I2C controller block.
The ACPI ID used is "CAV9007".

Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
Signed-off-by: Kamlakant Patel <kamlakant.patel@cavium.com>
---
 drivers/acpi/acpi_apd.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
index 17a1eb1..93acc9b 100644
--- a/drivers/acpi/acpi_apd.c
+++ b/drivers/acpi/acpi_apd.c
@@ -106,6 +106,10 @@ static const struct apd_device_desc vulcan_spi_desc = {
 	.setup = acpi_apd_setup,
 	.fixed_clk_rate = 133000000,
 };
+static const struct apd_device_desc thunderx2_i2c_desc = {
+	.setup = acpi_apd_setup,
+	.fixed_clk_rate = 125000000,
+};
 #endif
 
 #else
@@ -170,6 +174,7 @@ static const struct acpi_device_id acpi_apd_device_ids[] = {
 	{ "APMC0D0F", APD_ADDR(xgene_i2c_desc) },
 	{ "BRCM900D", APD_ADDR(vulcan_spi_desc) },
 	{ "CAV900D",  APD_ADDR(vulcan_spi_desc) },
+	{ "CAV9007",  APD_ADDR(thunderx2_i2c_desc) },
 #endif
 	{ }
 };
-- 
2.7.4

Re: [PATCH 1/3] ACPI / APD: Add clock frequency for ThunderX2 I2C controller

[Mika Westerberg]

(You should CC Rafael when doing changes touching ACPI)

On Wed, Sep 27, 2017 at 08:22:21PM +0530, Kamlakant Patel wrote:
> From: Jayachandran C <jnair@caviumnetworks.com>
> 
> Add the input frequency of 125MHz for the ThunderX2 I2C controller block.
> The ACPI ID used is "CAV9007".
> 
> Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
> Signed-off-by: Kamlakant Patel <kamlakant.patel@cavium.com>

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

> ---
>  drivers/acpi/acpi_apd.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/acpi/acpi_apd.c b/drivers/acpi/acpi_apd.c
> index 17a1eb1..93acc9b 100644
> --- a/drivers/acpi/acpi_apd.c
> +++ b/drivers/acpi/acpi_apd.c
> @@ -106,6 +106,10 @@ static const struct apd_device_desc vulcan_spi_desc = {
>  	.setup = acpi_apd_setup,
>  	.fixed_clk_rate = 133000000,
>  };
> +static const struct apd_device_desc thunderx2_i2c_desc = {
> +	.setup = acpi_apd_setup,
> +	.fixed_clk_rate = 125000000,
> +};
>  #endif
>  
>  #else
> @@ -170,6 +174,7 @@ static const struct acpi_device_id acpi_apd_device_ids[] = {
>  	{ "APMC0D0F", APD_ADDR(xgene_i2c_desc) },
>  	{ "BRCM900D", APD_ADDR(vulcan_spi_desc) },
>  	{ "CAV900D",  APD_ADDR(vulcan_spi_desc) },
> +	{ "CAV9007",  APD_ADDR(thunderx2_i2c_desc) },
>  #endif
>  	{ }
>  };
> -- 
> 2.7.4

[PATCH 2/3] i2c: xlp9xx: Get clock frequency with clk API

[Kamlakant Patel]

From: Jayachandran C <jnair@caviumnetworks.com>

Get the input clock frequency to the controller from the linux clk
API, if it is available. This allows us to pass in the block input
frequency either from ACPI (using APD) or from device tree.

The old hardcoded frequency is used as default for backwards compatibility.

Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
Signed-off-by: Kamlakant Patel <kamlakant.patel@cavium.com>
---
 drivers/i2c/busses/i2c-xlp9xx.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
index 6b106e9..f0bef2d 100644
--- a/drivers/i2c/busses/i2c-xlp9xx.c
+++ b/drivers/i2c/busses/i2c-xlp9xx.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
@@ -84,6 +85,7 @@ struct xlp9xx_i2c_dev {
 	u32 __iomem *base;
 	u32 msg_buf_remaining;
 	u32 msg_len;
+	u32 ip_clk_hz;
 	u32 clk_hz;
 	u32 msg_err;
 	u8 *msg_buf;
@@ -213,7 +215,7 @@ static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
 	 * The controller uses 5 * SCL clock internally.
 	 * So prescale value should be divided by 5.
 	 */
-	prescale = DIV_ROUND_UP(XLP9XX_I2C_IP_CLK_FREQ, priv->clk_hz);
+	prescale = DIV_ROUND_UP(priv->ip_clk_hz, priv->clk_hz);
 	prescale = ((prescale - 8) / 5) - 1;
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_RST);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_EN |
@@ -342,9 +344,19 @@ static const struct i2c_algorithm xlp9xx_i2c_algo = {
 static int xlp9xx_i2c_get_frequency(struct platform_device *pdev,
 				    struct xlp9xx_i2c_dev *priv)
 {
+	struct clk *clk;
 	u32 freq;
 	int err;
 
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		priv->ip_clk_hz = XLP9XX_I2C_IP_CLK_FREQ;
+		dev_dbg(&pdev->dev, "using default input frequency %u\n",
+			priv->ip_clk_hz);
+	} else {
+		priv->ip_clk_hz = clk_get_rate(clk);
+	}
+
 	err = device_property_read_u32(&pdev->dev, "clock-frequency", &freq);
 	if (err) {
 		freq = XLP9XX_I2C_DEFAULT_FREQ;
-- 
2.7.4

Re: [PATCH 2/3] i2c: xlp9xx: Get clock frequency with clk API

[Mika Westerberg]

On Wed, Sep 27, 2017 at 08:22:22PM +0530, Kamlakant Patel wrote:
> From: Jayachandran C <jnair@caviumnetworks.com>
> 
> Get the input clock frequency to the controller from the linux clk
> API, if it is available. This allows us to pass in the block input
> frequency either from ACPI (using APD) or from device tree.
> 
> The old hardcoded frequency is used as default for backwards compatibility.
> 
> Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
> Signed-off-by: Kamlakant Patel <kamlakant.patel@cavium.com>

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

[PATCH 3/3] i2c: xlp9xx: Handle I2C_M_RECV_LEN in msg->flags

[Kamlakant Patel]

The driver needs to handle the flag I2C_M_RECV_LEN during receive to
support SMBus emulation.

Update receive logic to handle the case where the length is received
as the first byte of a transaction.

Also update the code to handle I2C_CLIENT_PEC, which is set when the
client sends a packet error checking code byte.

Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
Signed-off-by: Kamlakant Patel <kamlakant.patel@cavium.com>
---
 drivers/i2c/busses/i2c-xlp9xx.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
index f0bef2d..91c0369 100644
--- a/drivers/i2c/busses/i2c-xlp9xx.c
+++ b/drivers/i2c/busses/i2c-xlp9xx.c
@@ -82,6 +82,8 @@ struct xlp9xx_i2c_dev {
 	struct completion msg_complete;
 	int irq;
 	bool msg_read;
+	bool len_recv;
+	bool client_pec;
 	u32 __iomem *base;
 	u32 msg_buf_remaining;
 	u32 msg_len;
@@ -143,10 +145,25 @@ static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
 static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
 {
 	u32 len, i;
-	u8 *buf = priv->msg_buf;
+	u8 rlen, *buf = priv->msg_buf;
 
 	len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
 				  XLP9XX_I2C_FIFO_WCNT_MASK;
+	if (!len)
+		return;
+	if (priv->len_recv) {
+		/* read length byte */
+		rlen = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
+		*buf++ = rlen;
+		len--;
+		if (priv->client_pec)
+			++rlen;
+		/* update remaining bytes and message length */
+		priv->msg_buf_remaining = rlen;
+		priv->msg_len = rlen + 1;
+		priv->len_recv = false;
+	}
+
 	len = min(priv->msg_buf_remaining, len);
 	for (i = 0; i < len; i++, buf++)
 		*buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
@@ -230,7 +247,7 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
 			       int last_msg)
 {
 	unsigned long timeleft;
-	u32 intr_mask, cmd, val;
+	u32 intr_mask, cmd, val, len;
 
 	priv->msg_buf = msg->buf;
 	priv->msg_buf_remaining = priv->msg_len = msg->len;
@@ -263,9 +280,13 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
 	else
 		val &= ~XLP9XX_I2C_CTRL_ADDMODE;
 
+	priv->len_recv = (msg->flags & I2C_M_RECV_LEN);
+	len = priv->len_recv ? XLP9XX_I2C_FIFO_SIZE : msg->len;
+	priv->client_pec = (msg->flags & I2C_CLIENT_PEC);
+
 	/* set data length to be transferred */
 	val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) |
-	      (msg->len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
+	      (len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
 	xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);
 
 	/* fill fifo during tx */
@@ -312,6 +333,9 @@ static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
 		return -ETIMEDOUT;
 	}
 
+	/* update msg->len with actual received length */
+	if (msg->flags & I2C_M_RECV_LEN)
+		msg->len = priv->msg_len;
 	return 0;
 }
 
-- 
2.7.4

Re: [PATCH 3/3] i2c: xlp9xx: Handle I2C_M_RECV_LEN in msg->flags

[Mika Westerberg]

On Wed, Sep 27, 2017 at 08:22:23PM +0530, Kamlakant Patel wrote:
> +	priv->len_recv = (msg->flags & I2C_M_RECV_LEN);

You don't need parens here.

> +	len = priv->len_recv ? XLP9XX_I2C_FIFO_SIZE : msg->len;
> +	priv->client_pec = (msg->flags & I2C_CLIENT_PEC);

Ditto.

Otherwise looks good to me,

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>