Patchwork [v2,2/2] i2c: pxa: enable high speed mode for i2c bus

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Submitter Leilei Shang
Date Aug. 9, 2013, 2:43 a.m.
Message ID <1376016204-31328-1-git-send-email-shangll@marvell.com>
Download mbox | patch
Permalink /patch/265873/
State Not Applicable
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Comments

Leilei Shang - Aug. 9, 2013, 2:43 a.m.
From: Leilei Shang <shangll@marvell.com>

To enter high speed mode, following steps should be done:
1. When running in high speed mode, i2c clock rate is different
from standard mode. Clock rate must be set according to
specification first.
2. When I2C controller sends a master code and wins arbitration,
high speed mode is entered.

If you want to enable high speed mode, the following members of
platform data should be set to proper value:
1. "high_mode" should be set to "1".
2. "master_code" should be set to "8'b 0000_1xxx"(x is 0 or 1).
If no master_code is set, set to default value 0xe.
3. "rate" should be set according to specification.

Signed-off-by: Leilei Shang <shangll@marvell.com>
---
 drivers/i2c/busses/i2c-pxa.c |   68 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/i2c/pxa-i2c.h  |    3 ++
 2 files changed, 70 insertions(+), 1 deletions(-)
James Lebron - Aug. 15, 2013, 10:48 a.m.
Hi Guys

Any comments?

2013/8/9 Leilei Shang <shangll@marvell.com>:
> From: Leilei Shang <shangll@marvell.com>
>
> To enter high speed mode, following steps should be done:
> 1. When running in high speed mode, i2c clock rate is different
> from standard mode. Clock rate must be set according to
> specification first.
> 2. When I2C controller sends a master code and wins arbitration,
> high speed mode is entered.
>
> If you want to enable high speed mode, the following members of
> platform data should be set to proper value:
> 1. "high_mode" should be set to "1".
> 2. "master_code" should be set to "8'b 0000_1xxx"(x is 0 or 1).
> If no master_code is set, set to default value 0xe.
> 3. "rate" should be set according to specification.
>
> Signed-off-by: Leilei Shang <shangll@marvell.com>
> ---
>  drivers/i2c/busses/i2c-pxa.c |   68 +++++++++++++++++++++++++++++++++++++++++-
>  include/linux/i2c/pxa-i2c.h  |    3 ++
>  2 files changed, 70 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index 3a5c477..da7b9ae 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -119,6 +119,8 @@ MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
>  #define ICR_SADIE      (1 << 13)          /* slave address detected int enable */
>  #define ICR_UR         (1 << 14)          /* unit reset */
>  #define ICR_FM         (1 << 15)          /* fast mode */
> +#define ICR_HS         (1 << 16)          /* High Speed mode */
> +#define ICR_GPIOEN     (1 << 19)          /* enable GPIO mode for SCL in HS */
>
>  #define ISR_RWM                (1 << 0)           /* read/write mode */
>  #define ISR_ACKNAK     (1 << 1)           /* ack/nak status */
> @@ -164,6 +166,10 @@ struct pxa_i2c {
>         int                     irq;
>         unsigned int            use_pio :1;
>         unsigned int            fast_mode :1;
> +       unsigned int            high_mode:1;
> +       unsigned char           master_code;
> +       unsigned long           rate;
> +       bool                    highmode_enter;
>  };
>
>  #define _IBMR(i2c)     ((i2c)->reg_ibmr)
> @@ -468,6 +474,7 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c)
>
>         /* set control register values */
>         writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
> +       writel(readl(_ICR(i2c)) | (i2c->high_mode ? ICR_HS : 0), _ICR(i2c));
>
>  #ifdef CONFIG_I2C_PXA_SLAVE
>         dev_info(&i2c->adap.dev, "Enabling slave mode\n");
> @@ -689,6 +696,34 @@ static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
>         return 0;
>  }
>
> +/*
> + * PXA I2C send master code
> + * 1. Load master code to IDBR and send it.
> + *    Note for HS mode, set ICR [GPIOEN].
> + * 2. Wait until win arbitration.
> + */
> +static int i2c_pxa_send_mastercode(struct pxa_i2c *i2c)
> +{
> +       u32 icr;
> +       long timeout;
> +
> +       spin_lock_irq(&i2c->lock);
> +       i2c->highmode_enter = true;
> +       writel(i2c->master_code, _IDBR(i2c));
> +
> +       icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
> +       icr |= ICR_GPIOEN | ICR_START | ICR_TB | ICR_ITEIE;
> +       writel(icr, _ICR(i2c));
> +
> +       spin_unlock_irq(&i2c->lock);
> +       timeout = wait_event_timeout(i2c->wait,
> +                       i2c->highmode_enter == false, HZ * 1);
> +
> +       i2c->highmode_enter = false;
> +
> +       return (timeout == 0) ? I2C_RETRY : 0;
> +}
> +
>  static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
>                                struct i2c_msg *msg, int num)
>  {
> @@ -752,6 +787,14 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
>                 goto out;
>         }
>
> +       if (i2c->high_mode) {
> +               ret = i2c_pxa_send_mastercode(i2c);
> +               if (ret) {
> +                       dev_err(&i2c->adap.dev, "i2c_pxa_send_mastercode timeout\n");
> +                       goto out;
> +                       }
> +       }
> +
>         spin_lock_irq(&i2c->lock);
>
>         i2c->msg = msg;
> @@ -999,11 +1042,14 @@ static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
>                         i2c_pxa_slave_txempty(i2c, isr);
>                 if (isr & ISR_IRF)
>                         i2c_pxa_slave_rxfull(i2c, isr);
> -       } else if (i2c->msg) {
> +       } else if (i2c->msg && (!i2c->highmode_enter)) {
>                 if (isr & ISR_ITE)
>                         i2c_pxa_irq_txempty(i2c, isr);
>                 if (isr & ISR_IRF)
>                         i2c_pxa_irq_rxfull(i2c, isr);
> +       } else if ((isr & ISR_ITE) && i2c->highmode_enter) {
> +               i2c->highmode_enter = false;
> +               wake_up(&i2c->wait);
>         } else {
>                 i2c_pxa_scream_blue_murder(i2c, "spurious irq");
>         }
> @@ -1088,6 +1134,11 @@ static int i2c_pxa_probe_pdata(struct platform_device *pdev,
>         if (plat) {
>                 i2c->use_pio = plat->use_pio;
>                 i2c->fast_mode = plat->fast_mode;
> +               i2c->high_mode = plat->high_mode;
> +               i2c->master_code = plat->master_code;
> +               if (!i2c->master_code)
> +                       i2c->master_code = 0xe;
> +               i2c->rate = plat->rate;
>         }
>         return 0;
>  }
> @@ -1160,6 +1211,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
>         i2c->irq = irq;
>
>         i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
> +       i2c->highmode_enter = false;
>
>         if (plat) {
>  #ifdef CONFIG_I2C_PXA_SLAVE
> @@ -1169,6 +1221,20 @@ static int i2c_pxa_probe(struct platform_device *dev)
>                 i2c->adap.class = plat->class;
>         }
>
> +       if (i2c->high_mode) {
> +               if (i2c_type != REGS_PXA910) {
> +                       pr_warn("i2c: <%s> do not support HS mode\n",
> +                               i2c->adap.name);
> +                       i2c->high_mode = 0;
> +               } else if (i2c->rate) {
> +                       clk_set_rate(i2c->clk, i2c->rate);
> +                       pr_info("i2c: <%s> set rate to %ld\n",
> +                               i2c->adap.name, clk_get_rate(i2c->clk));
> +               } else
> +                       pr_warn("i2c: <%s> clock rate not set\n",
> +                               i2c->adap.name);
> +       }
> +
>         clk_prepare_enable(i2c->clk);
>
>         if (i2c->use_pio) {
> diff --git a/include/linux/i2c/pxa-i2c.h b/include/linux/i2c/pxa-i2c.h
> index 1a9f65e..53aab24 100644
> --- a/include/linux/i2c/pxa-i2c.h
> +++ b/include/linux/i2c/pxa-i2c.h
> @@ -67,6 +67,9 @@ struct i2c_pxa_platform_data {
>         unsigned int            class;
>         unsigned int            use_pio :1;
>         unsigned int            fast_mode :1;
> +       unsigned int            high_mode:1;
> +       unsigned char           master_code;
> +       unsigned long           rate;
>  };
>
>  extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);
> --
> 1.7.4.1
>
> --
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Wolfram Sang - Aug. 15, 2013, 12:39 p.m.
On Thu, Aug 15, 2013 at 06:48:28PM +0800, James Lebron wrote:
> Hi Guys
> 
> Any comments?

As I wrote on August, 7th, I accepted the last version already; it is
also in linux-next since then. So, this series is not needed if the only
thing changed was the addition of the PXA910 register set. Since you
didn't write a changelog (please always do) I assume there are no
further changes.
James Lebron - Aug. 16, 2013, 7:27 a.m.
Hi Wolfram,

Thanks for your quick response!

Do you mean my initial patch has already been accept and I don't need
to push patch v2?
If yes, do I need to rebase the patch?

And sorry for don't write changelog.

Best regards,
Leilei

2013/8/15 Wolfram Sang <wsa@the-dreams.de>:
> On Thu, Aug 15, 2013 at 06:48:28PM +0800, James Lebron wrote:
>> Hi Guys
>>
>> Any comments?
>
> As I wrote on August, 7th, I accepted the last version already; it is
> also in linux-next since then. So, this series is not needed if the only
> thing changed was the addition of the PXA910 register set. Since you
> didn't write a changelog (please always do) I assume there are no
> further changes.
>
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James Lebron - Aug. 22, 2013, 2:02 a.m.
Hi Wolfram,

Did I misunderstand something?

Best regards,
Leilei

2013/8/16 James Lebron <leileishangchina@gmail.com>:
> Hi Wolfram,
>
> Thanks for your quick response!
>
> Do you mean my initial patch has already been accept and I don't need
> to push patch v2?
> If yes, do I need to rebase the patch?
>
> And sorry for don't write changelog.
>
> Best regards,
> Leilei
>
> 2013/8/15 Wolfram Sang <wsa@the-dreams.de>:
>> On Thu, Aug 15, 2013 at 06:48:28PM +0800, James Lebron wrote:
>>> Hi Guys
>>>
>>> Any comments?
>>
>> As I wrote on August, 7th, I accepted the last version already; it is
>> also in linux-next since then. So, this series is not needed if the only
>> thing changed was the addition of the PXA910 register set. Since you
>> didn't write a changelog (please always do) I assume there are no
>> further changes.
>>
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Wolfram Sang - Aug. 22, 2013, 5:33 a.m.
> Did I misunderstand something?

No, you didn't. As I said the patch is already in my tree and
linux-next. Please read Documentation/development-process/* in case you
don't know about linux-next yet.

Regards,

   Wolfram

Patch

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 3a5c477..da7b9ae 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -119,6 +119,8 @@  MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
 #define ICR_SADIE	(1 << 13)	   /* slave address detected int enable */
 #define ICR_UR		(1 << 14)	   /* unit reset */
 #define ICR_FM		(1 << 15)	   /* fast mode */
+#define ICR_HS		(1 << 16)	   /* High Speed mode */
+#define ICR_GPIOEN	(1 << 19)	   /* enable GPIO mode for SCL in HS */
 
 #define ISR_RWM		(1 << 0)	   /* read/write mode */
 #define ISR_ACKNAK	(1 << 1)	   /* ack/nak status */
@@ -164,6 +166,10 @@  struct pxa_i2c {
 	int			irq;
 	unsigned int		use_pio :1;
 	unsigned int		fast_mode :1;
+	unsigned int		high_mode:1;
+	unsigned char		master_code;
+	unsigned long		rate;
+	bool			highmode_enter;
 };
 
 #define _IBMR(i2c)	((i2c)->reg_ibmr)
@@ -468,6 +474,7 @@  static void i2c_pxa_reset(struct pxa_i2c *i2c)
 
 	/* set control register values */
 	writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
+	writel(readl(_ICR(i2c)) | (i2c->high_mode ? ICR_HS : 0), _ICR(i2c));
 
 #ifdef CONFIG_I2C_PXA_SLAVE
 	dev_info(&i2c->adap.dev, "Enabling slave mode\n");
@@ -689,6 +696,34 @@  static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
 	return 0;
 }
 
+/*
+ * PXA I2C send master code
+ * 1. Load master code to IDBR and send it.
+ *    Note for HS mode, set ICR [GPIOEN].
+ * 2. Wait until win arbitration.
+ */
+static int i2c_pxa_send_mastercode(struct pxa_i2c *i2c)
+{
+	u32 icr;
+	long timeout;
+
+	spin_lock_irq(&i2c->lock);
+	i2c->highmode_enter = true;
+	writel(i2c->master_code, _IDBR(i2c));
+
+	icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE);
+	icr |= ICR_GPIOEN | ICR_START | ICR_TB | ICR_ITEIE;
+	writel(icr, _ICR(i2c));
+
+	spin_unlock_irq(&i2c->lock);
+	timeout = wait_event_timeout(i2c->wait,
+			i2c->highmode_enter == false, HZ * 1);
+
+	i2c->highmode_enter = false;
+
+	return (timeout == 0) ? I2C_RETRY : 0;
+}
+
 static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
 			       struct i2c_msg *msg, int num)
 {
@@ -752,6 +787,14 @@  static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
 		goto out;
 	}
 
+	if (i2c->high_mode) {
+		ret = i2c_pxa_send_mastercode(i2c);
+		if (ret) {
+			dev_err(&i2c->adap.dev, "i2c_pxa_send_mastercode timeout\n");
+			goto out;
+			}
+	}
+
 	spin_lock_irq(&i2c->lock);
 
 	i2c->msg = msg;
@@ -999,11 +1042,14 @@  static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id)
 			i2c_pxa_slave_txempty(i2c, isr);
 		if (isr & ISR_IRF)
 			i2c_pxa_slave_rxfull(i2c, isr);
-	} else if (i2c->msg) {
+	} else if (i2c->msg && (!i2c->highmode_enter)) {
 		if (isr & ISR_ITE)
 			i2c_pxa_irq_txempty(i2c, isr);
 		if (isr & ISR_IRF)
 			i2c_pxa_irq_rxfull(i2c, isr);
+	} else if ((isr & ISR_ITE) && i2c->highmode_enter) {
+		i2c->highmode_enter = false;
+		wake_up(&i2c->wait);
 	} else {
 		i2c_pxa_scream_blue_murder(i2c, "spurious irq");
 	}
@@ -1088,6 +1134,11 @@  static int i2c_pxa_probe_pdata(struct platform_device *pdev,
 	if (plat) {
 		i2c->use_pio = plat->use_pio;
 		i2c->fast_mode = plat->fast_mode;
+		i2c->high_mode = plat->high_mode;
+		i2c->master_code = plat->master_code;
+		if (!i2c->master_code)
+			i2c->master_code = 0xe;
+		i2c->rate = plat->rate;
 	}
 	return 0;
 }
@@ -1160,6 +1211,7 @@  static int i2c_pxa_probe(struct platform_device *dev)
 	i2c->irq = irq;
 
 	i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
+	i2c->highmode_enter = false;
 
 	if (plat) {
 #ifdef CONFIG_I2C_PXA_SLAVE
@@ -1169,6 +1221,20 @@  static int i2c_pxa_probe(struct platform_device *dev)
 		i2c->adap.class = plat->class;
 	}
 
+	if (i2c->high_mode) {
+		if (i2c_type != REGS_PXA910) {
+			pr_warn("i2c: <%s> do not support HS mode\n",
+				i2c->adap.name);
+			i2c->high_mode = 0;
+		} else if (i2c->rate) {
+			clk_set_rate(i2c->clk, i2c->rate);
+			pr_info("i2c: <%s> set rate to %ld\n",
+				i2c->adap.name, clk_get_rate(i2c->clk));
+		} else
+			pr_warn("i2c: <%s> clock rate not set\n",
+				i2c->adap.name);
+	}
+
 	clk_prepare_enable(i2c->clk);
 
 	if (i2c->use_pio) {
diff --git a/include/linux/i2c/pxa-i2c.h b/include/linux/i2c/pxa-i2c.h
index 1a9f65e..53aab24 100644
--- a/include/linux/i2c/pxa-i2c.h
+++ b/include/linux/i2c/pxa-i2c.h
@@ -67,6 +67,9 @@  struct i2c_pxa_platform_data {
 	unsigned int		class;
 	unsigned int		use_pio :1;
 	unsigned int		fast_mode :1;
+	unsigned int		high_mode:1;
+	unsigned char		master_code;
+	unsigned long		rate;
 };
 
 extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);