[v8,8/8] i2c: rk3x: support fast-mode plus for rk3399
diff mbox

Message ID 1462908794-27333-1-git-send-email-david.wu@rock-chips.com
State New
Headers show

Commit Message

David Wu May 10, 2016, 7:33 p.m. UTC
Signed-off-by: David Wu <david.wu@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
Change in v8:
- None

 drivers/i2c/busses/i2c-rk3x.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

Comments

Caesar Wang May 11, 2016, 11:44 a.m. UTC | #1
? 2016?05?11? 03:33, David Wu ??:
> Signed-off-by: David Wu <david.wu@rock-chips.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

Tested-by: Caesar Wang <wxt@rock-chips.com>
> ---
> Change in v8:
> - None
>
>   drivers/i2c/busses/i2c-rk3x.c | 21 +++++++++++++++++----
>   1 file changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index 25ed1ad..0ba25ee 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -126,6 +126,17 @@ static const struct i2c_spec_values fast_mode_spec = {
>   	.min_hold_buffer_ns = 1300,
>   };
>   
> +static const struct i2c_spec_values fast_mode_plus_spec = {
> +	.min_hold_start_ns = 260,
> +	.min_low_ns = 500,
> +	.min_high_ns = 260,
> +	.min_setup_start_ns = 260,
> +	.max_data_hold_ns = 400,
> +	.min_data_setup_ns = 50,
> +	.min_setup_stop_ns = 260,
> +	.min_hold_buffer_ns = 500,
> +};
> +
>   /**
>    * struct rk3x_i2c_calced_timings:
>    * @div_low: Divider output for low
> @@ -531,8 +542,10 @@ static const struct i2c_spec_values *rk3x_i2c_get_spec(unsigned int speed)
>   {
>   	if (speed <= 100000)
>   		return &standard_mode_spec;
> -	else
> +	else if (speed <= 400000)
>   		return &fast_mode_spec;
> +	else
> +		return &fast_mode_plus_spec;
>   }
>   
>   /**
> @@ -743,9 +756,9 @@ static int rk3x_i2c_v1_calc_timings(unsigned long clk_rate,
>   	const struct i2c_spec_values *spec;
>   	int ret = 0;
>   
> -	/* Support standard-mode and fast-mode */
> -	if (WARN_ON(t->bus_freq_hz > 400000))
> -		t->bus_freq_hz = 400000;
> +	/* Support standard-mode, fast-mode and fast-mode plus */
> +	if (WARN_ON(t->bus_freq_hz > 1000000))
> +		t->bus_freq_hz = 1000000;
>   
>   	/* prevent scl_rate_khz from becoming 0 */
>   	if (WARN_ON(t->bus_freq_hz < 1000))
Heiko Stübner May 11, 2016, 9:09 p.m. UTC | #2
Am Mittwoch, 11. Mai 2016, 03:33:14 schrieb David Wu:

please always try to also provide some sort of commit message.

---
Implement fast mode plus that allows bus speeds of up to 1MHz.
.....

---

Additionally, the i2c-noob in me would wish for a short sentence on where 
the timing values come from (measured, somewhere in the TRM I didn't find or 
something completely different).


Patch content itself looks good, so with a suitable commit message,
Reviewed-by: Heiko Stuebner <heiko@sntech.de>


> Signed-off-by: David Wu <david.wu@rock-chips.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---
> Change in v8:
> - None
> 
>  drivers/i2c/busses/i2c-rk3x.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index 25ed1ad..0ba25ee 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -126,6 +126,17 @@ static const struct i2c_spec_values fast_mode_spec =
> { .min_hold_buffer_ns = 1300,
>  };
> 
> +static const struct i2c_spec_values fast_mode_plus_spec = {
> +	.min_hold_start_ns = 260,
> +	.min_low_ns = 500,
> +	.min_high_ns = 260,
> +	.min_setup_start_ns = 260,
> +	.max_data_hold_ns = 400,
> +	.min_data_setup_ns = 50,
> +	.min_setup_stop_ns = 260,
> +	.min_hold_buffer_ns = 500,
> +};
> +
>  /**
>   * struct rk3x_i2c_calced_timings:
>   * @div_low: Divider output for low
> @@ -531,8 +542,10 @@ static const struct i2c_spec_values
> *rk3x_i2c_get_spec(unsigned int speed) {
>  	if (speed <= 100000)
>  		return &standard_mode_spec;
> -	else
> +	else if (speed <= 400000)
>  		return &fast_mode_spec;
> +	else
> +		return &fast_mode_plus_spec;
>  }
> 
>  /**
> @@ -743,9 +756,9 @@ static int rk3x_i2c_v1_calc_timings(unsigned long
> clk_rate, const struct i2c_spec_values *spec;
>  	int ret = 0;
> 
> -	/* Support standard-mode and fast-mode */
> -	if (WARN_ON(t->bus_freq_hz > 400000))
> -		t->bus_freq_hz = 400000;
> +	/* Support standard-mode, fast-mode and fast-mode plus */
> +	if (WARN_ON(t->bus_freq_hz > 1000000))
> +		t->bus_freq_hz = 1000000;
> 
>  	/* prevent scl_rate_khz from becoming 0 */
>  	if (WARN_ON(t->bus_freq_hz < 1000))
Doug Anderson May 11, 2016, 11:41 p.m. UTC | #3
Heiko,

On Wed, May 11, 2016 at 2:09 PM, Heiko Stuebner <heiko@sntech.de> wrote:
> Additionally, the i2c-noob in me would wish for a short sentence on where
> the timing values come from (measured, somewhere in the TRM I didn't find or
> something completely different).

If you search for "UM10204" you'll find the first link is
<http://www.nxp.com/documents/user_manual/UM10204.pdf>.  That appears
to be the official standard.  At least that's what
<http://www.i2c-bus.org/fast-mode-plus/> says (though they have an old
link).

Agree that it wouldn't hurt to mention that in the commit message.

-Doug
Heiko Stübner May 12, 2016, 8:30 a.m. UTC | #4
Am Mittwoch, 11. Mai 2016, 16:41:54 schrieb Doug Anderson:
> Heiko,
> 
> On Wed, May 11, 2016 at 2:09 PM, Heiko Stuebner <heiko@sntech.de> wrote:
> > Additionally, the i2c-noob in me would wish for a short sentence on
> > where
> > the timing values come from (measured, somewhere in the TRM I didn't
> > find or something completely different).
> 
> If you search for "UM10204" you'll find the first link is
> <http://www.nxp.com/documents/user_manual/UM10204.pdf>.  That appears
> to be the official standard.  At least that's what
> <http://www.i2c-bus.org/fast-mode-plus/> says (though they have an old
> link).

I did find that document yesterday, but was to blind and somehow only saw the 
separate table for highspeed-timings. On a closer look, I now also found the 
timing-table for the other modes [due to the bigger font-size used there? 
;-) ]

Patch
diff mbox

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 25ed1ad..0ba25ee 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -126,6 +126,17 @@  static const struct i2c_spec_values fast_mode_spec = {
 	.min_hold_buffer_ns = 1300,
 };
 
+static const struct i2c_spec_values fast_mode_plus_spec = {
+	.min_hold_start_ns = 260,
+	.min_low_ns = 500,
+	.min_high_ns = 260,
+	.min_setup_start_ns = 260,
+	.max_data_hold_ns = 400,
+	.min_data_setup_ns = 50,
+	.min_setup_stop_ns = 260,
+	.min_hold_buffer_ns = 500,
+};
+
 /**
  * struct rk3x_i2c_calced_timings:
  * @div_low: Divider output for low
@@ -531,8 +542,10 @@  static const struct i2c_spec_values *rk3x_i2c_get_spec(unsigned int speed)
 {
 	if (speed <= 100000)
 		return &standard_mode_spec;
-	else
+	else if (speed <= 400000)
 		return &fast_mode_spec;
+	else
+		return &fast_mode_plus_spec;
 }
 
 /**
@@ -743,9 +756,9 @@  static int rk3x_i2c_v1_calc_timings(unsigned long clk_rate,
 	const struct i2c_spec_values *spec;
 	int ret = 0;
 
-	/* Support standard-mode and fast-mode */
-	if (WARN_ON(t->bus_freq_hz > 400000))
-		t->bus_freq_hz = 400000;
+	/* Support standard-mode, fast-mode and fast-mode plus */
+	if (WARN_ON(t->bus_freq_hz > 1000000))
+		t->bus_freq_hz = 1000000;
 
 	/* prevent scl_rate_khz from becoming 0 */
 	if (WARN_ON(t->bus_freq_hz < 1000))