* Re: [PATCH 1/2 v3] i2c: exynos5: add support for HSI2C on Exynos5260 SoC
[not found] ` <52F38EA4.10805@samsung.com>
@ 2014-02-06 13:50 ` Tomasz Figa
[not found] ` <52F3933B.9090202-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Tomasz Figa @ 2014-02-06 13:50 UTC (permalink / raw)
To: Naveen Krishna Chatradhi, linux-samsung-soc, linux-i2c
Cc: linux-arm-kernel, devicetree@vger.kernel.org, naveenkrishna.ch,
kgene.kim, grant.likely, Wolfram Sang, linux-kernel, taeggyun.ko,
balbi, cpgs
Also, please use correct addresses of DT ML and Wolfram's e-mail (fixed
in this message).
Best regards,
Tomasz
On 06.02.2014 14:31, Tomasz Figa wrote:
> Hi Naveen,
>
> On 06.02.2014 13:06, Naveen Krishna Chatradhi wrote:
>> This patch implements a variant struct to handle the differences
>> (like fifo_depths) in the HSI2C modules across SoCs.
>>
>> Adds a new compatible to support HSI2C module on Exynos5260.
>> Also resets the module as an init sequence (Needed by Exynos5260).
>>
>> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
>> ---
>> Changes since v2:
>> 1. Used variant struct as suggested by Tomasz Figa.
>> 2. Change compatible strings from samsung,exynos5-hsi2c to
>> samsung,exynos5250-hsi2c based on the first SoC to see the feature.
>> 3. Using reset as init sequences.
>> 4. Merged the 2 patches into one.
>>
>> .../devicetree/bindings/i2c/i2c-exynos5.txt | 8 ++-
>> drivers/i2c/busses/i2c-exynos5.c | 64
>> ++++++++++++++++----
>> 2 files changed, 58 insertions(+), 14 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
>> b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
>> index 056732c..5bc4998 100644
>> --- a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
>> +++ b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
>> @@ -5,7 +5,11 @@ at various speeds ranging from 100khz to 3.4Mhz.
>>
>> Required properties:
>> - compatible: value should be.
>> - -> "samsung,exynos5-hsi2c", for i2c compatible with exynos5 hsi2c.
>
> Device tree bindings need to be backwards compatible, so you need to
> keep this compatible string supported, just marked as (DEPRECATED).
>
> Driver-wise, it will use the same driver data / variant struct as
> "samsung,exynos5250-hsi2c", just one more entry in OF match table is
> needed.
>
>> + -> "samsung,exynos5250-hsi2c", for i2c compatible with HSI2C
>> available
>> + on Exynos5250 and Exynos5420 SoCs.
>> + -> "samsung,exynos5260-hsi2c", for i2c compatible with HSI2C
>> available
>> + on Exynos5260 SoCs.
>> +
>> - reg: physical base address of the controller and length of
>> memory mapped
>> region.
>> - interrupts: interrupt number to the cpu.
>> @@ -26,7 +30,7 @@ Optional properties:
>> Example:
>>
>> hsi2c@12ca0000 {
>> - compatible = "samsung,exynos5-hsi2c";
>> + compatible = "samsung,exynos5250-hsi2c";
>> reg = <0x12ca0000 0x100>;
>> interrupts = <56>;
>> clock-frequency = <100000>;
>
> [snip]
>
>> @@ -483,6 +514,7 @@ static void exynos5_i2c_message_start(struct
>> exynos5_i2c *i2c, int stop)
>> u32 i2c_auto_conf = 0;
>> u32 fifo_ctl;
>> unsigned long flags;
>> + unsigned short trig_lvl;
>>
>> i2c_ctl = readl(i2c->regs + HSI2C_CTL);
>> i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
>> @@ -493,13 +525,19 @@ static void exynos5_i2c_message_start(struct
>> exynos5_i2c *i2c, int stop)
>>
>> i2c_auto_conf = HSI2C_READ_WRITE;
>>
>> - fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(HSI2C_DEF_TXFIFO_LVL);
>> + trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ?
>> + (i2c->variant->fifo_depth * 3/4) : i2c->msg->len;
>> + fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(trig_lvl);
>> +
>
> This is a rather serious semantic change, that doesn't look to belong to
> this patch. If this is needed, it should be done in a separate patch.
>
>> int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN |
>> HSI2C_INT_TRAILING_EN);
>> } else {
>> i2c_ctl |= HSI2C_TXCHON;
>>
>> - fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(HSI2C_DEF_RXFIFO_LVL);
>> + trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ?
>> + (i2c->variant->fifo_depth * 1/4) : i2c->msg->len;
>> + fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(trig_lvl);
>> +
>
> Ditto.
>
> Best regards,
> Tomasz
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