linux-kernel - Re: [PATCH] spmi: pmic_arb: add support for hw version 2

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Date:	Sat, 24 Jan 2015 10:14:54 +0200
From:	Stanimir Varbanov <svarbanov@...sol.com>
To:	Gilad Avidov <gavidov@...eaurora.org>
CC:	sdharia@...eaurora.org, mlocke@...eaurora.org,
	linux-arm-msm@...r.kernel.org, gregkh@...uxfoundation.org,
	linux-kernel@...r.kernel.org, iivanov@...sol.com,
	galak@...eaurora.org, agross@...eaurora.org
Subject: Re: [PATCH] spmi: pmic_arb: add support for hw version 2

Hi Gilad,

<snip>

>>
>>>   -/* Non-data command */
>>> -static int pmic_arb_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid)
>>> +static int
>>> +pmic_arb_non_data_cmd_v1(struct spmi_controller *ctrl, u8 opc, u8 sid)
>>>   {
>>>       struct spmi_pmic_arb_dev *pmic_arb =
>>> spmi_controller_get_drvdata(ctrl);
>>>       unsigned long flags;
>>>       u32 cmd;
>>>       int rc;
>>> -
>>> -    /* Check for valid non-data command */
>>> -    if (opc < SPMI_CMD_RESET || opc > SPMI_CMD_WAKEUP)
>>> -        return -EINVAL;
>>> +    u32 offset = pmic_arb->ver->offset(pmic_arb, sid, 0);
>>>         cmd = ((opc | 0x40) << 27) | ((sid & 0xf) << 20);
>>>         raw_spin_lock_irqsave(&pmic_arb->lock, flags);
>>> -    pmic_arb_base_write(pmic_arb, PMIC_ARB_CMD(pmic_arb->channel),
>>> cmd);
>>> -    rc = pmic_arb_wait_for_done(ctrl);
>>> +    pmic_arb_base_write(pmic_arb, offset + PMIC_ARB_CMD, cmd);
>>> +    rc = pmic_arb_wait_for_done(ctrl, pmic_arb->wr_base, sid, 0);
>>>       raw_spin_unlock_irqrestore(&pmic_arb->lock, flags);
>>>         return rc;
>>>   }
>>>   +/* Unsupported by HW */
>>> +static int
>>> +pmic_arb_non_data_cmd_v2(struct spmi_controller *ctrl, u8 opc, u8 sid)
>>> +{
>>> +    return -EOPNOTSUPP;
>>> +}
> 
> Hi Stanimir,
> 
>> Does pmic arbiter v2 supports SPMI_CMD_WAKEUP and SPMI_CMD_SHUTDOWN
>> commands? If so how we send those commands to the arbiter when the
> pmic-arbiter v2 does not support non-data commands including the two
> that you have mentioned above.
>> .non_data_cmd operation returns EOPNOTSUPP. If we returning EOPNOTSUPP
>> the spmi bus .probe method will not call spmi driver .probe. See spmi.c
>> spmi_drv_probe().
> Very keen observation!
> 
> The slaves that I'm working on do not need nor support the wakeup command.
> I'll add a patch to add a new device tree boolean property to the
> framework, maybe "skip-wakeup", for similar slaves.
> Then change spmi_drv_probe() to skip the wakeup if the property is there.

No, instead of adding one more dt property just return zero from
.non_data_cmd operation and keep the comment that this is not supported
on v2. The other way is to fill the .non_data_cmd = NULL on v2 and add a
check for .non_data_cmd != NULL in the callers.

-- 
regards,
Stan
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