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From: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
To: linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	martin.petersen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org,
	avri.altman-Sjgp3cTcYWE@public.gmane.org,
	alim.akhtar-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
	pedrom.sousa-HKixBCOQz3hWk0Htik3J/w@public.gmane.org
Cc: marc.w.gonzalez-GANU6spQydw@public.gmane.org,
	chun-hung.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	kuohong.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	peter.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
Subject: [PATCH RESEND v3 5/5] scsi: ufs: Remove "<name>-fixed-regulator" device tree property
Date: Wed, 27 Mar 2019 17:58:27 +0800	[thread overview]
Message-ID: <1553680707-28579-6-git-send-email-stanley.chu@mediatek.com> (raw)
In-Reply-To: <1553680707-28579-1-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>

"<name>-fixed-regulator" device tree property can be
safely removed because below things are fixed or resolved,

1. "<name>-max-microamp" becomes optional property: Undefined
   "<name>-max-microamp" will not cause initialization fail if
   "<name>-fixed-regulator" is not defined.

2. Current switching operation (by regulator_set_load) now has rules:
   Regulators will have undefined current limit if
   "<name>-fixed-regulator" is not defined. But this is safe because
   only regulator which has configured current limit from
   "<name>-max-microamp" property is allowed to change its load.

Although "<name>-fixed-regulator" is not used in any dt-bindings
in tree, this patch is still safe for regulators already defined
"<name>-fixed-regulator". To be more clear, if a regulator defined
"<name>-fixed-regulator" before, the behavior difference after
this patch is,

1. "<name>-max-microamp":
   If a regulator defined "<name>-fixed-regulator", it is not necessary
   to define "<name>-max-microamp" property in device tree and it is
   expected to have an undefined current limit, i.e., "max_uA" field
   is zero in struct ufs_vreg. This is exactly the same as patched.

2. "vcc-supply-1p8" or volatge range settings:
   * For vcc, vccq or vccq2, these three regulators shall not define
     "<name>-fixed-regulator" because defining it will lead to
     undefined voltage range and thus voltage switching will be
     unexpected.
   * For other regulators with undefined voltage range, voltage range
     will be still undefined after patched.

Therefore this patch is safe for all existed regulators with
"<name>-fixed-regulator" property already defined.

Signed-off-by: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 drivers/scsi/ufs/ufshcd-pltfrm.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index 2420e6962219..7b404df965b2 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -151,11 +151,6 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
 
 	vreg->name = kstrdup(name, GFP_KERNEL);
 
-	/* if fixed regulator no need further initialization */
-	snprintf(prop_name, MAX_PROP_SIZE, "%s-fixed-regulator", name);
-	if (of_property_read_bool(np, prop_name))
-		goto out;
-
 	snprintf(prop_name, MAX_PROP_SIZE, "%s-max-microamp", name);
 	if (of_property_read_u32(np, prop_name, &vreg->max_uA)) {
 		dev_info(dev, "%s: unable to find %s\n", __func__, prop_name);
-- 
2.18.0

  parent reply	other threads:[~2019-03-27  9:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-27  9:58 [PATCH RESEND v3 0/5] scsi: ufs: Fix regulator operations and remove "<name>-fixed-regulator" device tree property Stanley Chu
     [not found] ` <1553680707-28579-1-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-27  9:58   ` [PATCH RESEND v3 1/5] scsi: ufs: Remove unused min_uA field in struct ufs_vreg Stanley Chu
2019-03-27  9:58   ` [PATCH RESEND v3 2/5] scsi: ufs: Avoid configuring regulator with undefined voltage range Stanley Chu
     [not found]     ` <1553680707-28579-3-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-27 10:35       ` Avri Altman
2019-03-27  9:58   ` [PATCH RESEND v3 3/5] scsi: ufs: Fix regulator load and icc-level configuration Stanley Chu
     [not found]     ` <1553680707-28579-4-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-27 10:55       ` Avri Altman
2019-03-27  9:58   ` [PATCH RESEND v3 4/5] scsi: ufs: Change "<name>-max-microamp" to non-mandatory property Stanley Chu
     [not found]     ` <1553680707-28579-5-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-27 10:48       ` Avri Altman
2019-03-27  9:58   ` Stanley Chu [this message]
2019-03-27 10:57   ` [PATCH RESEND v3 0/5] scsi: ufs: Fix regulator operations and remove "<name>-fixed-regulator" device tree property Avri Altman
     [not found]     ` <SN6PR04MB49250E97111EB8975E0ED7EFFC580-UKdxhu0+N/VnT3GYGerMaFM8qxBPnqtHvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2019-03-27 13:24       ` Stanley Chu
2019-03-27 17:18   ` Alim Akhtar
     [not found]     ` <CAGOxZ51zdtoLz=E_vmpwt+2wTJq32yUQa=h_OiV7qO1N-c=NUA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-28  1:21       ` Stanley Chu

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