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Message-ID: <514ab93f-ba2e-2799-003d-2cb484079c56@st.com>
Date: Mon, 13 May 2019 11:21:44 +0000
From: Philippe CORNU <philippe.cornu@...com>
To: Yannick FERTRE <yannick.fertre@...com>,
Benjamin GAIGNARD <benjamin.gaignard@...com>,
Vincent ABRIOU <vincent.abriou@...com>,
"David Airlie" <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre TORGUE <alexandre.torgue@...com>,
"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-stm32@...md-mailman.stormreply.com"
<linux-stm32@...md-mailman.stormreply.com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] drm/stm: dsi: add support of an optional regulator
Hi Yannick,
On 5/10/19 6:16 PM, Philippe Cornu wrote:
> Dear Yannick,
> Thank you for your patch,
>
> I like better the new shorter commit heading, thank you.
>
>
> On 5/10/19 4:20 PM, Yannick Fertré wrote:
>> Add support of an optional regulator for the phy part of the DSI
>> controller.
>>
>> Signed-off-by: Yannick Fertré <yannick.fertre@...com>
>> ---
>> drivers/gpu/drm/stm/dw_mipi_dsi-stm.c | 45
>> ++++++++++++++++++++++++++++++-----
>> 1 file changed, 39 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
>> b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
>> index 1bef73e..22bd095 100644
>> --- a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
>> +++ b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
>> @@ -9,6 +9,7 @@
>> #include <linux/clk.h>
>> #include <linux/iopoll.h>
>> #include <linux/module.h>
>> +#include <linux/regulator/consumer.h>
>> #include <drm/drmP.h>
>> #include <drm/drm_mipi_dsi.h>
>> #include <drm/bridge/dw_mipi_dsi.h>
>> @@ -76,6 +77,7 @@ struct dw_mipi_dsi_stm {
>> u32 hw_version;
>> int lane_min_kbps;
>> int lane_max_kbps;
>> + struct regulator *vdd_supply;
>> };
>> static inline void dsi_write(struct dw_mipi_dsi_stm *dsi, u32 reg,
>> u32 val)
>> @@ -318,17 +320,31 @@ static int dw_mipi_dsi_stm_probe(struct
>> platform_device *pdev)
>> return PTR_ERR(dsi->base);
>> }
>> + dsi->vdd_supply = devm_regulator_get_optional(dev, "phy-dsi");
>> + if (IS_ERR(dsi->vdd_supply)) {
>> + ret = PTR_ERR(dsi->vdd_supply);
>> + if (ret != -EPROBE_DEFER)
>> + DRM_ERROR("failed to request regulator: %d\n", ret);
>> + return ret;
>> + }
I did more tests on a stm32f469 disco board and this above code does not
work (the ret value is -ENODEV)
Two possibilities then:
1) remove the _optional (but we have the "using dummy regulator"
message, I am fine with it)
or
2) handle -ENODEV but do not forget to check vdd_supply!=NULL before
calling all regulator_(enable/disable)
if (ret != -ENODEV) {
if (ret != -EPROBE_DEFER)
DRM_ERROR("failed to request regulator: %d\n",
ret);
return ret;
}
dsi->vdd_supply = NULL;
}
if (dsi->vdd_supply) {
ret = regulator_enable(dsi->vdd_supply);
...
if (dsi->vdd_supply)
regulator_disable(dsi->vdd_supply);
I let you choose your favorite one.
Thank you,
Philippe
>> +
>> + ret = regulator_enable(dsi->vdd_supply);
>> + if (ret) {
>> + DRM_ERROR("failed to enable regulator: %d\n", ret);
>> + return ret;
>> + }
>> +
>> dsi->pllref_clk = devm_clk_get(dev, "ref");
>> if (IS_ERR(dsi->pllref_clk)) {
>> ret = PTR_ERR(dsi->pllref_clk);
>> - dev_err(dev, "Unable to get pll reference clock: %d\n", ret);
>> - return ret;
>> + DRM_ERROR("Unable to get pll reference clock: %d\n", ret);
>> + goto err_clk_get;
>> }
>> ret = clk_prepare_enable(dsi->pllref_clk);
>> if (ret) {
>> - dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
>> - return ret;
>> + DRM_ERROR("%s: Failed to enable pllref_clk\n", __func__);
>> + goto err_clk_get;
>> }
>> dw_mipi_dsi_stm_plat_data.base = dsi->base;
>> @@ -339,11 +355,19 @@ static int dw_mipi_dsi_stm_probe(struct
>> platform_device *pdev)
>> dsi->dsi = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
>> if (IS_ERR(dsi->dsi)) {
>> DRM_ERROR("Failed to initialize mipi dsi host\n");
>> - clk_disable_unprepare(dsi->pllref_clk);
>> - return PTR_ERR(dsi->dsi);
>> + ret = PTR_ERR(dsi->dsi);
>> + goto err_dsi_probe;
>> }
>> return 0;
>> +
>> +err_dsi_probe:
>> + clk_disable_unprepare(dsi->pllref_clk);
>> +err_clk_get:
>> + regulator_disable(dsi->vdd_supply);
>> +
>> + return ret;
>> +
>> }
>> static int dw_mipi_dsi_stm_remove(struct platform_device *pdev)
>> @@ -351,6 +375,7 @@ static int dw_mipi_dsi_stm_remove(struct
>> platform_device *pdev)
>> struct dw_mipi_dsi_stm *dsi = platform_get_drvdata(pdev);
>> clk_disable_unprepare(dsi->pllref_clk);
>> + regulator_disable(dsi->vdd_supply);
>> dw_mipi_dsi_remove(dsi->dsi);
>
> for a future patch: we may have a different order
> dw_mipi_dsi_remove(dsi->dsi);
> clk_disable_unprepare(dsi->pllref_clk);
> regulator_disable(dsi->vdd_supply);
>
>> return 0;
>> @@ -363,6 +388,7 @@ static int __maybe_unused
>> dw_mipi_dsi_stm_suspend(struct device *dev)
>> DRM_DEBUG_DRIVER("\n");
>> clk_disable_unprepare(dsi->pllref_clk);
>> + regulator_disable(dsi->vdd_supply);
>> return 0;
>> }
>> @@ -370,9 +396,16 @@ static int __maybe_unused
>> dw_mipi_dsi_stm_suspend(struct device *dev)
>> static int __maybe_unudw_mipi_dsi_remove(dsi->dsi);sed
>> dw_mipi_dsi_stm_resume(struct device *dev)
>> {
>> struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
>> + int ret;
>> DRM_DEBUG_DRIVER("\n");
>> + ret = regulator_enable(dsi->vdd_supply);
>> + if (ret) {
>> + DRM_ERROR("failed to enable regulator: %d\n", ret);
>> + return ret;
>> + }
>> +
>> clk_prepare_enable(dsi->pllref_clk);
>
> for a future patch: we may check clk_prepare_enable return value.
>
>> return 0;
>>
>
>
> Acked-by: Philippe Cornu <philippe.cornu@...com>
>
> Philippe :)
>
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