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Date: Mon, 27 May 2024 11:57:52 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Neil Armstrong <neil.armstrong@...aro.org>
Cc: Vinod Koul <vkoul@...nel.org>,
Kishon Vijay Abraham I <kishon@...nel.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konrad.dybcio@...aro.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/7] phy: qcom: qmp-combo: register a typec mux to
change the QPHY_MODE
On Mon, May 27, 2024 at 10:42:36AM +0200, Neil Armstrong wrote:
> Register a typec mux in order to change the PHY mode on the Type-C
> mux events depending on the mode and the svid when in Altmode setup.
>
> The DisplayPort phy should be left enabled if is still powered on
> by the DRM DisplayPort controller, so bail out until the DisplayPort
> PHY is not powered off.
>
> The Type-C Mode/SVID only changes on plug/unplug, and USB SAFE states
> will be set in between of USB-Only, Combo and DisplayPort Only so
> this will leave enough time to the DRM DisplayPort controller to
> turn of the DisplayPort PHY.
>
> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
> ---
> drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 123 ++++++++++++++++++++++++++++--
> 1 file changed, 118 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> index 788e4c05eaf2..b55ab08d44c2 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
> @@ -19,6 +19,7 @@
> #include <linux/reset.h>
> #include <linux/slab.h>
> #include <linux/usb/typec.h>
> +#include <linux/usb/typec_dp.h>
> #include <linux/usb/typec_mux.h>
>
> #include <drm/bridge/aux-bridge.h>
> @@ -1527,6 +1528,10 @@ struct qmp_combo {
>
> struct typec_switch_dev *sw;
> enum typec_orientation orientation;
> +
> + struct typec_mux_dev *mux;
> + unsigned long mux_mode;
> + unsigned int svid;
> };
>
> static void qmp_v3_dp_aux_init(struct qmp_combo *qmp);
> @@ -3353,17 +3358,112 @@ static int qmp_combo_typec_switch_set(struct typec_switch_dev *sw,
> return 0;
> }
>
> -static void qmp_combo_typec_unregister(void *data)
> +static int qmp_combo_typec_mux_set(struct typec_mux_dev *mux, struct typec_mux_state *state)
> +{
> + struct qmp_combo *qmp = typec_mux_get_drvdata(mux);
> + const struct qmp_phy_cfg *cfg = qmp->cfg;
> + enum qphy_mode new_mode;
> + unsigned int svid;
> +
> + if (state->mode == qmp->mode)
> + return 0;
> +
> + mutex_lock(&qmp->phy_mutex);
> +
> + if (state->alt)
> + svid = state->alt->svid;
> + else
> + svid = 0; // No SVID
> +
> + if (svid == USB_TYPEC_DP_SID) {
> + switch (state->mode) {
> + /* DP Only */
> + case TYPEC_DP_STATE_C:
> + case TYPEC_DP_STATE_E:
> + new_mode = QPHY_MODE_DP_ONLY;
> + break;
> +
> + /* DP + USB */
> + case TYPEC_DP_STATE_D:
> + case TYPEC_DP_STATE_F:
> +
> + /* Safe fallback...*/
> + default:
> + new_mode = QPHY_MODE_COMBO;
> + break;
> + }
> + } else {
> + /* Only switch to USB_ONLY when we know we only have USB3 */
> + if (qmp->mux_mode == TYPEC_MODE_USB3)
> + new_mode = QPHY_MODE_USB_ONLY;
> + else
> + new_mode = QPHY_MODE_COMBO;
> + }
> +
> + if (new_mode == qmp->init_mode) {
> + dev_dbg(qmp->dev, "typec_mux_set: same phy mode, bail out\n");
> + qmp->mode = state->mode;
> + goto out;
> + }
> +
> + if (qmp->init_mode != QPHY_MODE_USB_ONLY && qmp->dp_powered_on) {
> + dev_dbg(qmp->dev, "typec_mux_set: DP is still powered on, delaying switch\n");
> + goto out;
> + }
> +
> + dev_dbg(qmp->dev, "typec_mux_set: switching from phy mode %d to %d\n",
> + qmp->init_mode, new_mode);
> +
> + qmp->mux_mode = state->mode;
> + qmp->init_mode = new_mode;
> +
> + if (qmp->init_count) {
> + if (qmp->usb_init_count)
> + qmp_combo_usb_power_off(qmp->usb_phy);
> + if (qmp->dp_init_count)
> + writel(DP_PHY_PD_CTL_PSR_PWRDN, qmp->dp_dp_phy + QSERDES_DP_PHY_PD_CTL);
> + qmp_combo_com_exit(qmp, true);
> +
> + /* Now everything's powered down, power up the right PHYs */
> +
> + qmp_combo_com_init(qmp, true);
> + if (qmp->init_mode == QPHY_MODE_DP_ONLY && qmp->usb_init_count) {
> + qmp->usb_init_count--;
Can we move this clause next to actually powering USB part off?
> + } else if (qmp->init_mode != QPHY_MODE_DP_ONLY) {
> + qmp_combo_usb_power_on(qmp->usb_phy);
> + if (!qmp->usb_init_count)
> + qmp->usb_init_count++;
> + }
> + if (qmp->init_mode != QPHY_MODE_USB_ONLY && qmp->dp_init_count)
> + cfg->dp_aux_init(qmp);
Does dp_init_count reflect the actual necessity to bring up the DP part
up? Maybe we can unify the code between this function and
qmp_combo_typec_switch_set()? I don't like that it is unobvious whether
these two functions will results in the same state or not depending on
the order in which they are being called.
> + }
> +
> +out:
> + mutex_unlock(&qmp->phy_mutex);
> +
> + return 0;
> +}
> +
> +static void qmp_combo_typec_switch_unregister(void *data)
> {
> struct qmp_combo *qmp = data;
>
> typec_switch_unregister(qmp->sw);
> }
>
> -static int qmp_combo_typec_switch_register(struct qmp_combo *qmp)
> +static void qmp_combo_typec_mux_unregister(void *data)
> +{
> + struct qmp_combo *qmp = data;
> +
> + typec_mux_unregister(qmp->mux);
> +}
> +
> +static int qmp_combo_typec_register(struct qmp_combo *qmp)
> {
> struct typec_switch_desc sw_desc = {};
> + struct typec_mux_desc mux_desc = { };
> struct device *dev = qmp->dev;
> + int ret;
>
> sw_desc.drvdata = qmp;
> sw_desc.fwnode = dev->fwnode;
> @@ -3374,10 +3474,23 @@ static int qmp_combo_typec_switch_register(struct qmp_combo *qmp)
> return PTR_ERR(qmp->sw);
> }
>
> - return devm_add_action_or_reset(dev, qmp_combo_typec_unregister, qmp);
> + ret = devm_add_action_or_reset(dev, qmp_combo_typec_switch_unregister, qmp);
> + if (ret)
> + return ret;
> +
> + mux_desc.drvdata = qmp;
> + mux_desc.fwnode = dev->fwnode;
> + mux_desc.set = qmp_combo_typec_mux_set;
> + qmp->mux = typec_mux_register(dev, &mux_desc);
> + if (IS_ERR(qmp->mux)) {
> + dev_err(dev, "Unable to register typec mux: %pe\n", qmp->mux);
> + return PTR_ERR(qmp->mux);
> + }
> +
> + return devm_add_action_or_reset(dev, qmp_combo_typec_mux_unregister, qmp);
> }
> #else
> -static int qmp_combo_typec_switch_register(struct qmp_combo *qmp)
> +static int qmp_combo_typec_register(struct qmp_combo *qmp)
> {
> return 0;
> }
> @@ -3609,7 +3722,7 @@ static int qmp_combo_probe(struct platform_device *pdev)
> if (ret)
> goto err_node_put;
>
> - ret = qmp_combo_typec_switch_register(qmp);
> + ret = qmp_combo_typec_register(qmp);
> if (ret)
> goto err_node_put;
>
>
> --
> 2.34.1
>
--
With best wishes
Dmitry
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