[PATCH v2 2/3] usb: typec: tcpci: Add support to report vSafe0V

[Badhri Jagan Sridharan]

This change adds vbus_vsafe0v which when set, makes TCPM
query for VSAFE0V by assigning the tcpc.is_vbus_vsafe0v callback.
Also enables ALERT.ExtendedStatus which is triggered when
status of EXTENDED_STATUS.vSafe0V changes.
EXTENDED_STATUS.vSafe0V is set when vbus is at vSafe0V and
cleared otherwise.

Signed-off-by: Badhri Jagan Sridharan <bad...@google.com>
---
Changes since v1:
- Removed logic for checking TCPC_POWER_STATUS_MASK reg
  read in the irq handler. Sending that as a separate patch.
---
 drivers/usb/typec/tcpm/tcpci.c | 39 +++++++++++++++++++++++++++++-----
 drivers/usb/typec/tcpm/tcpci.h |  6 ++++++
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index 12d983a75510..f938d9876ce9 100644
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -402,6 +402,19 @@ static int tcpci_get_vbus(struct tcpc_dev *tcpc)
        return !!(reg & TCPC_POWER_STATUS_VBUS_PRES);
 }
 
+static bool tcpci_is_vbus_vsafe0v(struct tcpc_dev *tcpc)
+{
+       struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
+       unsigned int reg;
+       int ret;
+
+       ret = regmap_read(tcpci->regmap, TCPC_EXTENDED_STATUS, &reg);
+       if (ret < 0)
+               return false;
+
+       return !!(reg & TCPC_EXTENDED_STATUS_VSAFE0V);
+}
+
 static int tcpci_set_vbus(struct tcpc_dev *tcpc, bool source, bool sink)
 {
        struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
@@ -554,12 +567,22 @@ static int tcpci_init(struct tcpc_dev *tcpc)
                TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_CC_STATUS;
        if (tcpci->controls_vbus)
                reg |= TCPC_ALERT_POWER_STATUS;
+       /* Enable VSAFE0V status interrupt when detecting VSAFE0V is supported 
*/
+       if (tcpci->data->vbus_vsafe0v) {
+               reg |= TCPC_ALERT_EXTENDED_STATUS;
+               ret = regmap_write(tcpci->regmap, TCPC_EXTENDED_STATUS_MASK,
+                                  TCPC_EXTENDED_STATUS_VSAFE0V);
+               if (ret < 0)
+                       return ret;
+       }
        return tcpci_write16(tcpci, TCPC_ALERT_MASK, reg);
 }
 
 irqreturn_t tcpci_irq(struct tcpci *tcpci)
 {
        u16 status;
+       int ret;
+       unsigned int raw;
 
        tcpci_read16(tcpci, TCPC_ALERT, &status);
 
@@ -575,15 +598,12 @@ irqreturn_t tcpci_irq(struct tcpci *tcpci)
                tcpm_cc_change(tcpci->port);
 
        if (status & TCPC_ALERT_POWER_STATUS) {
-               unsigned int reg;
-
-               regmap_read(tcpci->regmap, TCPC_POWER_STATUS_MASK, &reg);
-
+               regmap_read(tcpci->regmap, TCPC_POWER_STATUS_MASK, &raw);
                /*
                 * If power status mask has been reset, then the TCPC
                 * has reset.
                 */
-               if (reg == 0xff)
+               if (raw == 0xff)
                        tcpm_tcpc_reset(tcpci->port);
                else
                        tcpm_vbus_change(tcpci->port);
@@ -622,6 +642,12 @@ irqreturn_t tcpci_irq(struct tcpci *tcpci)
                tcpm_pd_receive(tcpci->port, &msg);
        }
 
+       if (status & TCPC_ALERT_EXTENDED_STATUS) {
+               ret = regmap_read(tcpci->regmap, TCPC_EXTENDED_STATUS, &raw);
+               if (!ret && (raw & TCPC_EXTENDED_STATUS_VSAFE0V))
+                       tcpm_vbus_change(tcpci->port);
+       }
+
        if (status & TCPC_ALERT_RX_HARD_RST)
                tcpm_pd_hard_reset(tcpci->port);
 
@@ -699,6 +725,9 @@ struct tcpci *tcpci_register_port(struct device *dev, 
struct tcpci_data *data)
                        tcpci_set_auto_vbus_discharge_threshold;
        }
 
+       if (tcpci->data->vbus_vsafe0v)
+               tcpci->tcpc.is_vbus_vsafe0v = tcpci_is_vbus_vsafe0v;
+
        err = tcpci_parse_config(tcpci);
        if (err < 0)
                return ERR_PTR(err);
diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h
index 3fe313655f0c..116a69c85e38 100644
--- a/drivers/usb/typec/tcpm/tcpci.h
+++ b/drivers/usb/typec/tcpm/tcpci.h
@@ -49,6 +49,9 @@
 #define TCPC_TCPC_CTRL_ORIENTATION     BIT(0)
 #define TCPC_TCPC_CTRL_BIST_TM         BIT(1)
 
+#define TCPC_EXTENDED_STATUS           0x20
+#define TCPC_EXTENDED_STATUS_VSAFE0V   BIT(0)
+
 #define TCPC_ROLE_CTRL                 0x1a
 #define TCPC_ROLE_CTRL_DRP             BIT(6)
 #define TCPC_ROLE_CTRL_RP_VAL_SHIFT    4
@@ -155,11 +158,14 @@ struct tcpci;
  *             is sourcing vbus.
  * @auto_discharge_disconnect:
  *             Optional; Enables TCPC to autonously discharge vbus on 
disconnect.
+ * @vbus_vsafe0v:
+ *             optional; Set when TCPC can detect whether vbus is at VSAFE0V.
  */
 struct tcpci_data {
        struct regmap *regmap;
        unsigned char TX_BUF_BYTE_x_hidden:1;
        unsigned char auto_discharge_disconnect:1;
+       unsigned char vbus_vsafe0v:1;
 
        int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
        int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,
-- 
2.29.2.576.ga3fc446d84-goog