clk: qcom: gdsc: Add support to update GDSC transition delay

[ Upstream commit 4e7c4d3652f96f41179aab3ff53025c7a550d689 ]

GDSCs have multiple transition delays which are used for the GDSC FSM
states. Older targets/designs required these values to be updated from
gdsc code to certain default values for the FSM state to work as
expected. But on the newer targets/designs the values updated from the
GDSC driver can hamper the FSM state to not work as expected.

On SC7180 we observe black screens because the gdsc is being
enabled/disabled very rapidly and the GDSC FSM state does not work as
expected. This is due to the fact that the GDSC reset value is being
updated from SW.

Thus add support to update the transition delay from the clock
controller gdscs as required.

Fixes: 45dd0e55317cc ("clk: qcom: Add support for GDSCs)
Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lore.kernel.org/r/20220223185606.3941-1-tdas@codeaurora.org
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index 4ece326..cf23cfd 100644 (file)
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2015, 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2015, 2017-2018, 2022, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/bitops.h>
@@ -34,9 +34,14 @@
 #define CFG_GDSCR_OFFSET               0x4
 
 /* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
-#define EN_REST_WAIT_VAL       (0x2 << 20)
-#define EN_FEW_WAIT_VAL                (0x8 << 16)
-#define CLK_DIS_WAIT_VAL       (0x2 << 12)
+#define EN_REST_WAIT_VAL       0x2
+#define EN_FEW_WAIT_VAL                0x8
+#define CLK_DIS_WAIT_VAL       0x2
+
+/* Transition delay shifts */
+#define EN_REST_WAIT_SHIFT     20
+#define EN_FEW_WAIT_SHIFT      16
+#define CLK_DIS_WAIT_SHIFT     12
 
 #define RETAIN_MEM             BIT(14)
 #define RETAIN_PERIPH          BIT(13)
@@ -341,7 +346,18 @@ static int gdsc_init(struct gdsc *sc)
         */
        mask = HW_CONTROL_MASK | SW_OVERRIDE_MASK |
               EN_REST_WAIT_MASK | EN_FEW_WAIT_MASK | CLK_DIS_WAIT_MASK;
-       val = EN_REST_WAIT_VAL | EN_FEW_WAIT_VAL | CLK_DIS_WAIT_VAL;
+
+       if (!sc->en_rest_wait_val)
+               sc->en_rest_wait_val = EN_REST_WAIT_VAL;
+       if (!sc->en_few_wait_val)
+               sc->en_few_wait_val = EN_FEW_WAIT_VAL;
+       if (!sc->clk_dis_wait_val)
+               sc->clk_dis_wait_val = CLK_DIS_WAIT_VAL;
+
+       val = sc->en_rest_wait_val << EN_REST_WAIT_SHIFT |
+               sc->en_few_wait_val << EN_FEW_WAIT_SHIFT |
+               sc->clk_dis_wait_val << CLK_DIS_WAIT_SHIFT;
+
        ret = regmap_update_bits(sc->regmap, sc->gdscr, mask, val);
        if (ret)
                return ret;

diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 5bb396b..762f1b5 100644 (file)
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * Copyright (c) 2015, 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2015, 2017-2018, 2022, The Linux Foundation. All rights reserved.
  */
 
 #ifndef __QCOM_GDSC_H__
@@ -22,6 +22,9 @@ struct reset_controller_dev;
  * @cxcs: offsets of branch registers to toggle mem/periph bits in
  * @cxc_count: number of @cxcs
  * @pwrsts: Possible powerdomain power states
+ * @en_rest_wait_val: transition delay value for receiving enr ack signal
+ * @en_few_wait_val: transition delay value for receiving enf ack signal
+ * @clk_dis_wait_val: transition delay value for halting clock
  * @resets: ids of resets associated with this gdsc
  * @reset_count: number of @resets
  * @rcdev: reset controller
@@ -35,6 +38,9 @@ struct gdsc {
        unsigned int                    clamp_io_ctrl;
        unsigned int                    *cxcs;
        unsigned int                    cxc_count;
+       unsigned int                    en_rest_wait_val;
+       unsigned int                    en_few_wait_val;
+       unsigned int                    clk_dis_wait_val;
        const u8                        pwrsts;
 /* Powerdomain allowable state bitfields */
 #define PWRSTS_OFF             BIT(0)