iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted

vl53l0x_read_raw() starts a single-shot ranging measurement and reads
back the result. Once the triggered buffer is enabled the sensor runs in
continuous mode and its data-ready interrupt is routed to the trigger,
so a concurrent in_distance_raw read disturbs the streaming setup and
never gets its completion, returning -ETIMEDOUT.

The original submission claimed direct mode here, but it was dropped
during review because the driver had no buffer support at the time [1].
Continuous (buffered) mode was later added without restoring the
claim [2], reintroducing the conflict.

Reject direct reads while buffered capture is active by claiming direct
mode around the measurement, as the vl53l1x sibling already does.

Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support")
Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1]
Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2]
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/include/soc/tegra/flowctrl.h b/include/soc/tegra/flowctrl.h
new file mode 100644
index 000000000..2a60bd493
--- /dev/null
+++ b/include/soc/tegra/flowctrl.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Functions and macros to control the flowcontroller
+ *
+ * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
+ */
+
+#ifndef __SOC_TEGRA_FLOWCTRL_H__
+#define __SOC_TEGRA_FLOWCTRL_H__
+
+#define FLOW_CTRL_HALT_CPU0_EVENTS	0x0
+#define FLOW_CTRL_WAITEVENT		(2 << 29)
+#define FLOW_CTRL_WAIT_FOR_INTERRUPT	(4 << 29)
+#define FLOW_CTRL_JTAG_RESUME		(1 << 28)
+#define FLOW_CTRL_SCLK_RESUME		(1 << 27)
+#define FLOW_CTRL_HALT_CPU_IRQ		(1 << 10)
+#define	FLOW_CTRL_HALT_CPU_FIQ		(1 << 8)
+#define FLOW_CTRL_HALT_LIC_IRQ		(1 << 11)
+#define FLOW_CTRL_HALT_LIC_FIQ		(1 << 10)
+#define FLOW_CTRL_HALT_GIC_IRQ		(1 << 9)
+#define FLOW_CTRL_HALT_GIC_FIQ		(1 << 8)
+#define FLOW_CTRL_CPU0_CSR		0x8
+#define	FLOW_CTRL_CSR_INTR_FLAG		(1 << 15)
+#define FLOW_CTRL_CSR_EVENT_FLAG	(1 << 14)
+#define FLOW_CTRL_CSR_ENABLE_EXT_CRAIL	(1 << 13)
+#define FLOW_CTRL_CSR_ENABLE_EXT_NCPU	(1 << 12)
+#define FLOW_CTRL_CSR_ENABLE_EXT_MASK ( \
+		FLOW_CTRL_CSR_ENABLE_EXT_NCPU | \
+		FLOW_CTRL_CSR_ENABLE_EXT_CRAIL)
+#define FLOW_CTRL_CSR_ENABLE		(1 << 0)
+#define FLOW_CTRL_HALT_CPU1_EVENTS	0x14
+#define FLOW_CTRL_CPU1_CSR		0x18
+
+#define TEGRA20_FLOW_CTRL_CSR_WFE_CPU0		(1 << 4)
+#define TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP	(3 << 4)
+#define TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP	0
+
+#define TEGRA30_FLOW_CTRL_CSR_WFI_CPU0		(1 << 8)
+#define TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP	(0xF << 4)
+#define TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP	(0xF << 8)
+
+#ifndef __ASSEMBLER__
+#ifdef CONFIG_SOC_TEGRA_FLOWCTRL
+u32 flowctrl_read_cpu_csr(unsigned int cpuid);
+void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value);
+void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value);
+
+void flowctrl_cpu_suspend_enter(unsigned int cpuid);
+void flowctrl_cpu_suspend_exit(unsigned int cpuid);
+#else
+static inline u32 flowctrl_read_cpu_csr(unsigned int cpuid)
+{
+	return 0;
+}
+
+static inline void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value)
+{
+}
+
+static inline void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value) {}
+
+static inline void flowctrl_cpu_suspend_enter(unsigned int cpuid)
+{
+}
+
+static inline void flowctrl_cpu_suspend_exit(unsigned int cpuid)
+{
+}
+#endif /* CONFIG_SOC_TEGRA_FLOWCTRL */
+#endif /* __ASSEMBLER__ */
+#endif /* __SOC_TEGRA_FLOWCTRL_H__ */