mfd: syscon: Add atmel-smc registers definition

Atmel AT91 SoCs have a memory range reserved for SMC (Static Memory
Controller) configuration.
Expose those registers so that drivers can make use of the smc syscon
declared in at91 DTs.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

include/linux/mfd/syscon/atmel-smc.h

@@ -0,0 +1,173 @@
+/*
+ * Atmel SMC (Static Memory Controller) register offsets and bit definitions.
+ *
+ * Copyright (C) 2014 Atmel
+ * Copyright (C) 2014 Free Electrons
+ *
+ * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_MFD_SYSCON_ATMEL_SMC_H_
+#define _LINUX_MFD_SYSCON_ATMEL_SMC_H_
+
+#include <linux/kernel.h>
+#include <linux/regmap.h>
+
+#define AT91SAM9_SMC_GENERIC		0x00
+#define AT91SAM9_SMC_GENERIC_BLK_SZ	0x10
+
+#define SAMA5_SMC_GENERIC		0x600
+#define SAMA5_SMC_GENERIC_BLK_SZ	0x14
+
+#define AT91SAM9_SMC_SETUP(o)		((o) + 0x00)
+#define AT91SAM9_SMC_NWESETUP(x)	(x)
+#define AT91SAM9_SMC_NCS_WRSETUP(x)	((x) << 8)
+#define AT91SAM9_SMC_NRDSETUP(x)	((x) << 16)
+#define AT91SAM9_SMC_NCS_NRDSETUP(x)	((x) << 24)
+
+#define AT91SAM9_SMC_PULSE(o)		((o) + 0x04)
+#define AT91SAM9_SMC_NWEPULSE(x)	(x)
+#define AT91SAM9_SMC_NCS_WRPULSE(x)	((x) << 8)
+#define AT91SAM9_SMC_NRDPULSE(x)	((x) << 16)
+#define AT91SAM9_SMC_NCS_NRDPULSE(x)	((x) << 24)
+
+#define AT91SAM9_SMC_CYCLE(o)		((o) + 0x08)
+#define AT91SAM9_SMC_NWECYCLE(x)	(x)
+#define AT91SAM9_SMC_NRDCYCLE(x)	((x) << 16)
+
+#define AT91SAM9_SMC_MODE(o)		((o) + 0x0c)
+#define SAMA5_SMC_MODE(o)		((o) + 0x10)
+#define AT91_SMC_READMODE		BIT(0)
+#define AT91_SMC_READMODE_NCS		(0 << 0)
+#define AT91_SMC_READMODE_NRD		(1 << 0)
+#define AT91_SMC_WRITEMODE		BIT(1)
+#define AT91_SMC_WRITEMODE_NCS		(0 << 1)
+#define AT91_SMC_WRITEMODE_NWE		(1 << 1)
+#define AT91_SMC_EXNWMODE		GENMASK(5, 4)
+#define AT91_SMC_EXNWMODE_DISABLE	(0 << 4)
+#define AT91_SMC_EXNWMODE_FROZEN	(2 << 4)
+#define AT91_SMC_EXNWMODE_READY		(3 << 4)
+#define AT91_SMC_BAT			BIT(8)
+#define AT91_SMC_BAT_SELECT		(0 << 8)
+#define AT91_SMC_BAT_WRITE		(1 << 8)
+#define AT91_SMC_DBW			GENMASK(13, 12)
+#define AT91_SMC_DBW_8			(0 << 12)
+#define AT91_SMC_DBW_16			(1 << 12)
+#define AT91_SMC_DBW_32			(2 << 12)
+#define AT91_SMC_TDF			GENMASK(19, 16)
+#define AT91_SMC_TDF_(x)		((((x) - 1) << 16) & AT91_SMC_TDF)
+#define AT91_SMC_TDF_MAX		16
+#define AT91_SMC_TDFMODE_OPTIMIZED	BIT(20)
+#define AT91_SMC_PMEN			BIT(24)
+#define AT91_SMC_PS			GENMASK(29, 28)
+#define AT91_SMC_PS_4			(0 << 28)
+#define AT91_SMC_PS_8			(1 << 28)
+#define AT91_SMC_PS_16			(2 << 28)
+#define AT91_SMC_PS_32			(3 << 28)
+
+
+/*
+ * This function converts a setup timing expressed in nanoseconds into an
+ * encoded value that can be written in the SMC_SETUP register.
+ *
+ * The following formula is described in atmel datasheets (section
+ * "SMC Setup Register"):
+ *
+ * setup length = (128* SETUP[5] + SETUP[4:0])
+ *
+ * where setup length is the timing expressed in cycles.
+ */
+static inline u32 at91sam9_smc_setup_ns_to_cycles(unsigned int clk_rate,
+						  u32 timing_ns)
+{
+	u32 clk_period = DIV_ROUND_UP(NSEC_PER_SEC, clk_rate);
+	u32 coded_cycles = 0;
+	u32 cycles;
+
+	cycles = DIV_ROUND_UP(timing_ns, clk_period);
+	if (cycles / 32) {
+		coded_cycles |= 1 << 5;
+		if (cycles < 128)
+			cycles = 0;
+	}
+
+	coded_cycles |= cycles % 32;
+
+	return coded_cycles;
+}
+
+/*
+ * This function converts a pulse timing expressed in nanoseconds into an
+ * encoded value that can be written in the SMC_PULSE register.
+ *
+ * The following formula is described in atmel datasheets (section
+ * "SMC Pulse Register"):
+ *
+ * pulse length = (256* PULSE[6] + PULSE[5:0])
+ *
+ * where pulse length is the timing expressed in cycles.
+ */
+static inline u32 at91sam9_smc_pulse_ns_to_cycles(unsigned int clk_rate,
+						  u32 timing_ns)
+{
+	u32 clk_period = DIV_ROUND_UP(NSEC_PER_SEC, clk_rate);
+	u32 coded_cycles = 0;
+	u32 cycles;
+
+	cycles = DIV_ROUND_UP(timing_ns, clk_period);
+	if (cycles / 64) {
+		coded_cycles |= 1 << 6;
+		if (cycles < 256)
+			cycles = 0;
+	}
+
+	coded_cycles |= cycles % 64;
+
+	return coded_cycles;
+}
+
+/*
+ * This function converts a cycle timing expressed in nanoseconds into an
+ * encoded value that can be written in the SMC_CYCLE register.
+ *
+ * The following formula is described in atmel datasheets (section
+ * "SMC Cycle Register"):
+ *
+ * cycle length = (CYCLE[8:7]*256 + CYCLE[6:0])
+ *
+ * where cycle length is the timing expressed in cycles.
+ */
+static inline u32 at91sam9_smc_cycle_ns_to_cycles(unsigned int clk_rate,
+						  u32 timing_ns)
+{
+	u32 clk_period = DIV_ROUND_UP(NSEC_PER_SEC, clk_rate);
+	u32 coded_cycles = 0;
+	u32 cycles;
+
+	cycles = DIV_ROUND_UP(timing_ns, clk_period);
+	if (cycles / 128) {
+		coded_cycles = cycles / 256;
+		cycles %= 256;
+		if (cycles >= 128) {
+			coded_cycles++;
+			cycles = 0;
+		}
+
+		if (coded_cycles > 0x3) {
+			coded_cycles = 0x3;
+			cycles = 0x7f;
+		}
+
+		coded_cycles <<= 7;
+	}
+
+	coded_cycles |= cycles % 128;
+
+	return coded_cycles;
+}
+
+#endif /* _LINUX_MFD_SYSCON_ATMEL_SMC_H_ */