OMAP3+: Introduce generic logic for OMAP voltage controller

OMAP Voltage controller is used to generically talk to
PMICs on OMAP3,4,5 over I2C_SR. Instead of replicating code
in multiple SoC code, introduce a common voltage controller
logic which can be re-used from elsewhere.

With this change, we replace setup_sri2c with omap_vc_init which
has the same functionality, and replace the voltage scale
replication in do_scale_vcore and do_scale_tps62361 with
omap_vc_bypass_send_value. omap_vc_bypass_send_value can also
now be used with any configuration of PMIC.

NOTE: Voltage controller controlling I2C_SR is a write-only data
path, so no register read operation can be implemented.

Reported-by: Isabelle Gros <i-gros@ti.com>
Reported-by: Jerome Angeloni <j-angeloni@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>

1 files changed, 138 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/omap-common/vc.c b/arch/arm/cpu/armv7/omap-common/vc.c
new file mode 100644
index 0000000..a045b77
--- /dev/null
+++ b/arch/arm/cpu/armv7/omap-common/vc.c
@@ -0,0 +1,138 @@
+/*
+ * Voltage Controller implementation for OMAP
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *	Nishanth Menon
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <asm/omap_common.h>
+#include <asm/arch/sys_proto.h>
+
+/*
+ * Define Master code if there are multiple masters on the I2C_SR bus.
+ * Normally not required
+ */
+#ifndef CONFIG_OMAP_VC_I2C_HS_MCODE
+#define CONFIG_OMAP_VC_I2C_HS_MCODE 0x0
+#endif
+
+/* Register defines and masks for VC IP Block */
+/* PRM_VC_CFG_I2C_MODE */
+#define PRM_VC_CFG_I2C_MODE_DFILTEREN_BIT	(0x1 << 6)
+#define PRM_VC_CFG_I2C_MODE_SRMODEEN_BIT	(0x1 << 4)
+#define PRM_VC_CFG_I2C_MODE_HSMODEEN_BIT	(0x1 << 3)
+#define PRM_VC_CFG_I2C_MODE_HSMCODE_SHIFT	0x0
+#define PRM_VC_CFG_I2C_MODE_HSMCODE_MASK	0x3
+
+/* PRM_VC_CFG_I2C_CLK */
+#define PRM_VC_CFG_I2C_CLK_HSCLL_SHIFT		24
+#define PRM_VC_CFG_I2C_CLK_HSCLL_MASK		0xFF
+#define PRM_VC_CFG_I2C_CLK_HSCLH_SHIFT		16
+#define PRM_VC_CFG_I2C_CLK_HSCLH_MASK		0xFF
+#define PRM_VC_CFG_I2C_CLK_SCLH_SHIFT		0
+#define PRM_VC_CFG_I2C_CLK_SCLH_MASK		0xFF
+#define PRM_VC_CFG_I2C_CLK_SCLL_SHIFT		8
+#define PRM_VC_CFG_I2C_CLK_SCLL_MASK		(0xFF << 8)
+
+/* PRM_VC_VAL_BYPASS */
+#define PRM_VC_VAL_BYPASS_VALID_BIT		(0x1 << 24)
+#define PRM_VC_VAL_BYPASS_SLAVEADDR_SHIFT	0
+#define PRM_VC_VAL_BYPASS_SLAVEADDR_MASK	0x7F
+#define PRM_VC_VAL_BYPASS_REGADDR_SHIFT		8
+#define PRM_VC_VAL_BYPASS_REGADDR_MASK		0xFF
+#define PRM_VC_VAL_BYPASS_DATA_SHIFT		16
+#define PRM_VC_VAL_BYPASS_DATA_MASK		0xFF
+
+/**
+ * omap_vc_init() - Initialization for Voltage controller
+ * @speed_khz: I2C buspeed in KHz
+ */
+void omap_vc_init(u16 speed_khz)
+{
+	u32 val;
+	u32 sys_clk_khz, cycles_hi, cycles_low;
+
+	sys_clk_khz = get_sys_clk_freq() / 1000;
+
+	if (speed_khz > 400) {
+		puts("higher speed requested - throttle to 400Khz\n");
+		speed_khz = 400;
+	}
+
+	/*
+	 * Setup the dedicated I2C controller for Voltage Control
+	 * I2C clk - high period 40% low period 60%
+	 */
+	speed_khz /= 10;
+	cycles_hi = sys_clk_khz * 4 / speed_khz;
+	cycles_low = sys_clk_khz * 6 / speed_khz;
+	/* values to be set in register - less by 5 & 7 respectively */
+	cycles_hi -= 5;
+	cycles_low -= 7;
+	val = (cycles_hi << PRM_VC_CFG_I2C_CLK_SCLH_SHIFT) |
+	       (cycles_low << PRM_VC_CFG_I2C_CLK_SCLL_SHIFT);
+	writel(val, &prcm->prm_vc_cfg_i2c_clk);
+
+	val = CONFIG_OMAP_VC_I2C_HS_MCODE <<
+		PRM_VC_CFG_I2C_MODE_HSMCODE_SHIFT;
+	/* No HS mode for now */
+	val &= ~PRM_VC_CFG_I2C_MODE_HSMODEEN_BIT;
+	writel(val, &prcm->prm_vc_cfg_i2c_mode);
+}
+
+/**
+ * omap_vc_bypass_send_value() - Send a data using VC Bypass command
+ * @sa:		7 bit I2C slave address of the PMIC
+ * @reg_addr:	I2C register address(8 bit) address in PMIC
+ * @reg_data:	what 8 bit data to write
+ */
+int omap_vc_bypass_send_value(u8 sa, u8 reg_addr, u8 reg_data)
+{
+	/*
+	 * Unfortunately we need to loop here instead of a defined time
+	 * use arbitary large value
+	 */
+	u32 timeout = 0xFFFF;
+	u32 reg_val;
+
+	sa &= PRM_VC_VAL_BYPASS_SLAVEADDR_MASK;
+	reg_addr &= PRM_VC_VAL_BYPASS_REGADDR_MASK;
+	reg_data &= PRM_VC_VAL_BYPASS_DATA_MASK;
+
+	/* program VC to send data */
+	reg_val = sa << PRM_VC_VAL_BYPASS_SLAVEADDR_SHIFT |
+	    reg_addr << PRM_VC_VAL_BYPASS_REGADDR_SHIFT |
+	    reg_data << PRM_VC_VAL_BYPASS_DATA_SHIFT;
+	writel(reg_val, &prcm->prm_vc_val_bypass);
+
+	/* Signal VC to send data */
+	writel(reg_val | PRM_VC_VAL_BYPASS_VALID_BIT, &prcm->prm_vc_val_bypass);
+
+	/* Wait on VC to complete transmission */
+	do {
+		reg_val = readl(&prcm->prm_vc_val_bypass) &
+				PRM_VC_VAL_BYPASS_VALID_BIT;
+		if (!reg_val)
+			break;
+
+		sdelay(100);
+	} while (--timeout);
+
+	/* Optional: cleanup PRM_IRQSTATUS_Ax */
+	/* In case we can do something about it in future.. */
+	if (!timeout)
+		return -1;
+
+	/* All good.. */
+	return 0;
+}