i.MX28: Add LRADC init to i.MX28 SPL

This code is part of battery boot support for i.MX28.

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>

arch/arm/cpu/arm926ejs/mx28/Makefile

@@ -28,7 +28,7 @@ LIB	= $(obj)lib$(SOC).o
 COBJS	= clock.o mx28.o iomux.o timer.o
 
 ifdef	CONFIG_SPL_BUILD
-COBJS	+= spl_boot.o spl_mem_init.o spl_power_init.o
+COBJS	+= spl_boot.o spl_lradc_init.o spl_mem_init.o spl_power_init.o
 endif
 
 SRCS	:= $(START:.o=.S) $(COBJS:.o=.c)

arch/arm/cpu/arm926ejs/mx28/mx28_init.h

@@ -39,4 +39,7 @@ static inline void mx28_power_wait_pswitch(void) { }
 void mx28_mem_init(void);
 uint32_t mx28_mem_get_size(void);
 
+void mx28_lradc_init(void);
+void mx28_lradc_enable_batt_measurement(void);
+
 #endif	/* __M28_INIT_H__ */

arch/arm/cpu/arm926ejs/mx28/spl_lradc_init.c

@@ -0,0 +1,86 @@
+/*
+ * Freescale i.MX28 Battery measurement init
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <config.h>
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+
+#include "mx28_init.h"
+
+void mx28_lradc_init(void)
+{
+	struct mx28_lradc_regs *regs = (struct mx28_lradc_regs *)MXS_LRADC_BASE;
+
+	writel(LRADC_CTRL0_SFTRST, &regs->hw_lradc_ctrl0_clr);
+	writel(LRADC_CTRL0_CLKGATE, &regs->hw_lradc_ctrl0_clr);
+	writel(LRADC_CTRL0_ONCHIP_GROUNDREF, &regs->hw_lradc_ctrl0_clr);
+
+	clrsetbits_le32(&regs->hw_lradc_ctrl3,
+			LRADC_CTRL3_CYCLE_TIME_MASK,
+			LRADC_CTRL3_CYCLE_TIME_6MHZ);
+
+	clrsetbits_le32(&regs->hw_lradc_ctrl4,
+			LRADC_CTRL4_LRADC7SELECT_MASK |
+			LRADC_CTRL4_LRADC6SELECT_MASK,
+			LRADC_CTRL4_LRADC7SELECT_CHANNEL7 |
+			LRADC_CTRL4_LRADC6SELECT_CHANNEL10);
+}
+
+void mx28_lradc_enable_batt_measurement(void)
+{
+	struct mx28_lradc_regs *regs = (struct mx28_lradc_regs *)MXS_LRADC_BASE;
+
+	/* Check if the channel is present at all. */
+	if (!(readl(&regs->hw_lradc_status) & LRADC_STATUS_CHANNEL7_PRESENT))
+		return;
+
+	writel(LRADC_CTRL1_LRADC7_IRQ_EN, &regs->hw_lradc_ctrl1_clr);
+	writel(LRADC_CTRL1_LRADC7_IRQ, &regs->hw_lradc_ctrl1_clr);
+
+	clrsetbits_le32(&regs->hw_lradc_conversion,
+			LRADC_CONVERSION_SCALE_FACTOR_MASK,
+			LRADC_CONVERSION_SCALE_FACTOR_LI_ION);
+	writel(LRADC_CONVERSION_AUTOMATIC, &regs->hw_lradc_conversion_set);
+
+	/* Configure the channel. */
+	writel((1 << 7) << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET,
+		&regs->hw_lradc_ctrl2_clr);
+	writel(0xffffffff, &regs->hw_lradc_ch7_clr);
+	clrbits_le32(&regs->hw_lradc_ch7, LRADC_CH_NUM_SAMPLES_MASK);
+	writel(LRADC_CH_ACCUMULATE, &regs->hw_lradc_ch7_clr);
+
+	/* Schedule the channel. */
+	writel(1 << 7, &regs->hw_lradc_ctrl0_set);
+
+	/* Start the channel sampling. */
+	writel(((1 << 7) << LRADC_DELAY_TRIGGER_LRADCS_OFFSET) |
+		((1 << 3) << LRADC_DELAY_TRIGGER_DELAYS_OFFSET) |
+		100, &regs->hw_lradc_delay3);
+
+	writel(0xffffffff, &regs->hw_lradc_ch7_clr);
+
+	writel(LRADC_DELAY_KICK, &regs->hw_lradc_delay3_set);
+}

arch/arm/cpu/arm926ejs/mx28/spl_power_init.c

@@ -883,6 +883,13 @@ void mx28_power_set_vddd(uint32_t new_target, uint32_t new_brownout)
 			new_brownout << POWER_VDDDCTRL_BO_OFFSET_OFFSET);
 }
 
+void mx28_setup_batt_detect(void)
+{
+	mx28_lradc_init();
+	mx28_lradc_enable_batt_measurement();
+	early_delay(10);
+}
+
 void mx28_power_init(void)
 {
 	struct mx28_power_regs *power_regs =
@@ -892,6 +899,9 @@ void mx28_power_init(void)
 	mx28_power_clear_auto_restart();
 	mx28_power_set_linreg();
 	mx28_power_setup_5v_detect();
+
+	mx28_setup_batt_detect();
+
 	mx28_power_configure_power_source();
 	mx28_enable_output_rail_protection();