hwmon: tegra: tsensor: lp0 save/restore configuration

tsensor configuration needs to be saved before lp0 and restored
after lp0 resume else POR values are seen after lp0 resume.
- Config0, Config1 and Config2 registers are saved and restored

bug 851791

Original-Change-Id: I95532d995af4fa71e169209bb1788fc4152290fe
Reviewed-on: http://git-master/r/41819
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>
Tested-by: Bitan Biswas <bbiswas@nvidia.com>
Reviewed-by: Narendra Damahe <ndamahe@nvidia.com>
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>

Rebase-Id: Raceac7154fc86486f2726cdd13637d7e8d1e6828

1 files changed, 68 insertions, 3 deletions

diff --git a/drivers/hwmon/tegra-tsensor.c b/drivers/hwmon/tegra-tsensor.c
index 7e0f002fc4dd..ae274474e1a7 100644
--- a/drivers/hwmon/tegra-tsensor.c
+++ b/drivers/hwmon/tegra-tsensor.c
@@ -174,6 +174,10 @@ struct tegra_tsensor_data {
 	int sw_intr_temp;
 	int hysteresis;
 	unsigned int ts_state_saved[TSENSOR_COUNT];
+	/* save configuration before suspend and restore after resume */
+	unsigned int config0[TSENSOR_COUNT];
+	unsigned int config1[TSENSOR_COUNT];
+	unsigned int config2[TSENSOR_COUNT];
 };
 
 enum {
@@ -1623,6 +1627,59 @@ static int __devexit tegra_tsensor_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void dump_a_tsensor_reg(struct tegra_tsensor_data *data,
+	unsigned int addr)
+{
+	dev_dbg(data->hwmon_dev, "\n tsensor[%d][0x%x]: 0x%x ", (addr >> 16),
+		addr & 0xFFFF, tsensor_readl(data, addr));
+}
+
+static void dump_tsensor_regs(struct tegra_tsensor_data *data)
+{
+	int i;
+	for (i = 0; i < TSENSOR_COUNT; i++) {
+		/* if STOP bit is set skip this check */
+		dump_a_tsensor_reg(data, ((i << 16) | SENSOR_CFG0));
+		dump_a_tsensor_reg(data, ((i << 16) | SENSOR_CFG1));
+		dump_a_tsensor_reg(data, ((i << 16) | SENSOR_CFG2));
+		dump_a_tsensor_reg(data, ((i << 16) | SENSOR_STATUS0));
+		dump_a_tsensor_reg(data, ((i << 16) | SENSOR_TS_STATUS1));
+		dump_a_tsensor_reg(data, ((i << 16) | SENSOR_TS_STATUS2));
+		dump_a_tsensor_reg(data, ((i << 16) | 0x0));
+		dump_a_tsensor_reg(data, ((i << 16) | 0x44));
+		dump_a_tsensor_reg(data, ((i << 16) | 0x50));
+		dump_a_tsensor_reg(data, ((i << 16) | 0x54));
+		dump_a_tsensor_reg(data, ((i << 16) | 0x64));
+		dump_a_tsensor_reg(data, ((i << 16) | 0x68));
+	}
+}
+
+static void save_tsensor_regs(struct tegra_tsensor_data *data)
+{
+	int i;
+	for (i = 0; i < TSENSOR_COUNT; i++) {
+		data->config0[i] = tsensor_readl(data,
+			((i << 16) | SENSOR_CFG0));
+		data->config1[i] = tsensor_readl(data,
+			((i << 16) | SENSOR_CFG1));
+		data->config2[i] = tsensor_readl(data,
+			((i << 16) | SENSOR_CFG2));
+	}
+}
+
+static void restore_tsensor_regs(struct tegra_tsensor_data *data)
+{
+	int i;
+	for (i = 0; i < TSENSOR_COUNT; i++) {
+		tsensor_writel(data, data->config0[i],
+			((i << 16) | SENSOR_CFG0));
+		tsensor_writel(data, data->config1[i],
+			((i << 16) | SENSOR_CFG1));
+		tsensor_writel(data, data->config2[i],
+			((i << 16) | SENSOR_CFG2));
+	}
+}
+
 #ifdef CONFIG_PM
 static int tsensor_suspend(struct platform_device *pdev,
 	pm_message_t state)
@@ -1630,13 +1687,16 @@ static int tsensor_suspend(struct platform_device *pdev,
 	struct tegra_tsensor_data *data = platform_get_drvdata(pdev);
 	unsigned int config0;
 	int i;
+	dev_dbg(data->hwmon_dev, "\n tsensor before suspend reg dump: ");
+	dump_tsensor_regs(data);
 	/* set STOP bit, else OVERFLOW interrupt seen in LP1 */
 	for (i = 0; i < TSENSOR_COUNT; i++) {
 		config0 = tsensor_readl(data, ((i << 16) | SENSOR_CFG0));
 		config0 |= (1 << SENSOR_CFG0_STOP_SHIFT);
 		tsensor_writel(data, config0, ((i << 16) | SENSOR_CFG0));
 	}
-	/* TBD: check anything else that could be needed for suspend */
+	/* save current settings before suspend, when STOP bit is set */
+	save_tsensor_regs(data);
 	tsensor_clk_enable(data, false);
 
 	return 0;
@@ -1647,14 +1707,19 @@ static int tsensor_resume(struct platform_device *pdev)
 	struct tegra_tsensor_data *data = platform_get_drvdata(pdev);
 	unsigned int config0;
 	int i;
-	/* TBD: check anything else that could be needed for resume */
 	tsensor_clk_enable(data, true);
-	/* clear STOP bit */
+	/* restore current settings before suspend, no need
+	 * to clear STOP bit */
+	restore_tsensor_regs(data);
+	/* clear STOP bit, after restoring regs */
 	for (i = 0; i < TSENSOR_COUNT; i++) {
 		config0 = tsensor_readl(data, ((i << 16) | SENSOR_CFG0));
 		config0 &= ~(1 << SENSOR_CFG0_STOP_SHIFT);
 		tsensor_writel(data, config0, ((i << 16) | SENSOR_CFG0));
 	}
+	msleep(1);
+	dev_dbg(data->hwmon_dev, "\n tsensor after resume reg dump: ");
+	dump_tsensor_regs(data);
 
 	return 0;
 }