Date:	Mon, 2 May 2016 17:47:11 +0530
From:	Laxman Dewangan <ldewangan@...dia.com>
To:	<swarren@...dotorg.org>, <linus.walleij@...aro.org>,
	<gnurou@...il.com>, <robh+dt@...nel.org>, <mark.rutland@....com>,
	<jonathanh@...dia.com>, <thierry.reding@...il.com>
CC:	<linux-tegra@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
	Laxman Dewangan <ldewangan@...dia.com>
Subject: [PATCH 3/6] soc/tegra: pmc: Add support for IO pads power state and voltage

The IO pins of Tegra SoCs are grouped for common control of IO
interface like setting voltage signal levels and power state of
the interface. The group is generally referred as IO pads. The
power state and voltage control of IO pins can be done at IO pads
level.

Tegra generation SoC supports the power down of IO pads when it
is not used even in the active state of system. This saves power
from that IO interface.

Tegra generation SoC supports multiple voltage level in IO pins for
interfacing on some of pads. Till Tegra124, the IO rail voltage was
detected automatically and IO pads power voltage level sets accordingly.
But from Tegra210, it is required to program by SW explicitly.

Add support to set the power states and voltage level of the IO pads
from client driver. The implementation for the APIs are in generic
which is applicable for all generation os Tegra SoC.

IO pads ID and information of bit field for power state and voltage
level controls are added for Tegra210.

Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>

---
Changes from V1:
This is reworked on earlier path to have separation between IO rails and
io pads and add power state and voltage control APIs in single call.
---
 drivers/soc/tegra/pmc.c | 182 +++++++++++++++++++++++++++++++++++++++++++++++-
 include/soc/tegra/pmc.h |  87 +++++++++++++++++++++++
 2 files changed, 268 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index fc4f7b2..b3be4b9 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -76,6 +76,10 @@
 
 #define PMC_SCRATCH41			0x140
 
+/* Power detect for pad voltage */
+#define PMC_PWR_DET			0x48
+#define PMC_PWR_DET_VAL			0xe4
+
 #define PMC_SENSOR_CTRL			0x1b0
 #define PMC_SENSOR_CTRL_SCRATCH_WRITE	BIT(2)
 #define PMC_SENSOR_CTRL_ENABLE_RST	BIT(1)
@@ -115,12 +119,19 @@ struct tegra_powergate {
 	unsigned int num_resets;
 };
 
+struct tegra_io_pads_control {
+	int pad_id;
+	int dpd_bit_pos;
+	int pwr_val_pos;
+};
+
 struct tegra_pmc_soc {
 	unsigned int num_powergates;
 	const char *const *powergates;
 	unsigned int num_cpu_powergates;
 	const u8 *cpu_powergates;
-
+	const struct tegra_io_pads_control *io_pads_control;
+	unsigned int num_io_pads;
 	bool has_tsense_reset;
 	bool has_gpu_clamps;
 };
@@ -196,6 +207,14 @@ static void tegra_pmc_writel(u32 value, unsigned long offset)
 	writel(value, pmc->base + offset);
 }
 
+static void tegra_pmc_read_modify_write(unsigned long offset, u32 mask, u32 val)
+{
+	u32 pmc_reg = tegra_pmc_readl(offset);
+
+	pmc_reg = (pmc_reg & ~mask) | (val & mask);
+	tegra_pmc_writel(pmc_reg, offset);
+}
+
 static inline bool tegra_powergate_state(int id)
 {
 	if (id == TEGRA_POWERGATE_3D && pmc->soc->has_gpu_clamps)
@@ -970,6 +989,165 @@ error:
 }
 EXPORT_SYMBOL(tegra_io_rail_power_off);
 
+#define TEGRA_IO_PADS_CONTROL(_pad, _dpd, _pwr)		\
+{							\
+	.pad_id = (TEGRA_IO_PAD_##_pad),		\
+	.dpd_bit_pos = (_dpd),				\
+	.pwr_val_pos = (_pwr),				\
+}
+
+struct tegra_io_pads_control tegra210_io_pads_control[] = {
+	TEGRA_IO_PADS_CONTROL(CSIA, 0, -1),
+	TEGRA_IO_PADS_CONTROL(CSIB, 1, -1),
+	TEGRA_IO_PADS_CONTROL(DSI, 2, -1),
+	TEGRA_IO_PADS_CONTROL(MIPI_BIAS, 3, -1),
+	TEGRA_IO_PADS_CONTROL(PEX_BIAS, 4, -1),
+	TEGRA_IO_PADS_CONTROL(PEX_CLK1, 5, -1),
+	TEGRA_IO_PADS_CONTROL(PEX_CLK2, 6, -1),
+	TEGRA_IO_PADS_CONTROL(USB0, 9, -1),
+	TEGRA_IO_PADS_CONTROL(USB1, 10, -1),
+	TEGRA_IO_PADS_CONTROL(USB2, 11, -1),
+	TEGRA_IO_PADS_CONTROL(USB_BIAS, 12, -1),
+	TEGRA_IO_PADS_CONTROL(UART, 14, -1),
+	TEGRA_IO_PADS_CONTROL(AUDIO, 17, -1),
+	TEGRA_IO_PADS_CONTROL(USB3, 18, -1),
+	TEGRA_IO_PADS_CONTROL(HSIC, 19, -1),
+	TEGRA_IO_PADS_CONTROL(DBG, 25, -1),
+	TEGRA_IO_PADS_CONTROL(DEBUG_NONAO, 26, -1),
+	TEGRA_IO_PADS_CONTROL(GPIO, 27, 21),
+	TEGRA_IO_PADS_CONTROL(HDMI, 28, -1),
+	TEGRA_IO_PADS_CONTROL(SDMMC1, 33, 12),
+	TEGRA_IO_PADS_CONTROL(SDMMC3, 34, 13),
+	TEGRA_IO_PADS_CONTROL(EMMC, 35, -1),
+	TEGRA_IO_PADS_CONTROL(CAM, 36, -1),
+	TEGRA_IO_PADS_CONTROL(EMMC2, 37, -1),
+	TEGRA_IO_PADS_CONTROL(DSIB, 39, -1),
+	TEGRA_IO_PADS_CONTROL(DSIC, 40, -1),
+	TEGRA_IO_PADS_CONTROL(DSID, 41, -1),
+	TEGRA_IO_PADS_CONTROL(CSIC, 42, -1),
+	TEGRA_IO_PADS_CONTROL(CSID, 43, -1),
+	TEGRA_IO_PADS_CONTROL(CSIE, 44, -1),
+	TEGRA_IO_PADS_CONTROL(CSIF, 45, -1),
+	TEGRA_IO_PADS_CONTROL(SPI, 46, -1),
+	TEGRA_IO_PADS_CONTROL(SPI_HV, 47, 23),
+	TEGRA_IO_PADS_CONTROL(DMIC, 50, -1),
+	TEGRA_IO_PADS_CONTROL(DP, 51, -1),
+	TEGRA_IO_PADS_CONTROL(LVDS, 57, -1),
+	TEGRA_IO_PADS_CONTROL(AUDIO_HV, 61, 18),
+};
+
+static int tegra_io_pads_to_dpd(const struct tegra_pmc_soc *soc, int pad_id)
+{
+	int i;
+
+	if (!soc || !soc->num_io_pads)
+		return -EINVAL;
+
+	for (i = 0; i < soc->num_io_pads; ++i) {
+		if (soc->io_pads_control[i].pad_id == pad_id)
+			return soc->io_pads_control[i].dpd_bit_pos;
+	}
+
+	return -EINVAL;
+}
+
+static int tegra_io_pads_to_power_val(const struct tegra_pmc_soc *soc,
+				      int pad_id)
+{
+	int i;
+
+	if (!soc || !soc->num_io_pads)
+		return -EINVAL;
+
+	for (i = 0; i < soc->num_io_pads; ++i) {
+		if (soc->io_pads_control[i].pad_id == pad_id)
+			return soc->io_pads_control[i].pwr_val_pos;
+	}
+
+	return -EINVAL;
+}
+
+int tegra_io_pads_power_enable(int io_pad_id)
+{
+	int dpd_bit;
+
+	dpd_bit = tegra_io_pads_to_dpd(pmc->soc, io_pad_id);
+	if (dpd_bit < 0)
+		return dpd_bit;
+
+	return tegra_io_rail_power_on(dpd_bit);
+}
+EXPORT_SYMBOL(tegra_io_pads_power_enable);
+
+int tegra_io_pads_power_disable(int io_pad_id)
+{
+	int dpd_bit;
+
+	dpd_bit = tegra_io_pads_to_dpd(pmc->soc, io_pad_id);
+	if (dpd_bit < 0)
+		return dpd_bit;
+
+	return tegra_io_rail_power_off(dpd_bit);
+}
+EXPORT_SYMBOL(tegra_io_pads_power_disable);
+
+int tegra_io_pads_power_is_enabled(int io_pad_id)
+{
+	unsigned long status_reg;
+	u32 status;
+	int dpd_bit;
+
+	dpd_bit = tegra_io_pads_to_dpd(pmc->soc, io_pad_id);
+	if (dpd_bit < 0)
+		return dpd_bit;
+
+	status_reg = (dpd_bit < 32) ? IO_DPD_STATUS : IO_DPD2_STATUS;
+	status = tegra_pmc_readl(status_reg);
+
+	return !!(status & BIT(dpd_bit % 32));
+}
+EXPORT_SYMBOL(tegra_io_pads_power_is_enabled);
+
+int tegra_io_pads_configure_voltage(int io_pad_id, int io_volt_uv)
+{
+	int pwr_bit;
+	u32 bval;
+
+	if ((io_volt_uv != 3300000) && (io_volt_uv != 1800000))
+		return -EINVAL;
+
+	pwr_bit = tegra_io_pads_to_power_val(pmc->soc, io_pad_id);
+	if (pwr_bit < 0)
+		return pwr_bit;
+
+	bval = (io_volt_uv == 3300000) ? BIT(pwr_bit) : 0;
+
+	mutex_lock(&pmc->powergates_lock);
+	tegra_pmc_read_modify_write(PMC_PWR_DET, BIT(pwr_bit), BIT(pwr_bit));
+	tegra_pmc_read_modify_write(PMC_PWR_DET_VAL, BIT(pwr_bit), bval);
+	mutex_unlock(&pmc->powergates_lock);
+
+	usleep_range(100, 250);
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_io_pads_configure_voltage);
+
+int tegra_io_pads_get_configured_voltage(int io_pad_id)
+{
+	int pwr_bit;
+	u32 pwr_det_val;
+
+	pwr_bit = tegra_io_pads_to_power_val(pmc->soc, io_pad_id);
+	if (pwr_bit < 0)
+		return pwr_bit;
+
+	pwr_det_val = tegra_pmc_readl(PMC_PWR_DET_VAL);
+
+	return (pwr_det_val & BIT(pwr_bit)) ? 3300000 : 1800000;
+}
+EXPORT_SYMBOL(tegra_io_pads_get_configured_voltage);
+
 #ifdef CONFIG_PM_SLEEP
 enum tegra_suspend_mode tegra_pmc_get_suspend_mode(void)
 {
@@ -1443,6 +1621,8 @@ static const struct tegra_pmc_soc tegra210_pmc_soc = {
 	.powergates = tegra210_powergates,
 	.num_cpu_powergates = ARRAY_SIZE(tegra210_cpu_powergates),
 	.cpu_powergates = tegra210_cpu_powergates,
+	.io_pads_control = tegra210_io_pads_control,
+	.num_io_pads = ARRAY_SIZE(tegra210_io_pads_control),
 	.has_tsense_reset = true,
 	.has_gpu_clamps = true,
 };
diff --git a/include/soc/tegra/pmc.h b/include/soc/tegra/pmc.h
index e9e5347..79e38f5 100644
--- a/include/soc/tegra/pmc.h
+++ b/include/soc/tegra/pmc.h
@@ -108,6 +108,58 @@ int tegra_pmc_cpu_remove_clamping(unsigned int cpuid);
 #define TEGRA_IO_RAIL_LVDS	57
 #define TEGRA_IO_RAIL_SYS_DDC	58
 
+/* TEGRA_IO_PAD: The IO pins of Tegra SoCs are grouped for common control
+ * of IO interface like setting voltage signal levels, power state of the
+ * interface. The group is generally referred as io-pads. The power and
+ * voltage control of IO pins are available at io-pads level.
+ * The following macros make the super list all IO pads found on Tegra SoC
+ * generations.
+ */
+#define TEGRA_IO_PAD_AUDIO		0
+#define TEGRA_IO_PAD_AUDIO_HV		1
+#define TEGRA_IO_PAD_BB			2
+#define TEGRA_IO_PAD_CAM		3
+#define TEGRA_IO_PAD_COMP		4
+#define TEGRA_IO_PAD_CSIA		5
+#define TEGRA_IO_PAD_CSIB		6
+#define TEGRA_IO_PAD_CSIC		7
+#define TEGRA_IO_PAD_CSID		8
+#define TEGRA_IO_PAD_CSIE		9
+#define TEGRA_IO_PAD_CSIF		10
+#define TEGRA_IO_PAD_DBG		11
+#define TEGRA_IO_PAD_DEBUG_NONAO	12
+#define TEGRA_IO_PAD_DMIC		13
+#define TEGRA_IO_PAD_DP			14
+#define TEGRA_IO_PAD_DSI		15
+#define TEGRA_IO_PAD_DSIB		16
+#define TEGRA_IO_PAD_DSIC		17
+#define TEGRA_IO_PAD_DSID		18
+#define TEGRA_IO_PAD_EMMC		19
+#define TEGRA_IO_PAD_EMMC2		20
+#define TEGRA_IO_PAD_GPIO		21
+#define TEGRA_IO_PAD_HDMI		22
+#define TEGRA_IO_PAD_HSIC		23
+#define TEGRA_IO_PAD_HV			24
+#define TEGRA_IO_PAD_LVDS		25
+#define TEGRA_IO_PAD_MIPI_BIAS		26
+#define TEGRA_IO_PAD_NAND		27
+#define TEGRA_IO_PAD_PEX_BIAS		28
+#define TEGRA_IO_PAD_PEX_CLK1		29
+#define TEGRA_IO_PAD_PEX_CLK2		30
+#define TEGRA_IO_PAD_PEX_CNTRL		31
+#define TEGRA_IO_PAD_SDMMC1		32
+#define TEGRA_IO_PAD_SDMMC3		33
+#define TEGRA_IO_PAD_SDMMC4		34
+#define TEGRA_IO_PAD_SPI		35
+#define TEGRA_IO_PAD_SPI_HV		36
+#define TEGRA_IO_PAD_SYS_DDC		37
+#define TEGRA_IO_PAD_UART		38
+#define TEGRA_IO_PAD_USB0		39
+#define TEGRA_IO_PAD_USB1		40
+#define TEGRA_IO_PAD_USB2		41
+#define TEGRA_IO_PAD_USB3		42
+#define TEGRA_IO_PAD_USB_BIAS		43
+
 #ifdef CONFIG_ARCH_TEGRA
 int tegra_powergate_is_powered(unsigned int id);
 int tegra_powergate_power_on(unsigned int id);
@@ -120,6 +172,16 @@ int tegra_powergate_sequence_power_up(unsigned int id, struct clk *clk,
 
 int tegra_io_rail_power_on(unsigned int id);
 int tegra_io_rail_power_off(unsigned int id);
+
+/* Power enable/disable of the IO pads */
+int tegra_io_pads_power_enable(int io_pad_id);
+int tegra_io_pads_power_disable(int io_pad_id);
+int tegra_io_pads_power_is_enabled(int io_pad_id);
+
+/* Set/Get of IO pad voltage */
+int tegra_io_pads_configure_voltage(int io_pad_id, int io_volt_uv);
+int tegra_io_pads_get_configured_voltage(int io_pad_id);
+
 #else
 static inline int tegra_powergate_is_powered(unsigned int id)
 {
@@ -157,6 +219,31 @@ static inline int tegra_io_rail_power_off(unsigned int id)
 {
 	return -ENOSYS;
 }
+
+static inline int tegra_io_pads_power_enable(int io_pad_id)
+{
+	return -ENOTSUPP;
+}
+
+static inline int tegra_io_pads_power_disable(int io_pad_id)
+{
+	return -ENOTSUPP;
+}
+
+static inline int tegra_io_pads_power_is_enabled(int io_pad_id)
+{
+	return -ENOTSUPP;
+}
+
+static inline int tegra_io_pads_configure_voltage(int io_pad_id, int io_volt_uv)
+{
+	return -ENOTSUPP;
+}
+
+static inline int tegra_io_pads_get_configured_voltage(int io_pad_id)
+{
+	return -ENOTSUPP;
+}
 #endif /* CONFIG_ARCH_TEGRA */
 
 #endif /* __SOC_TEGRA_PMC_H__ */
-- 
2.1.4

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