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imx: Easy enabling of SION per-pin using MUX_MODE_SION helper macro

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The macro allows easy setting in per-pin, as for example:

,----
| imx_iomux_v3_setup_pad(MX6_PAD_NANDF_D1__GPIO_2_1 | MUX_MODE_SION);
`----

The IOMUX_CONFIG_SION allows for reading PAD value from PSR register.

The following quote from the datasheet:

,----
| ...
| 28.4.2.2 GPIO Write Mode
| The programming sequence for driving output signals should be as follows:
| 1. Configure IOMUX to select GPIO mode (Via IOMUXC), also enable SION if need
| to read loopback pad value through PSR
| 2. Configure GPIO direction register to output (GPIO_GDIR[GDIR] set to 1b).
| 3. Write value to data register (GPIO_DR).
| ...
`----

This fixes the gpio_get_value to properly work when a GPIO is set for
output and has no conflicts.

Thanks for Benoît Thébaudeau <benoit.thebaudeau@advansee.com>, Fabio
Estevam <fabio.estevam@freescale.com> and Eric Bénard
<eric@eukrea.com> for helping to properly trace this down.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Stefano Babic <sbabic@denx.de>
This commit is contained in:
Otavio Salvador 2013-12-16 20:44:00 -02:00 committed by Stefano Babic
parent 0222982780
commit 7773fd1969
1 changed files with 2 additions and 0 deletions
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2
arch/arm/include/asm/imx-common/iomux-v3.h
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@ -63,6 +63,8 @@ typedef u64 iomux_v3_cfg_t;
#define MUX_SEL_INPUT_SHIFT 59
#define MUX_SEL_INPUT_MASK ((iomux_v3_cfg_t)0xf << MUX_SEL_INPUT_SHIFT)
#define MUX_MODE_SION ((iomux_v3_cfg_t)IOMUX_CONFIG_SION << \
MUX_MODE_SHIFT)
#define MUX_PAD_CTRL(x) ((iomux_v3_cfg_t)(x) << MUX_PAD_CTRL_SHIFT)
#define IOMUX_PAD(pad_ctrl_ofs, mux_ctrl_ofs, mux_mode, sel_input_ofs, \