OMAP2+: UART: Add mechanism to probe uart pins and configure rx wakeup

From: "Govindraj.R" <[email protected]>

The commit (bce492c0 ARM: OMAP2+: UART: Fix incorrect population of default uart pads) removed default uart pads that where getting populated and which was making rx pin wakeup capable. If uart pads was used in

Quoted 5 lines · Govindraj.R

From: "Govindraj.R" <[email protected]>

The commit (bce492c0 ?ARM: OMAP2+: UART: Fix incorrect population of default uart pads) removed default uart pads that where getting populated and which was making rx pin wakeup capable. If uart pads was used in

Nitpick.. this should say "were used" here ? ? ? ? ? ? ? ? ^^^

arch/arm/mach-omap2/serial.c void __init omap_serial_board_init(struct omap_uart_port_info *info) · line 356

Quoted 10 lines

arch/arm/mach-omap2/serial.c +1 -2

@@ -295,8 +353,7 @@ void __init omap_serial_board_init(struct omap_uart_port_info *info)
 ? ? ? ? ? ? ? bdata.pads = NULL;
 ? ? ? ? ? ? ? bdata.pads_cnt = 0;
 
- ? ? ? ? ? ? if (cpu_is_omap44xx() || cpu_is_omap34xx())
- ? ? ? ? ? ? ? ? ? ? omap_serial_fill_default_pads(&bdata);
+ ? ? ? ? ? ? omap_serial_check_wakeup(&bdata, uart);

Should this section become:

? ? ? ? ? ? ? ?if (!info) {
? ? ? ? ? ? ? ? ? ? ? ?omap_serial_check_wakeup(&bdata, uart); ? ? ? ? ? ? ? ? ? ? ? ?omap_serial_init_port(&bdata, NULL); ? ? ? ? ? ? ? ?} else {
? ? ? ? ? ? ? ? ? ? ? ?omap_serial_init_port(&bdata, &info[uart->num]); ? ? ? ? ? ? ? ?}

As if you have bdata, then there should not be anything to mux, right?

From: "Govindraj.R" <[email protected]>

The commit (bce492c0 ?ARM: OMAP2+: UART: Fix incorrect population of default uart pads) removed default uart pads that where getting populated and which was making rx pin wakeup capable. If uart pads was used in different mode by any other module then it would fail since the default pads took over all the uart pins forcefully. With removal of default pads the rx_pad wakeup for console uart while waking up from off mode is broken.

Utilise the mux api available to probe the availability of mux pins in uart mode and probe for availability of uart pin in mux mode0 if uart is available as uart pin itself then configure rx pin as wakeup capable.

This patch itself doesn't cater to all boards. Boards using uart rx wakeup mechanism should ensure the usage of omap_serial_init_port by configuring required uart ports and pass necessary mux data, till then this probing of uart pins can cater to enabling of rx pad wakeup to most of the boards.

This patch can also throw some boot warning from _omap_mux_get_by_name if pin is requested for availability is not present while dynamically probing the uart pins availability such boot warnings can be addressed only when board files are patched with omap_serial_init_port calls passing the right pads needed for a given port.

Discussion Threads for reference:
http://www.spinics.net/lists/linux-omap/msg69859.html
http://www.spinics.net/lists/linux-omap/msg68659.html

Cc Felipe Balbi <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Russ Dill <[email protected]>

Cc Tony Lindgren <[email protected]>

Cc Paul Walmsley <[email protected]>

Cc Ameya Palande <[email protected]>

Signed-off-by Govindraj.R <[email protected]>

---

Patching of all board files would be difficult as even I am not aware of all omap-board schematics and uart port usage. So individual board file can be enabled accordingly for uart usage by calling omap_serial_init_port call with right mux data.

for testing: Patch based on v3.4-rc6
(tested on beagle-xm for off mode rx wakeup)
Patch targeted for v3.5

?arch/arm/mach-omap2/mux.c ? ?| ? ?3 +-
?arch/arm/mach-omap2/mux.h ? ?| ? 10 ++++++
?arch/arm/mach-omap2/serial.c | ? 65 +++++++++++++++++++++++++++++++++++++++--

?3 files changed, 72 insertions(+), 6 deletions(-)

arch/arm/mach-omap2/mux.c +1 -2

index 65c3391..d937ddd 100644
@@ -217,8 +217,7 @@ static int __init _omap_mux_get_by_name(struct omap_mux_partition *partition,
 ? ? ? ?return -ENODEV;
 ?}
 
-static int __init
-omap_mux_get_by_name(const char *muxname,
+int __init omap_mux_get_by_name(const char *muxname,
 ? ? ? ? ? ? ? ? ? ? ? ?struct omap_mux_partition **found_partition,
 ? ? ? ? ? ? ? ? ? ? ? ?struct omap_mux **found_mux)
 ?{

arch/arm/mach-omap2/mux.h +0 -0

index 69fe060..68927f1 100644
@@ -225,8 +225,18 @@ omap_hwmod_mux_init(struct omap_device_pad *bpads, int nr_pads);

?*/
?void omap_hwmod_mux(struct omap_hwmod_mux_info *hmux, u8 state);

+int omap_mux_get_by_name(const char *muxname,
+ ? ? ? ? ? ? ? struct omap_mux_partition **found_partition,
+ ? ? ? ? ? ? ? struct omap_mux **found_mux); ?#else

arch/arm/mach-omap2/mux.h +7 -0

+static inline int omap_mux_get_by_name(const char *muxname,
+ ? ? ? ? ? ? ? struct omap_mux_partition **found_partition,
+ ? ? ? ? ? ? ? struct omap_mux **found_mux)
+{
+ ? ? ? return 0;
+}
+

?static inline int omap_mux_init_gpio(int gpio, int val) ?{
? ? ? ?return 0;

arch/arm/mach-omap2/serial.c +1 -0

index 9fc2f44..c097317 100644
@@ -57,6 +57,7 @@ struct omap_uart_state {
 
 ? ? ? ?struct list_head node;
 ? ? ? ?struct omap_hwmod *oh;
+ ? ? ? struct omap_device_pad default_omap_uart_pads[2];
 ?};
 
 ?static LIST_HEAD(uart_list);

@@ -126,11 +127,68 @@ static void omap_uart_set_smartidle(struct platform_device *pdev) {}

?#endif /* CONFIG_PM */

?#ifdef CONFIG_OMAP_MUX

arch/arm/mach-omap2/serial.c +24 -1

-static void omap_serial_fill_default_pads(struct omap_board_data *bdata)
+
+#define OMAP_UART_DEFAULT_PAD_NAME_LEN 28
+static char rx_pad_name[OMAP_UART_DEFAULT_PAD_NAME_LEN],
+ ? ? ? ? ? ? ? tx_pad_name[OMAP_UART_DEFAULT_PAD_NAME_LEN] __initdata;
+
+static void ?__init
+omap_serial_fill_uart_tx_rx_pads(struct omap_board_data *bdata,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct omap_uart_state *uart)
+{
+ ? ? ? uart->default_omap_uart_pads[0].name = rx_pad_name;
+ ? ? ? uart->default_omap_uart_pads[0].flags = OMAP_DEVICE_PAD_REMUX |
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? OMAP_DEVICE_PAD_WAKEUP;
+ ? ? ? uart->default_omap_uart_pads[0].enable = OMAP_PIN_INPUT |
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? OMAP_MUX_MODE0;
+ ? ? ? uart->default_omap_uart_pads[0].idle = OMAP_PIN_INPUT | OMAP_MUX_MODE0;
+ ? ? ? uart->default_omap_uart_pads[1].name = tx_pad_name;
+ ? ? ? uart->default_omap_uart_pads[1].enable = OMAP_PIN_OUTPUT |
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? OMAP_MUX_MODE0;
+ ? ? ? bdata->pads = uart->default_omap_uart_pads;
+ ? ? ? bdata->pads_cnt = ARRAY_SIZE(uart->default_omap_uart_pads);
+}
+
+static void ?__init omap_serial_check_wakeup(struct omap_board_data *bdata,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct omap_uart_state *uart)

?{
+ ? ? ? struct omap_mux_partition *tx_partition = NULL, *rx_partition = NULL;
+ ? ? ? struct omap_mux *rx_mux = NULL, *tx_mux = NULL;
+ ? ? ? char *rx_fmt, *tx_fmt;
+ ? ? ? int uart_nr = bdata->id + 1;

arch/arm/mach-omap2/serial.c +18 -0

+
+ ? ? ? if (bdata->id != 2) {
+ ? ? ? ? ? ? ? rx_fmt = "uart%d_rx.uart%d_rx";
+ ? ? ? ? ? ? ? tx_fmt = "uart%d_tx.uart%d_tx";
+ ? ? ? } else {
+ ? ? ? ? ? ? ? rx_fmt = "uart%d_rx_irrx.uart%d_rx_irrx";
+ ? ? ? ? ? ? ? tx_fmt = "uart%d_tx_irtx.uart%d_tx_irtx";
+ ? ? ? }
+
+ ? ? ? snprintf(rx_pad_name, OMAP_UART_DEFAULT_PAD_NAME_LEN, rx_fmt,
+ ? ? ? ? ? ? ? ? ? ? ? uart_nr, uart_nr);
+ ? ? ? snprintf(tx_pad_name, OMAP_UART_DEFAULT_PAD_NAME_LEN, tx_fmt,
+ ? ? ? ? ? ? ? ? ? ? ? uart_nr, uart_nr);
+
+ ? ? ? if (omap_mux_get_by_name(rx_pad_name, &rx_partition, &rx_mux) >= 0 &&
+ ? ? ? ? ? ? ? ? ? ? ? omap_mux_get_by_name
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (tx_pad_name, &tx_partition, &tx_mux) >= 0) {
+ ? ? ? ? ? ? ? u16 tx_mode, rx_mode;

+ ? ? ? }
?}
?#else

arch/arm/mach-omap2/serial.c +2 -1

-static void omap_serial_fill_default_pads(struct omap_board_data *bdata) {}
+static void __init omap_serial_check_wakeup(struct omap_board_data *bdata
+ ? ? ? ? ? ? ? struct omap_uart_state *uart) {}

?#endif

?char *cmdline_find_option(char *str)

arch/arm/mach-omap2/serial.c +1 -3

@@ -295,8 +353,7 @@ void __init omap_serial_board_init(struct omap_uart_port_info *info)
 ? ? ? ? ? ? ? ?bdata.pads = NULL;
 ? ? ? ? ? ? ? ?bdata.pads_cnt = 0;
 
- ? ? ? ? ? ? ? if (cpu_is_omap44xx() || cpu_is_omap34xx())
- ? ? ? ? ? ? ? ? ? ? ? omap_serial_fill_default_pads(&bdata);
+ ? ? ? ? ? ? ? omap_serial_check_wakeup(&bdata, uart);
 
 ? ? ? ? ? ? ? ?if (!info)
 ? ? ? ? ? ? ? ? ? ? ? ?omap_serial_init_port(&bdata, NULL);
--

1.7.9

Quoted 8 lines · Govindraj.R

From: "Govindraj.R" <[email protected]>

The commit (bce492c0 ?ARM: OMAP2+: UART: Fix incorrect population of default uart pads) removed default uart pads that where getting populated and which was making rx pin wakeup capable. If uart pads was used in different mode by any other module then it would fail since the default pads took over all the uart pins forcefully. With removal of default pads the rx_pad wakeup for console uart while waking up from off mode is broken.

Quoted 5 lines

+ ? ? ? ? ? ? ? ?* Check if uart is used in default tx/rx mode i.e. in mux mode0
+ ? ? ? ? ? ? ? ?* if yes then configure rx pin for wake up capability
+ ? ? ? ? ? ? ? ?*/
+ ? ? ? ? ? ? ? if (!(rx_mode & 0x07) && !(tx_mode & 0x07))
+ ? ? ? ? ? ? ? ? ? ? ? omap_serial_fill_uart_tx_rx_pads(bdata, uart);

I realize the comment makes it clear, but it'd probably be better to just make the code clear. I noticed mux.h has a OMAP_MODE_GPIO(x) macro for testing if a mux is in mode4. Perhaps its time to start expanding on that, at least with a macro like:

#define OMAP_MUX_MODE(x) ((x) & OMAP_MUX_MODE7)

So you can do a OMAP_MUX_MODE(rx_mode) == OMAP_MUX_MODE0

From: "Govindraj.R" <[email protected]>

The commit (bce492c0 ARM: OMAP2+: UART: Fix incorrect population of default uart pads) removed default uart pads that where getting populated and which was making rx pin wakeup capable. If uart pads were used in different mode by any other module then it would fail since the default pads took over all the uart pins forcefully. With removal of default pads the rx_pad wakeup for console uart while waking up from off mode is broken.

Utilise the mux api available to probe the availability of mux pins in uart mode and probe for availability of uart pin in mux mode0 if uart is available as uart pin itself then configure rx pin as wakeup capable.

This patch itself doesn't cater to all boards. Boards using uart rx wakeup mechanism should ensure the usage of omap_serial_init_port by configuring required uart ports and pass necessary mux data, till then this probing of uart pins can cater to enabling of rx pad wakeup to most of the boards.

This patch can also throw some boot warning from _omap_mux_get_by_name if pin is requested for availability is not present while dynamically probing the uart pins availability such boot warnings can be addressed only when board files are patched with omap_serial_init_port calls passing the right pads needed for a given port.

Discussion Threads for reference:
http://www.spinics.net/lists/linux-omap/msg69859.html
http://www.spinics.net/lists/linux-omap/msg68659.html

Cc Felipe Balbi <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Russ Dill <[email protected]>

Cc Tony Lindgren <[email protected]>

Cc Paul Walmsley <[email protected]>

Cc Ameya Palande <[email protected]>

Signed-off-by Govindraj.R <[email protected]>

Quoted 29 lines · Govindraj.R

From: "Govindraj.R" <[email protected]>

The commit (bce492c0 ARM: OMAP2+: UART: Fix incorrect population of default uart pads) removed default uart pads that where getting populated and which was making rx pin wakeup capable. If uart pads were used in different mode by any other module then it would fail since the default pads took over all the uart pins forcefully. With removal of default pads the rx_pad wakeup for console uart while waking up from off mode is broken.

Utilise the mux api available to probe the availability of mux pins in uart mode and probe for availability of uart pin in mux mode0 if uart is available as uart pin itself then configure rx pin as wakeup capable.

This patch itself doesn't cater to all boards. Boards using uart rx wakeup mechanism should ensure the usage of omap_serial_init_port by configuring required uart ports and pass necessary mux data, till then this probing of uart pins can cater to enabling of rx pad wakeup to most of the boards.

This patch can also throw some boot warning from _omap_mux_get_by_name if pin is requested for availability is not present while dynamically probing the uart pins availability such boot warnings can be addressed only when board files are patched with omap_serial_init_port calls passing the right pads needed for a given port.

Discussion Threads for reference:
http://www.spinics.net/lists/linux-omap/msg69859.html
http://www.spinics.net/lists/linux-omap/msg68659.html

Quoted 7 lines

Cc Felipe Balbi <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Russ Dill <[email protected]>

Cc Tony Lindgren <[email protected]>

Cc Paul Walmsley <[email protected]>

Cc Ameya Palande <[email protected]>

Signed-off-by Govindraj.R <[email protected]>

Tony, it's up to you if you're OK with this mux interface, but I can at least confirm that this gets runtime PM + UART wakeups working again on the boards I tried: 3530/Overo, 3430/n900, 3530/OMAP3EVM.