Re: [PATCH 2/2] pinctrl: bcm: add Northstar driver

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On 9/19/18 11:45 PM, Florian Fainelli wrote:
On 09/19/2018 02:02 PM, Rafał Miłecki wrote:
From: Rafał Miłecki <rafal@xxxxxxxxxx>

This driver provides support for Northstar mux controller. It differs
from Northstar Plus one so a new binding and driver were needed.

Right now it includes support for SPI pins only which is caused by a
lack of access to Broadcom's datasheet. SPI pins info was extracted from
the Broadcom's SDK. Once more pins are discovered they can be added to
the driver without breaking any existing setups.

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---

[snip]

+static const struct pinctrl_pin_desc ns_pinctrl_pins[] = {
+	{ 0, "spi_clk" },
+	{ 1, "spi_ss" },
+	{ 2, "spi_mosi" },
+	{ 3, "spi_miso" },
+};

In case you are interested, here are the additional functions:

4: i2c_scl
5: i2c_sda

6: mdc
7: mdio

8: pwm0
9: pwm1
10: pwm2
11: pwm3

12: uart1_rx
13: uart1_tx
14: uart1_cts
15: uart1_rts

On BCM53012:

16: uart2_rx
17: uart2_tx
22: sdio_card_power_ctl
23: sdio_en_1p8

On BCM53013:

21: 25Mhz crystal output for I2S

I believe what you provided are name of bits in the cru_genpll_control0
register. FWIW that info would be part of ns_pins_data rather than
ns_pinctrl_pins.

I was aware of most of them thanks to analyzing bcm5301x_dmu.c from the
SDK but some are still new to me, so thanks for that!

What I'm really missing are SoC pin numbers for all above. E.g. what
hardware pin number is used for the uart2_rx? Or sdio_card_power_ctl?
And all the other ones.

If you could provide that info it'd be extremely helpful.

***

If you take a look at pinctrl-nsp-mux.c, you'll see that there isn't 1:1
mapping used on Broadcom platforms.

E.g. Northstar Plus has SoC pins 4 and 5 used for I2C:
i2c_pins[] = {4, 5};
but they are controlled by BIT(3) and BIT(4) of the BASE0 register:
NSP_PIN_GROUP(i2c, NSP_MUX_BASE0, 3, 0x03, 0x00),
(0x03 << 3)

Another NSP example: SoC pins 16 and 17 are used for UART2:
uart2_pins[] = {16, 17};
but they are controlled by BIT(15) and BIT(16) of the BASE0 register:
NSP_PIN_GROUP(uart2, NSP_MUX_BASE0, 15, 0x03, 0x00),
(0x03 << 15)

Of course, some pins map 1:1, e.g. pin 26 for LED of switch port 5:
switch_p05_led0_pins[] = {26};
maps nicely to BIT(26) of the BASE0 register:
NSP_PIN_GROUP(switch_p05_led0, NSP_MUX_BASE0, 26, 0x01, 0x01),
(0x01 << 26)
but it clearly isn't a rule.



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