[v2,4/4] ARM: dts: meson: consistently disable pin bias
diff mbox series

Message ID 20181109140445.17795-5-jbrunet@baylibre.com
State New
Headers show
Series
  • ARM: dts: meson: set pinmux bias
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Commit Message

Jerome Brunet Nov. 9, 2018, 2:04 p.m. UTC
On Amlogic chipsets, the bias set through pinconf applies to the pad
itself, not only the GPIO function. This means that even when we change
the function of the pad from GPIO to anything else, the bias previously
set still applies.

As we have seen with the eMMC, depending on the bias type and the function,
it may trigger problems.

The underlying issue is that we inherit whatever was left by previous user
of the pad (pinconf, u-boot or the ROM code). As a consequence, the actual
setup we will get is undefined.

There is nothing mentioned in the documentation about pad bias and pinmux
function, however leaving it undefined is not an option.

This change consistently disable the pad bias for every pinmux functions.
It seems to work well, we can only assume that the necessary bias (if any)
is already provided by the pin function itself.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 arch/arm/boot/dts/meson8.dtsi   | 12 ++++++++++++
 arch/arm/boot/dts/meson8b.dtsi  |  9 +++++++++
 arch/arm/boot/dts/meson8m2.dtsi |  1 +
 3 files changed, 22 insertions(+)

Comments

Martin Blumenstingl Nov. 16, 2018, 6:45 a.m. UTC | #1
On Fri, Nov 9, 2018 at 3:05 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
>
> On Amlogic chipsets, the bias set through pinconf applies to the pad
> itself, not only the GPIO function. This means that even when we change
> the function of the pad from GPIO to anything else, the bias previously
> set still applies.
>
> As we have seen with the eMMC, depending on the bias type and the function,
> it may trigger problems.
>
> The underlying issue is that we inherit whatever was left by previous user
> of the pad (pinconf, u-boot or the ROM code). As a consequence, the actual
> setup we will get is undefined.
>
> There is nothing mentioned in the documentation about pad bias and pinmux
> function, however leaving it undefined is not an option.
>
> This change consistently disable the pad bias for every pinmux functions.
> It seems to work well, we can only assume that the necessary bias (if any)
> is already provided by the pin function itself.
>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>

my Odroid-C1 still boots fine from SD card and Ethernet (ping) also still works

Kevin, can you please move this patch from your v4.21/dt64 branch to
the v4.21/dt (32-bit) branch?
all other patches from this series are for the 64-bit SoCs, so only
this single patch has to be moved


Thank you!
Regards
Martin

Patch
diff mbox series

diff --git a/arch/arm/boot/dts/meson8.dtsi b/arch/arm/boot/dts/meson8.dtsi
index 7162e0ca05b0..08c54cf5420a 100644
--- a/arch/arm/boot/dts/meson8.dtsi
+++ b/arch/arm/boot/dts/meson8.dtsi
@@ -163,6 +163,7 @@ 
 			mux {
 				groups = "uart_tx_ao_a", "uart_rx_ao_a";
 				function = "uart_ao";
+				bias-disable;
 			};
 		};
 
@@ -170,6 +171,7 @@ 
 			mux {
 				groups = "i2c_mst_sck_ao", "i2c_mst_sda_ao";
 				function = "i2c_mst_ao";
+				bias-disable;
 			};
 		};
 
@@ -177,6 +179,7 @@ 
 			mux {
 				groups = "remote_input";
 				function = "remote";
+				bias-disable;
 			};
 		};
 
@@ -184,6 +187,7 @@ 
 			mux {
 				groups = "pwm_f_ao";
 				function = "pwm_f_ao";
+				bias-disable;
 			};
 		};
 	};
@@ -238,6 +242,7 @@ 
 				groups = "sd_d0_a", "sd_d1_a", "sd_d2_a",
 					"sd_d3_a", "sd_clk_a", "sd_cmd_a";
 				function = "sd_a";
+				bias-disable;
 			};
 		};
 
@@ -246,6 +251,7 @@ 
 				groups = "sd_d0_b", "sd_d1_b", "sd_d2_b",
 					"sd_d3_b", "sd_clk_b", "sd_cmd_b";
 				function = "sd_b";
+				bias-disable;
 			};
 		};
 
@@ -254,6 +260,7 @@ 
 				groups = "sd_d0_c", "sd_d1_c", "sd_d2_c",
 					"sd_d3_c", "sd_clk_c", "sd_cmd_c";
 				function = "sd_c";
+				bias-disable;
 			};
 		};
 
@@ -261,6 +268,7 @@ 
 			mux {
 				groups = "nor_d", "nor_q", "nor_c", "nor_cs";
 				function = "nor";
+				bias-disable;
 			};
 		};
 
@@ -272,6 +280,7 @@ 
 					 "eth_rxd1", "eth_rxd0", "eth_mdio",
 					 "eth_mdc";
 				function = "ethernet";
+				bias-disable;
 			};
 		};
 
@@ -279,6 +288,7 @@ 
 			mux {
 				groups = "pwm_e";
 				function = "pwm_e";
+				bias-disable;
 			};
 		};
 
@@ -287,6 +297,7 @@ 
 				groups = "uart_tx_a1",
 				       "uart_rx_a1";
 				function = "uart_a";
+				bias-disable;
 			};
 		};
 
@@ -295,6 +306,7 @@ 
 				groups = "uart_cts_a1",
 				       "uart_rts_a1";
 				function = "uart_a";
+				bias-disable;
 			};
 		};
 	};
diff --git a/arch/arm/boot/dts/meson8b.dtsi b/arch/arm/boot/dts/meson8b.dtsi
index cd1ca9dda126..46b3564a6536 100644
--- a/arch/arm/boot/dts/meson8b.dtsi
+++ b/arch/arm/boot/dts/meson8b.dtsi
@@ -146,6 +146,7 @@ 
 			mux {
 				groups = "uart_tx_ao_a", "uart_rx_ao_a";
 				function = "uart_ao";
+				bias-disable;
 			};
 		};
 
@@ -153,6 +154,7 @@ 
 			mux {
 				groups = "remote_input";
 				function = "remote";
+				bias-disable;
 			};
 		};
 	};
@@ -220,6 +222,7 @@ 
 					 "eth_txd2",
 					 "eth_txd3";
 				function = "ethernet";
+				bias-disable;
 			};
 		};
 
@@ -235,6 +238,7 @@ 
 					 "eth_mdio_en",
 					 "eth_mdc";
 				function = "ethernet";
+				bias-disable;
 			};
 		};
 
@@ -242,6 +246,7 @@ 
 			mux {
 				groups = "i2c_sda_a", "i2c_sck_a";
 				function = "i2c_a";
+				bias-disable;
 			};
 		};
 
@@ -250,6 +255,7 @@ 
 				groups = "sd_d0_b", "sd_d1_b", "sd_d2_b",
 					"sd_d3_b", "sd_clk_b", "sd_cmd_b";
 				function = "sd_b";
+				bias-disable;
 			};
 		};
 
@@ -257,6 +263,7 @@ 
 			mux {
 				groups = "pwm_c1";
 				function = "pwm_c";
+				bias-disable;
 			};
 		};
 
@@ -265,6 +272,7 @@ 
 				groups = "uart_tx_b0",
 				       "uart_rx_b0";
 				function = "uart_b";
+				bias-disable;
 			};
 		};
 
@@ -273,6 +281,7 @@ 
 				groups = "uart_cts_b0",
 				       "uart_rts_b0";
 				function = "uart_b";
+				bias-disable;
 			};
 		};
 	};
diff --git a/arch/arm/boot/dts/meson8m2.dtsi b/arch/arm/boot/dts/meson8m2.dtsi
index 3e1f92273d7b..d1a28c2adac5 100644
--- a/arch/arm/boot/dts/meson8m2.dtsi
+++ b/arch/arm/boot/dts/meson8m2.dtsi
@@ -45,6 +45,7 @@ 
 				 "eth_rxd1", "eth_rxd0",
 				 "eth_mdio", "eth_mdc";
 			function = "ethernet";
+			bias-disable;
 		};
 	};
 };