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Date: Tue, 17 May 2011 10:53:07 +0530
From: Shreshtha Kumar SAHU <shreshthakumar.sahu@...ricsson.com>
To: <linux-serial@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<rmk+kernel@....linux.org.uk>, <linus.walleij@...ricsson.com>,
<alan@...ux.intel.com>
Cc: <shreshthakumar.sahu@...ricsson.com>
Subject: [PATCHv2 2/2] amba pl011: platform data for reg lockup and glitch
From: Shreshtha Kumar Sahu <shreshthakumar.sahu@...ricsson.com>
This patch provides platform data for following
- uart reset function to assist uart register lockup workaround
- init/exit function to fix glitch in the tx pin in tty_open
when tty port0 is opened a glitch is seen in the tx line
of uart0. This happens in pl011_startup() when tx fifo
interrupt is provoked into asserting.
Now uart0 pins are enabled (alt function) only when init
is complete and turned back to gpio when closed.
Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@...ricsson.com>
---
changes in v2:
corrected function name in commit message
added missing header file include
arch/arm/mach-ux500/board-mop500-pins.c | 16 +++++++--
arch/arm/mach-ux500/board-mop500.c | 54 +++++++++++++++++++++++++++++++
2 files changed, 66 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-ux500/board-mop500-pins.c b/arch/arm/mach-ux500/board-mop500-pins.c
index fd4cf1c..ceab640 100644
--- a/arch/arm/mach-ux500/board-mop500-pins.c
+++ b/arch/arm/mach-ux500/board-mop500-pins.c
@@ -110,10 +110,18 @@ static pin_cfg_t mop500_pins_common[] = {
GPIO168_KP_O0,
/* UART */
- GPIO0_U0_CTSn | PIN_INPUT_PULLUP,
- GPIO1_U0_RTSn | PIN_OUTPUT_HIGH,
- GPIO2_U0_RXD | PIN_INPUT_PULLUP,
- GPIO3_U0_TXD | PIN_OUTPUT_HIGH,
+ /* uart-0 pins gpio configuration should be
+ * kept intact to prevent glitch in tx line
+ * when tty dev is opened. Later these pins
+ * are configured to uart mop500_pins_uart0
+ *
+ * It will be replaced with uart configuration
+ * once the issue is solved.
+ */
+ GPIO0_GPIO | PIN_INPUT_PULLUP,
+ GPIO1_GPIO | PIN_OUTPUT_HIGH,
+ GPIO2_GPIO | PIN_INPUT_PULLUP,
+ GPIO3_GPIO | PIN_OUTPUT_LOW,
GPIO29_U2_RXD | PIN_INPUT_PULLUP,
GPIO30_U2_TXD | PIN_OUTPUT_HIGH,
diff --git a/arch/arm/mach-ux500/board-mop500.c b/arch/arm/mach-ux500/board-mop500.c
index 6e1907fa..97b2577 100644
--- a/arch/arm/mach-ux500/board-mop500.c
+++ b/arch/arm/mach-ux500/board-mop500.c
@@ -27,18 +27,21 @@
#include <linux/leds-lp5521.h>
#include <linux/input.h>
#include <linux/gpio_keys.h>
+#include <linux/delay.h>
#include <asm/mach-types.h>
#include <asm/mach/arch.h>
#include <plat/i2c.h>
#include <plat/ste_dma40.h>
+#include <plat/pincfg.h>
#include <mach/hardware.h>
#include <mach/setup.h>
#include <mach/devices.h>
#include <mach/irqs.h>
+#include "pins-db8500.h"
#include "ste-dma40-db8500.h"
#include "devices-db8500.h"
#include "board-mop500.h"
@@ -391,12 +394,63 @@ static struct stedma40_chan_cfg uart2_dma_cfg_tx = {
};
#endif
+
+static pin_cfg_t mop500_pins_uart0[] = {
+ GPIO0_U0_CTSn | PIN_INPUT_PULLUP,
+ GPIO1_U0_RTSn | PIN_OUTPUT_HIGH,
+ GPIO2_U0_RXD | PIN_INPUT_PULLUP,
+ GPIO3_U0_TXD | PIN_OUTPUT_HIGH,
+};
+
+#define PRCC_K_SOFTRST_SET 0x18
+#define PRCC_K_SOFTRST_CLEAR 0x1C
+static void ux500_uart0_reset(void)
+{
+ void __iomem *prcc_rst_set, *prcc_rst_clr;
+
+ prcc_rst_set = (void __iomem *)IO_ADDRESS(U8500_CLKRST1_BASE +
+ PRCC_K_SOFTRST_SET);
+ prcc_rst_clr = (void __iomem *)IO_ADDRESS(U8500_CLKRST1_BASE +
+ PRCC_K_SOFTRST_CLEAR);
+
+ /* Activate soft reset PRCC_K_SOFTRST_CLEAR */
+ writel((readl(prcc_rst_clr) | 0x1), prcc_rst_clr);
+ udelay(1);
+
+ /* Release soft reset PRCC_K_SOFTRST_SET */
+ writel((readl(prcc_rst_set) | 0x1), prcc_rst_set);
+ udelay(1);
+}
+
+static void ux500_uart0_init(void)
+{
+ int ret;
+
+ ret = nmk_config_pins(mop500_pins_uart0,
+ ARRAY_SIZE(mop500_pins_uart0));
+ if (ret < 0)
+ pr_err("pl011: uart pins_enable failed\n");
+}
+
+static void ux500_uart0_exit(void)
+{
+ int ret;
+
+ ret = nmk_config_pins_sleep(mop500_pins_uart0,
+ ARRAY_SIZE(mop500_pins_uart0));
+ if (ret < 0)
+ pr_err("pl011: uart pins_disable failed\n");
+}
+
static struct amba_pl011_data uart0_plat = {
#ifdef CONFIG_STE_DMA40
.dma_filter = stedma40_filter,
.dma_rx_param = &uart0_dma_cfg_rx,
.dma_tx_param = &uart0_dma_cfg_tx,
#endif
+ .init = ux500_uart0_init,
+ .exit = ux500_uart0_exit,
+ .reset = ux500_uart0_reset,
};
static struct amba_pl011_data uart1_plat = {
--
1.7.2.dirty
--
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