linux-kernel - [PATCH v5 10/10] Platform: OLPC: Add restart support to XO-1.75 EC driver

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Message-Id: <20190110175845.1203986-11-lkundrak@v3.sk>
Date:   Thu, 10 Jan 2019 18:58:45 +0100
From:   Lubomir Rintel <lkundrak@...sk>
To:     Andy Shevchenko <andy@...radead.org>,
        Darren Hart <dvhart@...radead.org>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Mark Rutland <mark.rutland@....com>,
        platform-driver-x86@...r.kernel.org, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Lubomir Rintel <lkundrak@...sk>
Subject: [PATCH v5 10/10] Platform: OLPC: Add restart support to XO-1.75 EC driver

This hooks to arm_pm_restart instead od utilizing a restart handler
notifier, because the reboot dance on XO 1.75 needs to sleep (it pokes a
GPIO and waits for the EC to initiate the command transaction) and the
restart handler is called in atomic context. Sad.

Signed-off-by: Lubomir Rintel <lkundrak@...sk>

---
Changes since v4:
- Split off from the driver.

 drivers/platform/olpc/Kconfig         |  2 +-
 drivers/platform/olpc/olpc-xo175-ec.c | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/olpc/Kconfig b/drivers/platform/olpc/Kconfig
index 858ac1d2290a..02b232c34444 100644
--- a/drivers/platform/olpc/Kconfig
+++ b/drivers/platform/olpc/Kconfig
@@ -4,7 +4,7 @@ config OLPC_EC
 
 config OLPC_XO175_EC
 	tristate "OLPC XO 1.75 Embedded Controller"
-	depends on ARCH_MMP || COMPILE_TEST
+	depends on ARM && (ARCH_MMP || COMPILE_TEST)
 	select SPI_SLAVE
 	select OLPC_EC
 	help
diff --git a/drivers/platform/olpc/olpc-xo175-ec.c b/drivers/platform/olpc/olpc-xo175-ec.c
index c3a176ce474d..74db06bacc44 100644
--- a/drivers/platform/olpc/olpc-xo175-ec.c
+++ b/drivers/platform/olpc/olpc-xo175-ec.c
@@ -23,6 +23,7 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/spi/spi.h>
+#include <asm/system_misc.h>
 
 struct ec_cmd_t {
 	u8 cmd;
@@ -578,6 +579,14 @@ static int olpc_xo175_ec_set_event_mask(unsigned int mask)
 	return olpc_ec_cmd(CMD_WRITE_EXT_SCI_MASK, args, 2, NULL, 0);
 }
 
+static void olpc_xo175_ec_restart(enum reboot_mode mode, const char *cmd)
+{
+	while (1) {
+		olpc_ec_cmd(CMD_POWER_CYCLE, NULL, 0, NULL, 0);
+		mdelay(1000);
+	}
+}
+
 static void olpc_xo175_ec_power_off(void)
 {
 	while (1) {
@@ -649,6 +658,8 @@ static int olpc_xo175_ec_remove(struct spi_device *spi)
 {
 	if (pm_power_off == olpc_xo175_ec_power_off)
 		pm_power_off = NULL;
+	if (arm_pm_restart == olpc_xo175_ec_restart)
+		arm_pm_restart = NULL;
 
 	spi_slave_abort(spi);
 
@@ -716,6 +727,8 @@ static int olpc_xo175_ec_probe(struct spi_device *spi)
 
 	if (pm_power_off == NULL)
 		pm_power_off = olpc_xo175_ec_power_off;
+	if (arm_pm_restart == NULL)
+		arm_pm_restart = olpc_xo175_ec_restart;
 
 	dev_info(&spi->dev, "OLPC XO-1.75 Embedded Controller driver\n");
 
-- 
2.20.1