linux-kernel - [PATCH V2] gpio: mxc: add clock operation

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Date:   Tue, 22 May 2018 09:15:17 +0800
From:   Anson Huang <Anson.Huang@....com>
To:     linus.walleij@...aro.org
Cc:     Linux-imx@....com, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH V2] gpio: mxc: add clock operation

Some i.MX SoCs have GPIO clock gates in CCM CCGR, such as
i.MX6SLL, need to enable clocks before accessing GPIO
registers, add optional clock operation for GPIO driver.

Signed-off-by: Anson Huang <Anson.Huang@....com>
---
changes since V1:
	add missing clk header;
	remove FSF addresses in copyright to avoid check patch ERROR.
 drivers/gpio/gpio-mxc.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
index 11ec722..2026f94 100644
--- a/drivers/gpio/gpio-mxc.c
+++ b/drivers/gpio/gpio-mxc.c
@@ -14,12 +14,9 @@
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
+#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
@@ -60,6 +57,7 @@ struct mxc_gpio_hwdata {
 struct mxc_gpio_port {
 	struct list_head node;
 	void __iomem *base;
+	struct clk *clk;
 	int irq;
 	int irq_high;
 	struct irq_domain *domain;
@@ -434,6 +432,17 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 	if (port->irq < 0)
 		return port->irq;
 
+	/* the controller clock is optional */
+	port->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(port->clk))
+		port->clk = NULL;
+
+	err = clk_prepare_enable(port->clk);
+	if (err) {
+		dev_err(&pdev->dev, "Unable to enable clock.\n");
+		return err;
+	}
+
 	/* disable the interrupt and clear the status */
 	writel(0, port->base + GPIO_IMR);
 	writel(~0, port->base + GPIO_ISR);
@@ -502,6 +511,7 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 out_irqdomain_remove:
 	irq_domain_remove(port->domain);
 out_bgio:
+	clk_disable_unprepare(port->clk);
 	dev_info(&pdev->dev, "%s failed with errno %d\n", __func__, err);
 	return err;
 }
-- 
2.7.4