pinctrl: meson: rework pinmux ops

This change prepare the introduction of new meson SoC. This new SoC will
share the same gpio/pinconf registers but the pinmux part will be
different. While the format of the data associated with each pinmux group
will change, the way to handle pinmuxing will be similar.

To deal with this new situation, the meson_pmx_struture is kept but the
data associated to it is now generic. This allows to reuse the basic
functions which would otherwise be copy/pasted in each pinmux driver
(such as getting the name a count of groups and functions) Only the
functions actually using this specific data is taken out of the common
code and is handling the SoC pinmuxing

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 108 insertions, 0 deletions

diff --git a/drivers/pinctrl/meson/pinctrl-meson8-pmx.c b/drivers/pinctrl/meson/pinctrl-meson8-pmx.c
new file mode 100644
index 000000000000..b93b058c8a07
--- /dev/null
+++ b/drivers/pinctrl/meson/pinctrl-meson8-pmx.c
@@ -0,0 +1,108 @@
+/*
+ * First generation of pinmux driver for Amlogic Meson SoCs
+ *
+ * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
+ * Copyright (C) 2017 Jerome Brunet  <jbrunet@baylibre.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* For this first generation of pinctrl driver every pinmux group can be
+ * enabled by a specific bit in the first register range. When all groups for
+ * a given pin are disabled the pin acts as a GPIO.
+ */
+#include <linux/device.h>
+#include <linux/regmap.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+
+#include "pinctrl-meson.h"
+#include "pinctrl-meson8-pmx.h"
+
+/**
+ * meson8_pmx_disable_other_groups() - disable other groups using a given pin
+ *
+ * @pc:		meson pin controller device
+ * @pin:	number of the pin
+ * @sel_group:	index of the selected group, or -1 if none
+ *
+ * The function disables all pinmux groups using a pin except the
+ * selected one. If @sel_group is -1 all groups are disabled, leaving
+ * the pin in GPIO mode.
+ */
+static void meson8_pmx_disable_other_groups(struct meson_pinctrl *pc,
+					    unsigned int pin, int sel_group)
+{
+	struct meson_pmx_group *group;
+	struct meson8_pmx_data *pmx_data;
+	int i, j;
+
+	for (i = 0; i < pc->data->num_groups; i++) {
+		group = &pc->data->groups[i];
+		pmx_data = (struct meson8_pmx_data *)group->data;
+		if (pmx_data->is_gpio || i == sel_group)
+			continue;
+
+		for (j = 0; j < group->num_pins; j++) {
+			if (group->pins[j] == pin) {
+				/* We have found a group using the pin */
+				regmap_update_bits(pc->reg_mux,
+						   pmx_data->reg * 4,
+						   BIT(pmx_data->bit), 0);
+			}
+		}
+	}
+}
+
+static int meson8_pmx_set_mux(struct pinctrl_dev *pcdev, unsigned func_num,
+			      unsigned group_num)
+{
+	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
+	struct meson_pmx_func *func = &pc->data->funcs[func_num];
+	struct meson_pmx_group *group = &pc->data->groups[group_num];
+	struct meson8_pmx_data *pmx_data =
+		(struct meson8_pmx_data *)group->data;
+	int i, ret = 0;
+
+	dev_dbg(pc->dev, "enable function %s, group %s\n", func->name,
+		group->name);
+
+	/*
+	 * Disable groups using the same pin.
+	 * The selected group is not disabled to avoid glitches.
+	 */
+	for (i = 0; i < group->num_pins; i++)
+		meson8_pmx_disable_other_groups(pc, group->pins[i], group_num);
+
+	/* Function 0 (GPIO) doesn't need any additional setting */
+	if (func_num)
+		ret = regmap_update_bits(pc->reg_mux, pmx_data->reg * 4,
+					 BIT(pmx_data->bit),
+					 BIT(pmx_data->bit));
+
+	return ret;
+}
+
+static int meson8_pmx_request_gpio(struct pinctrl_dev *pcdev,
+				   struct pinctrl_gpio_range *range,
+				   unsigned offset)
+{
+	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
+
+	meson8_pmx_disable_other_groups(pc, offset, -1);
+
+	return 0;
+}
+
+const struct pinmux_ops meson8_pmx_ops = {
+	.set_mux = meson8_pmx_set_mux,
+	.get_functions_count = meson_pmx_get_funcs_count,
+	.get_function_name = meson_pmx_get_func_name,
+	.get_function_groups = meson_pmx_get_groups,
+	.gpio_request_enable = meson8_pmx_request_gpio,
+};