[v3,4/5] clk: twl: add clock driver for TWL6032

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index c30099866174d..3944f081ebade 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -277,6 +277,15 @@  config COMMON_CLK_S2MPS11
 	  clock. These multi-function devices have two (S2MPS14) or three
 	  (S2MPS11, S5M8767) fixed-rate oscillators, clocked at 32KHz each.
 
+config CLK_TWL
+	tristate "Clock driver for the TWL PMIC family"
+	depends on TWL4030_CORE
+	help
+	  Enable support for controlling the clock resources on TWL family
+	  PMICs. These devices have some 32K clock outputs which can be
+	  controlled by software. For now, only the TWL6032 clocks are
+	  supported.
+
 config CLK_TWL6040
 	tristate "External McPDM functional clock from twl6040"
 	depends on TWL6040_CORE
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 18969cbd4bb1e..86e46adcb619c 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -72,6 +72,7 @@  obj-$(CONFIG_COMMON_CLK_STM32H7)	+= clk-stm32h7.o
 obj-$(CONFIG_COMMON_CLK_STM32MP157)	+= clk-stm32mp1.o
 obj-$(CONFIG_COMMON_CLK_TPS68470)      += clk-tps68470.o
 obj-$(CONFIG_CLK_TWL6040)		+= clk-twl6040.o
+obj-$(CONFIG_CLK_TWL)			+= clk-twl.o
 obj-$(CONFIG_ARCH_VT8500)		+= clk-vt8500.o
 obj-$(CONFIG_COMMON_CLK_RS9_PCIE)	+= clk-renesas-pcie.o
 obj-$(CONFIG_COMMON_CLK_SI521XX)	+= clk-si521xx.o
diff --git a/drivers/clk/clk-twl.c b/drivers/clk/clk-twl.c
new file mode 100644
index 0000000000000..09006e53a32ec
--- /dev/null
+++ b/drivers/clk/clk-twl.c
@@ -0,0 +1,197 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Clock driver for twl device.
+ *
+ * inspired by the driver for the Palmas device
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/mfd/twl.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define VREG_STATE              2
+#define TWL6030_CFG_STATE_OFF   0x00
+#define TWL6030_CFG_STATE_ON    0x01
+#define TWL6030_CFG_STATE_MASK  0x03
+
+struct twl_clock_info {
+	struct device *dev;
+	u8 base;
+	struct clk_hw hw;
+};
+
+static inline int
+twlclk_read(struct twl_clock_info *info, unsigned int slave_subgp,
+	    unsigned int offset)
+{
+	u8 value;
+	int status;
+
+	status = twl_i2c_read_u8(slave_subgp, &value,
+				 info->base + offset);
+	return (status < 0) ? status : value;
+}
+
+static inline int
+twlclk_write(struct twl_clock_info *info, unsigned int slave_subgp,
+	     unsigned int offset, u8 value)
+{
+	return twl_i2c_write_u8(slave_subgp, value,
+				info->base + offset);
+}
+
+static inline struct twl_clock_info *to_twl_clks_info(struct clk_hw *hw)
+{
+	return container_of(hw, struct twl_clock_info, hw);
+}
+
+static unsigned long twl_clks_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	return 32768;
+}
+
+static int twl6032_clks_prepare(struct clk_hw *hw)
+{
+	struct twl_clock_info *cinfo = to_twl_clks_info(hw);
+	int ret;
+
+	ret = twlclk_write(cinfo, TWL_MODULE_PM_RECEIVER, VREG_STATE,
+			   TWL6030_CFG_STATE_ON);
+	if (ret < 0)
+		dev_err(cinfo->dev, "clk prepare failed\n");
+
+	return ret;
+}
+
+static void twl6032_clks_unprepare(struct clk_hw *hw)
+{
+	struct twl_clock_info *cinfo = to_twl_clks_info(hw);
+	int ret;
+
+	ret = twlclk_write(cinfo, TWL_MODULE_PM_RECEIVER, VREG_STATE,
+			   TWL6030_CFG_STATE_OFF);
+	if (ret < 0)
+		dev_err(cinfo->dev, "clk unprepare failed\n");
+}
+
+static int twl6032_clks_is_prepared(struct clk_hw *hw)
+{
+	struct twl_clock_info *cinfo = to_twl_clks_info(hw);
+	int val;
+
+	val = twlclk_read(cinfo, TWL_MODULE_PM_RECEIVER, VREG_STATE);
+	if (val < 0) {
+		dev_err(cinfo->dev, "clk read failed\n");
+		return val;
+	}
+
+	val &= TWL6030_CFG_STATE_MASK;
+
+	return val == TWL6030_CFG_STATE_ON;
+}
+
+static const struct clk_ops twl6032_clks_ops = {
+	.prepare	= twl6032_clks_prepare,
+	.unprepare	= twl6032_clks_unprepare,
+	.is_prepared	= twl6032_clks_is_prepared,
+	.recalc_rate	= twl_clks_recalc_rate,
+};
+
+struct twl_clks_data {
+	struct clk_init_data init;
+	u8 base;
+};
+
+static const struct twl_clks_data twl6032_clks[] = {
+	{
+		.init = {
+			.name = "clk32kg",
+			.ops = &twl6032_clks_ops,
+			.flags = CLK_IGNORE_UNUSED,
+		},
+		.base = 0x8C,
+	},
+	{
+		.init = {
+			.name = "clk32kaudio",
+			.ops = &twl6032_clks_ops,
+			.flags = CLK_IGNORE_UNUSED,
+		},
+		.base = 0x8F,
+	},
+	{
+		/* sentinel */
+	}
+};
+
+static int twl_clks_probe(struct platform_device *pdev)
+{
+	struct clk_hw_onecell_data *clk_data;
+	const struct twl_clks_data *hw_data;
+
+	struct twl_clock_info *cinfo;
+	int ret;
+	int i;
+	int count;
+
+	hw_data = twl6032_clks;
+	for (count = 0; hw_data[count].init.name; count++)
+		;
+
+	clk_data = devm_kzalloc(&pdev->dev,
+				struct_size(clk_data, hws, count),
+				GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	clk_data->num = count;
+	cinfo = devm_kcalloc(&pdev->dev, count, sizeof(*cinfo), GFP_KERNEL);
+	if (!cinfo)
+		return -ENOMEM;
+
+	for (i = 0; i < count; i++) {
+		cinfo[i].base = hw_data[i].base;
+		cinfo[i].dev = &pdev->dev;
+		cinfo[i].hw.init = &hw_data[i].init;
+		ret = devm_clk_hw_register(&pdev->dev, &cinfo[i].hw);
+		if (ret) {
+			dev_err(&pdev->dev, "Fail to register clock %s, %d\n",
+				hw_data[i].init.name, ret);
+			return ret;
+		}
+		clk_data->hws[i] = &cinfo[i].hw;
+	}
+
+	ret = devm_of_clk_add_hw_provider(&pdev->dev,
+					  of_clk_hw_onecell_get, clk_data);
+	if (ret < 0)
+		dev_err(&pdev->dev, "Fail to add clock driver, %d\n", ret);
+
+	return ret;
+}
+
+static const struct platform_device_id twl_clks_id[] = {
+	{
+		.name = "twl6032-clk",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(platform, twl_clks_id);
+
+static struct platform_driver twl_clks_driver = {
+	.driver = {
+		.name = "twl-clk",
+	},
+	.probe = twl_clks_probe,
+	.id_table = twl_clks_id,
+};
+
+module_platform_driver(twl_clks_driver);
+
+MODULE_DESCRIPTION("Clock driver for TWL Series Devices");
+MODULE_LICENSE("GPL");