imx: imx_clock: wdog: Add watchdog clock API

This patch adds a set of functions to enable the clock for each of the
watchdog IP blocks.

Unlike the MMC and UART blocks, the watchdog blocks operate off of the one
root clock, only the clock-gates are enable/disabled individually.

As a consequence the function clock_set_wdog_clk_root_bits() is used to set
the root-slice just once for all of the watchdog blocks.

Future implementations may need to change this model but for now on the one
supported processor and similar NXP SoCs this model should work fine.
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

plat/imx/common/imx_clock.c

@@ -98,3 +98,37 @@ void imx_clock_enable_usdhc(unsigned int usdhc_id, uint32_t usdhc_clk_en_bits)
 	/* Enable the clock gate */
 	imx_clock_gate_enable(ccm_ccgr_id, true);
 }
+
+void imx_clock_enable_wdog(unsigned int wdog_id)
+{
+	unsigned int ccm_ccgr_id = CCM_CCGR_ID_WDOG1 + wdog_id;
+
+	/* Check for error */
+	if (wdog_id > MXC_MAX_WDOG_NUM)
+		return;
+
+	/* Enable the clock gate */
+	imx_clock_gate_enable(ccm_ccgr_id, true);
+}
+
+void imx_clock_disable_wdog(unsigned int wdog_id)
+{
+	unsigned int ccm_trgt_id = CCM_TRT_ID_WDOG_CLK_ROOT;
+	unsigned int ccm_ccgr_id = CCM_CCGR_ID_WDOG1 + wdog_id;
+
+	/* Check for error */
+	if (wdog_id > MXC_MAX_WDOG_NUM)
+		return;
+
+	/* Disable the clock gate */
+	imx_clock_gate_enable(ccm_ccgr_id, false);
+
+	/* Clear the target */
+	imx_clock_target_clr(ccm_trgt_id, 0xFFFFFFFF);
+}
+
+void imx_clock_set_wdog_clk_root_bits(uint32_t wdog_clk_root_en_bits)
+{
+	/* Enable the common clock root just once */
+	imx_clock_target_set(CCM_TRT_ID_WDOG_CLK_ROOT, wdog_clk_root_en_bits);
+}

plat/imx/common/include/imx_clock.h

@@ -992,5 +992,8 @@ void imx_clock_init(void);
 void imx_clock_enable_uart(unsigned int uart_id, uint32_t uart_clk_en_bits);
 void imx_clock_disable_uart(unsigned int uart_id);
 void imx_clock_enable_usdhc(unsigned int usdhc_id, uint32_t usdhc_clk_en_bits);
+void imx_clock_set_wdog_clk_root_bits(uint32_t wdog_clk_root_en_bits);
+void imx_clock_enable_wdog(unsigned int wdog_id);
+void imx_clock_disable_wdog(unsigned int wdog_id);
 
 #endif /* __IMX_CLOCK_H__ */